Encoder, decoder, and corresponding method and apparatus

Abstract

This provides a method for decoding a coded video bitstream. [Solution] The method includes the steps of: obtaining a reference layer syntax element by parsing a coded video bitstream; determining whether a layer having index j is a reference layer of a layer having index i based on the value of the reference layer syntax element; and, if the condition is met, predicting the picture of the layer having index i based on the layer having index j. The value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, and the condition is that the layer having index j is a reference layer of the layer having index i.

Description

[Technical Field]

[0001] [Cross-references to related applications] This application claims priority to International Application PCT / CN2019 / 130804, filed on 31 December 2019, and International Application PCT / CN2020 / 070153, filed on 2 January 2020, and incorporates the entire contents of those applications by reference.

[0002] [Technical field] The embodiments of this application (disclosure) generally relate to the field of picture processing, and more particularly to encoders, decoders, and corresponding methods and apparatus. [Background technology]

[0003] Video coding (video encoding and / or decoding) is used in a wide range of digital video applications, such as broadcast digital television (TV), video transmission over the Internet and mobile networks, real-time conversation applications like video chat, video conferencing, digital video discs (DVDs) and Blu-ray discs, video content acquisition and editing systems, and camcorders in security applications.

[0004] Even relatively short videos can require a considerable amount of video data to depict, which can cause difficulties when data is streamed or transmitted across communication networks with limited bandwidth. Therefore, video data is generally compressed before being transmitted across modern telecommunications networks. Video size can also be a concern when video is stored on storage devices, as memory resources can be limited. Video compression devices often use software and / or hardware at the source to encode video data before transmission or storage, thereby reducing the amount of data required to represent the digital video image. The compressed data is then received at the destination by a video decompression device that decodes the video data. Due to limited network resources and the ever-increasing demand for higher video quality, improved compression and decompression techniques that improve the compression ratio with little to no sacrifice of picture quality are desirable. [Overview of the project]

[0005] Embodiments of this application provide apparatus and methods for encoding and decoding according to independent claims.

[0006] The above and other objectives are achieved by the subject matter of the independent claim. Further forms of implementation are evident from the dependent claims, detailed description and drawings.

[0007] Specific embodiments are outlined in the attached independent claims, and other embodiments are outlined in the dependent claims.

[0008] According to a first aspect, the present invention relates to a method for decoding a coded video bitstream, the method being performed by an apparatus for decoding a coded video bitstream. The steps include: obtaining a reference layer syntax element by parsing a coded video bitstream, wherein the value of the reference layer syntax element specifies whether the layer having index k is a direct reference layer of the layer having index i, and both i and k are integers and greater than or equal to 0; The steps include determining whether a layer having index j is a reference layer of a layer having index i, based on the value of the reference layer syntax element, wherein the layer having index j is a reference layer of a layer having index k, and j is an integer and greater than or equal to 0, and Steps include predicting the picture of the layer having index i based on the layer having index j, provided that the conditions are met, wherein the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, and the condition is that the layer having index j is a reference layer of the layer having index i. Includes.

[0009] In a possible implementation of the method according to the first embodiment, if the value of the reference layer syntax element specifies that the layer having index k is a direct reference layer of the layer having index i, then the layer having index j is a reference layer of the layer having index i.

[0010] According to a second aspect, the present invention relates to a method for decoding a coded video bitstream, the method being performed by an apparatus for decoding a coded video bitstream. The steps include: obtaining a reference layer syntax element by parsing a coded video bitstream, wherein the value of the reference layer syntax element specifies whether the layer having index j is a direct reference layer of the layer having index i, and both i and j are integers and greater than or equal to 0; Steps include predicting the picture of the layer having index i based on the layer having index j, provided that the conditions are met, wherein the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, and the condition is that the value of the reference layer syntax element specifies that the layer having index j is a direct reference layer of the layer having index i. Includes.

[0011] In any of the preceding implementations of the first embodiment, or in possible implementations of the methods according to the first embodiment or the second embodiment itself, the reference layer syntax element is a video parameter set (VPS) level syntax element, where the VPS applies to the layer having index j and the layer having index i.

[0012] In any of the preceding implementations of the first embodiment, or in possible implementations of the methods according to the first embodiment or the second embodiment itself, the chroma format-related syntax elements are sequence parameter set (SPS) level syntax elements, where the SPS is applied to a layer having index j or a layer having index i.

[0013] In any of the preceding implementation methods of the first embodiment, or any preceding implementation method of the first embodiment or the second embodiment itself, The step of obtaining a chroma format-related syntax element applied to a layer having index i and a chroma format-related syntax element applied to a layer having index j by parsing a coded video bitstream, further comprising the condition that the value of the chroma format-related syntax element applied to the layer having index i is the same as the value of the chroma format-related syntax element applied to the layer having index j.

[0014] In any of the preceding implementation methods of the first embodiment or in any possible implementation of the method according to the first embodiment itself, The process further includes the step of stopping decoding the coded video bitstream if the layer having index j is a reference layer of the layer having index i, and the value of the chroma format-related syntax element applied to the layer having index i is not the same as the value of the chroma format-related syntax element applied to the layer having index j.

[0015] In any of the preceding implementation methods of the first embodiment or in any possible implementation of the method according to the first embodiment itself, If the layer having index j is not a reference layer of the layer having index i, the process further includes the step of predicting the picture of the layer having index i without using the layer having index j.

[0016] In any of the preceding implementation methods of the first embodiment, or any preceding implementation method of the first embodiment or the second embodiment itself, If the conditions are met, the method further includes determining that the value of the chroma format-related syntax element applied to the layer having index i is the value of the chroma format-related syntax element applied to the layer having index j, without obtaining the chroma format-related syntax element applied to the layer having index i by parsing the coded video bitstream.

[0017] According to a third aspect, the present invention relates to a method for decoding a coded video bitstream, the method being performed by an apparatus for decoding a coded video bitstream. The steps include: obtaining a reference layer syntax element by parsing a coded video bitstream, wherein the value of the reference layer syntax element specifies whether the layer having index k is a direct reference layer of the layer having index i, and both i and k are integers and greater than or equal to 0; The steps include determining whether a layer having index j is a reference layer of a layer having index i, based on the value of the reference layer syntax element, wherein the layer having index j is a reference layer of a layer having index k, and j is an integer and greater than or equal to 0, and Steps include predicting the picture of the layer having index i based on the layer having index j, provided that the conditions are met, wherein the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j, and the condition is that the layer having index j is the reference layer of the layer having index i. Includes.

[0018] In a possible implementation of the method according to the third aspect itself, when the value of the reference layer syntax element specifies that the layer with index k is the direct reference layer of the layer with index i, the layer with index j is the reference layer of the layer with index i.

[0019] According to a fourth aspect, the present invention relates to a method for decoding a coded video bitstream, the method being performed by an apparatus for decoding a coded video bitstream. The method comprises obtaining a reference layer syntax element by parsing the coded video bitstream, the value of the reference layer syntax element specifying whether the layer with index j is the direct reference layer of the layer with index i, both i and j being integers and being greater than or equal to 0; predicting a picture of the layer with index i based on the layer with index j when a condition is satisfied, the value of the syntax element related to the bit depth applied to the layer with index i being the same as the value of the syntax element related to the bit depth applied to the layer with index j, the condition including that the value of the reference layer syntax element specifies that the layer with index j is the direct reference layer of the layer with index i; and

[0020] In any of the previous implementations of the third aspect or in a possible implementation of the method according to the first aspect or the fourth aspect itself, the reference layer syntax element is a syntax element at the video parameter set (VPS) level, and the VPS is applied to the layer with index j and the layer with index i.

[0021] In any of the preceding implementations of the third embodiment or of the methods according to the first embodiment or the fourth embodiment itself, the bit depth-related syntax elements are sequence parameter set (SPS) level syntax elements, where the SPS is applied to a layer having index j or a layer having index i.

[0022] In any of the preceding implementation methods of the third aspect, or any preceding implementation method of the third or fourth aspect, or the fourth aspect itself, The step of obtaining bit depth-related syntax elements applied to a layer having index i and bit depth-related syntax elements applied to a layer having index j by parsing a coded video bitstream, further comprising the condition that the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j.

[0023] In any of the preceding implementation methods of the third embodiment or the method of the third embodiment itself, The process further includes the step of stopping decoding the coded video bitstream if the layer having index j is a reference layer of the layer having index i, and the value of the bit depth-related syntax element applied to the layer having index i is not the same as the value of the bit depth-related syntax element applied to the layer having index j.

[0024] In any of the preceding implementation methods of the third embodiment or the method of the third embodiment itself, If the layer having index j is not a reference layer of the layer having index i, the process further includes the step of predicting the picture of the layer having index i without using the layer having index j.

[0025] In any of the preceding implementation methods of the third aspect, or any preceding implementation method of the third or fourth aspect, or the fourth aspect itself, If the conditions are met, the method further includes determining that the value of the bit depth-related syntax element applied to the layer having index i is the value of the bit depth-related syntax element applied to the layer having index j, without obtaining the bit depth-related syntax element applied to the layer having index i by parsing the coded video bitstream.

[0026] In any of the preceding implementations of the third embodiment, or any of the preceding implementations of the third or fourth embodiment, or in any possible implementation of the method according to the fourth embodiment itself, the bit depth-related syntax element specifies the bit depth of the luma and chroma samples of the picture in the layer to which the bit depth-related syntax element applies.

[0027] According to a fifth aspect, the present invention relates to a method for encoding video. The method is performed by an apparatus for encoding video. The step of determining whether a layer having index j is a direct reference layer of a layer having index i, where both i and j are integers and greater than or equal to 0, and The steps include: encoding a reference layer syntax element into a video bitstream that has a value indicating that the layer having index j is a direct reference layer of the layer having index i, and encoding a chroma format-related syntax element applied to the layer having index i and a chroma format-related syntax element applied to the layer having index j into a video bitstream, wherein the value of the chroma format-related syntax element applied to the layer having index i is the same as the value of the chroma format-related syntax element applied to the layer having index j; and Includes.

[0028] In possible implementations of the method by the fifth aspect itself, If the layer having index j is a direct reference layer of the layer having index i, the process further includes the step of predicting the picture of the layer having index i based on the layer having index j.

[0029] In possible implementations of the method by the fifth aspect itself, If the layer having index j is not a reference layer of the layer having index i, the process further includes the step of predicting the picture of the layer having index i without using the layer having index j.

[0030] According to a sixth aspect, the present invention relates to a method for encoding video. The method is performed by an apparatus for encoding video. The step of determining whether a layer having index j is a direct reference layer of a layer having index i, where both i and j are integers and greater than or equal to 0, and The steps include: encoding a reference layer syntax element into a video bitstream that has a value indicating that the layer having index j is a direct reference layer of the layer having index i, and encoding a bit depth-related syntax element applied to the layer having index i and a bit depth-related syntax element applied to the layer having index j into a video bitstream, wherein the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j; and Includes.

[0031] In possible implementations of the method by the sixth aspect itself, If the layer having index j is a direct reference layer of the layer having index i, the process further includes the step of predicting the picture of the layer having index i based on the layer having index j.

[0032] In possible implementations of the method by the sixth aspect itself, If the layer having index j is not a reference layer of the layer having index i, the process further includes the step of predicting the picture of the layer having index i without using the layer having index j.

[0033] In any of the preceding implementations of the sixth aspect or in possible implementations of the method according to the sixth aspect itself, the bit depth-related syntax element specifies the bit depth of the luma and chroma samples of the picture in the layer to which the bit depth-related syntax element applies.

[0034] According to a seventh aspect, the present invention relates to an apparatus for decoding a coded video bitstream. The apparatus is An acquisition unit configured to obtain a reference layer syntax element by parsing a coded video bitstream, wherein the value of the reference layer syntax element specifies whether the layer having index k is a direct reference layer of the layer having index i, and both i and k are integers and greater than or equal to 0. A decision unit configured to determine whether a layer having index j is a reference layer of a layer having index i, based on the value of the reference layer syntax element, wherein the layer having index j is a reference layer of the layer having index k, and j is an integer and greater than or equal to 0. A prediction unit configured to predict the picture of a layer having index i based on a layer having index j, provided the conditions are met, wherein the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, and the conditions include the layer having index j being a reference layer of the layer having index i. Includes.

[0035] In a possible implementation of the seventh aspect of the method, if the value of the reference layer syntax element specifies that the layer having index k is a direct reference layer of the layer having index i, then the layer having index j is a reference layer of the layer having index i.

[0036] According to the eighth aspect, the present invention relates to an apparatus for decoding a coded video bitstream. The apparatus is An acquisition unit configured to obtain a reference layer syntax element by parsing a coded video bitstream, wherein the value of the reference layer syntax element specifies whether the layer having index j is a direct reference layer of the layer having index i, and both i and j are integers and greater than or equal to 0. A prediction unit configured to predict the picture of a layer having index i based on a layer having index j, provided that the conditions are met, wherein the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, and the conditions include the value of the reference layer syntax element specifying that the layer having index j is a direct reference layer of the layer having index i. Includes.

[0037] In any of the preceding implementations of the seventh aspect, or in possible implementations of the method according to the seventh aspect or the eighth aspect itself, the reference layer syntax element is a video parameter set (VPS) level syntax element, where the VPS applies to the layer having index j and the layer having index i.

[0038] In any of the preceding implementations of the seventh aspect, or in possible implementations of the method according to the seventh aspect or the eighth aspect itself, the chroma format-related syntax elements are sequence parameter set (SPS) level syntax elements, where the SPS is applied to a layer having index j or a layer having index i.

[0039] In any of the preceding implementation methods of the seventh aspect, or any preceding implementation method of the seventh aspect or the eighth aspect, or in any of the eighth aspects itself, The acquisition unit is further configured to acquire a chroma format-related syntax element applied to the layer having index i and a chroma format-related syntax element applied to the layer having index j by parsing a coded video bitstream, the condition further including that the value of the chroma format-related syntax element applied to the layer having index i is the same as the value of the chroma format-related syntax element applied to the layer having index j.

[0040] Possible implementations of any of the preceding implementations of the seventh embodiment or the method of the seventh embodiment itself further include a stop unit, The stop unit is configured to stop decoding the coded video bitstream if the layer having index j is a reference layer of the layer having index i, and the value of the chroma format-related syntax element applied to the layer having index i is not the same as the value of the chroma format-related syntax element applied to the layer having index j.

[0041] In any of the preceding implementation methods of the seventh aspect, or in any possible implementation of the method according to the seventh aspect itself, The acquisition unit is further configured to predict the picture of the layer with index i without using the layer with index j if the layer with index j is not the reference layer of the layer with index i.

[0042] In any of the preceding implementation methods of the seventh aspect, or any preceding implementation method of the seventh aspect or the eighth aspect, or in any of the eighth aspects itself, The decision unit is further configured to determine, if the conditions are met, that the value of the chroma format-related syntax element applied to the layer having index i is the value of the chroma format-related syntax element applied to the layer having index j, without obtaining the chroma format-related syntax element applied to the layer having index i by parsing the coded video bitstream.

[0043] According to a ninth aspect, the present invention relates to an apparatus for decoding a coded video bitstream. The apparatus is An acquisition unit configured to obtain a reference layer syntax element by parsing a coded video bitstream, wherein the value of the reference layer syntax element specifies whether the layer having index k is a direct reference layer of the layer having index i, and both i and k are integers and greater than or equal to 0. A decision unit configured to determine whether a layer having index j is a reference layer of a layer having index i, based on the value of the reference layer syntax element, wherein the layer having index j is a reference layer of the layer having index k, and j is an integer and greater than or equal to 0. A prediction unit configured to predict the picture of a layer having index i based on a layer having index j, provided that the conditions are met, wherein the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j, and the conditions include that the layer having index j is a reference layer of the layer having index i. Includes.

[0044] In a possible implementation of the method according to the ninth aspect itself, if the value of the reference layer syntax element specifies that the layer having index k is a direct reference layer of the layer having index i, then the layer having index j is a reference layer of the layer having index i.

[0045] According to a tenth aspect, the present invention relates to an apparatus for decoding a coded video bitstream. The apparatus is An acquisition unit configured to obtain a reference layer syntax element by parsing a coded video bitstream, wherein the value of the reference layer syntax element specifies whether the layer having index j is a direct reference layer of the layer having index i, and both i and j are integers and greater than or equal to 0. A prediction unit configured to predict the picture of a layer having index i based on a layer having index j, provided that the conditions are met, wherein the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j, and the conditions include the value of the reference layer syntax element specifying that the layer having index j is a direct reference layer of the layer having index i. Includes.

[0046] In any of the preceding implementations of the ninth aspect, or in possible implementations of the method according to the ninth aspect or the tenth aspect itself, the reference layer syntax element is a video parameter set (VPS) level syntax element, where the VPS applies to the layer having index j and the layer having index i.

[0047] In any of the preceding implementations of the ninth aspect, or in possible implementations of the method according to the ninth aspect or the tenth aspect itself, bit depth-related syntax elements are sequence parameter set (SPS) level syntax elements, where the SPS is applied to a layer having index j or a layer having index i.

[0048] In any of the preceding implementation methods of the 9th aspect, or any preceding implementation method of the 9th aspect or the 10th aspect, or in any possible implementation of the 10th aspect itself, The acquisition unit is further configured to acquire bit depth-related syntax elements applied to the layer having index i and bit depth-related syntax elements applied to the layer having index j by parsing a coded video bitstream, the condition further including that the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j.

[0049] Possible implementations of any of the preceding implementations of the ninth aspect or the method of the ninth aspect itself further include a stop unit, The stop unit is configured to stop decoding the coded video bitstream if the layer having index j is a reference layer to the layer having index i, and the value of the bit depth-related syntax element applied to the layer having index i is not the same as the value of the bit depth-related syntax element applied to the layer having index j.

[0050] In any of the preceding implementation methods of the ninth aspect, or in any possible implementation of the method according to the ninth aspect itself, The prediction unit is further configured to predict the picture of the layer with index i without using the layer with index j if the layer with index j is not the reference layer of the layer with index i.

[0051] In any of the preceding implementation methods of the 9th aspect, or any preceding implementation method of the 9th aspect or the 10th aspect, or in any possible implementation of the 10th aspect itself, The decision unit is further configured to determine that the value of the bit depth-related syntax element applied to the layer having index i is the value of the bit depth-related syntax element applied to the layer having index j, without obtaining the bit depth-related syntax element applied to the layer having index i by parsing the coded video bitstream.

[0052] In any of the preceding implementations of the ninth aspect, or any of the preceding implementations of the ninth or tenth aspect, or in any possible implementation of the method according to the tenth aspect itself, the bit depth-related syntax element specifies the bit depth of the luma and chroma samples of the picture in the layer to which the bit depth-related syntax element applies.

[0053] According to an eleventh aspect, the present invention relates to an apparatus for encoding video. The apparatus is A decision unit configured to determine whether a layer having index j is a direct reference layer of a layer having index i, wherein both i and j are integers and greater than or equal to 0, An encoding unit configured to encode a reference layer syntax element into a video bitstream that has a value specifying that the layer having index j is a direct reference layer of the layer having index i, and to encode a chroma format related syntax element applied to the layer having index i and a chroma format related syntax element applied to the layer having index j into a video bitstream, wherein the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, and Includes.

[0054] A possible implementation of the method according to the eleventh aspect further includes a first prediction unit, The first prediction unit is configured to predict the picture of the layer having index i based on the layer having index j, if the layer having index j is a direct reference layer of the layer having index i.

[0055] A possible implementation of the method according to the eleventh aspect further includes a second prediction unit, The first prediction unit is configured to predict the picture of the layer having index i without using the layer having index j if the layer having index j is not the reference layer of the layer having index i.

[0056] According to a twelfth aspect, the present invention relates to an apparatus for encoding video. The apparatus is A decision unit configured to determine whether a layer having index j is a direct reference layer of a layer having index i, wherein both i and j are integers and greater than or equal to 0, An encoding unit configured to encode a reference layer syntax element into a video bitstream that has a value specifying that the layer having index j is a direct reference layer of the layer having index i, and to encode a bit depth-related syntax element applied to the layer having index i and a bit depth-related syntax element applied to the layer having index j into a video bitstream, wherein the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j, and Includes.

[0057] A possible implementation of the method according to the twelfth aspect further includes a first prediction unit, The first prediction unit is configured to predict the picture of the layer having index i based on the layer having index j, if the layer having index j is a direct reference layer of the layer having index i.

[0058] A possible implementation of the method according to the twelfth aspect further includes a second prediction unit, The second prediction unit is configured to predict the picture of the layer with index i without using the layer with index j if the layer with index j is not the reference layer of the layer with index i.

[0059] In any of the preceding implementations of the 12th embodiment or in any possible implementation of the method according to the 12th embodiment itself, the bit depth-related syntax element specifies the bit depth of the luma and chroma samples of the picture in the layer to which the bit depth-related syntax element is applied.

[0060] According to the 13th aspect, the present application relates to an encoder including a processing circuit for performing the method according to the 5th or 6th aspect.

[0061] According to the fourteenth aspect, the present application relates to a decoder including a processing circuit for carrying out the method according to the first, second, third, or fourth aspect.

[0062] According to the fourteenth aspect, the present application relates to a computer program product which includes program code for performing a method according to any one of the first to sixth aspects when executed on a computer or processor.

[0063] According to the 15th aspect, the present application relates to a decoder comprising one or more processors and a non-temporary computer-readable storage medium coupled to the one or more processors and storing a program for execution by the processors, wherein the decoder is configured to perform a method according to the first, second, third, or fourth aspect when executed by the processors.

[0064] According to the sixteenth aspect, the present application relates to an encoder comprising one or more processors and a non-temporary computer-readable storage medium coupled to the processors and storing a program for execution by the processors, wherein the program, when executed by the processor, configures the encoder to perform the method according to the fifth or sixth aspect.

[0065] According to the 17th aspect, the present application relates to a non-temporary computer-readable medium for carrying program code that, when executed by a computer device, causes the computer device to execute one of the methods of the first to sixth aspects.

[0066] According to the 18th aspect, the present application relates to a non-temporary storage medium including an encoded bitstream decoded by an image decoding device, wherein the bitstream includes encoded data of at least one layer, and further includes a chroma format-related syntax element of a layer having index i and a chroma format-related syntax element of a layer having index j, where the layer having index j is a reference layer of the layer having index i, the value of the chroma format-related syntax element of the layer having index i is the same as the value of the chroma format-related syntax element of the layer having index j, and both i and j are integers and greater than or equal to 0.

[0067] According to the 19th aspect, the present application relates to a non-temporary storage medium including an encoded bitstream decoded by an image decoding device, wherein the bitstream includes encoded data of at least one layer, and further includes a bit depth-related syntax element of a layer having index i and a bit depth-related syntax element of a layer having index j, where the layer having index j is a reference layer of the layer having index i, the value of the bit depth-related syntax element of the layer having index i is the same as the value of the bit depth-related syntax element of the layer having index j, and both i and j are integers and greater than or equal to 0.

[0068] In a possible implementation of the method according to the 19th aspect itself, the bit depth-related syntax element specifies the bit depth of the luma and chroma samples of the picture in the layer to which the bit depth-related syntax element is applied.

[0069] In a possible implementation of the preceding implementation of either the 18th or 19th aspect, or of the method according to the 19th aspect itself, the bitstream further includes a reference layer syntax element, the value of which specifies that the layer having index j is a reference layer of the layer having index i, or that the layer having index j is a direct reference layer of the layer having index i.

[0070] According to a 20th aspect, the present invention relates to a method for decoding a coded video bitstream, the method being performed by an apparatus for decoding a coded video bitstream, the method comprising the steps of parsing a first syntax element used to derive a maximum allowable number of layers, and predicting the picture of the current layer, provided that a first condition is met and the value of a second syntax element specifying a third syntax element is not present in the coded video bitstream, the first condition being that the value of the first syntax element specifies that the maximum allowable number of layers is 1.

[0071] In a possible implementation of the method according to the 20th aspect, the first syntax element is contained in the VPS of the coded video bitstream and is used to derive the maximum number of allowed layers in each CVS that references the VPS.

[0072] In any possible implementation of a preceding implementation of the 20th embodiment or of the method according to the 20th embodiment itself, predicting a picture of the current layer having an index on the condition that the value of the second syntax element specifying the third syntax element does not exist in the coded video bitstream includes predicting a picture of the current layer having an index on the condition that the value of the second syntax element specifying the third syntax element does not exist in the PH that references the SPS of the coded video bitstream, wherein the second syntax element is included in the SPS.

[0073] In any possible implementation of the preceding implementation of the 20th aspect or of the method according to the 20th aspect itself, the method further includes the step of determining that, when the first condition is met, the value of the second syntax element specifying the third syntax element does not exist in the coded video bitstream.

[0074] In any of the preceding implementations of the 20th embodiment or in any possible implementation of the method according to the 20th embodiment itself, the third syntax element specifies whether the syntax element for the POC MSB value of the current picture is present in PH, and the third syntax element is included in PH.

[0075] According to a 21st aspect, the present invention relates to a method for decoding a coded video bitstream, the method being performed by an apparatus for decoding a coded video bitstream, the method comprising: parsing a first syntax element that specifies whether a layer having index i uses inter-layer prediction, i being an integer and greater than 0; and predicting a picture of a layer having index i, provided that a first condition is met, including the value of the first syntax element specifying that the layer having index j is a direct reference layer of the layer having index i, the value of the chroma format-related syntax element of the layer having index i being the same as the value of the chroma format-related syntax element of the layer having index j, where j is an integer and greater than 0.

[0076] In a possible implementation of the method according to the 21st aspect itself, the method further includes the step of determining that, when the first condition including is met, the value of the chroma format-related syntax element of the layer having index i is the same as the value of the chroma format-related syntax element of the layer having index j.

[0077] In any of the preceding implementations of the 21st embodiment or possible implementations of the method according to the 21st embodiment itself, the chroma format-related syntax elements include chroma_format_idc or separate_colour_plane_flag.

[0078] According to a 22nd aspect, the present invention relates to a method for decoding a coded video bitstream, the method being performed by an apparatus for decoding a coded video bitstream, the method comprising: parsing a first syntax element that specifies whether a layer having index i uses inter-layer prediction, i being an integer and greater than 0; and predicting a picture of a layer having index i, provided that a first condition is met, including the value of the first syntax element specifying that the layer having index j is a direct reference layer of the layer having index i, the value of the bit-depth related syntax element of the layer having index i being the same as the value of the bit-depth related syntax element of the layer having index j, where j is an integer and greater than 0.

[0079] In a possible implementation of the method according to the 22nd aspect itself, the method further includes the step of determining that, when the first condition including is met, the value of the bit depth-related syntax element of the layer having index i is the same as the value of the bit depth-related syntax element of the layer having index j.

[0080] In any of the preceding implementations of the 22nd embodiment or possible implementations of the method according to the 22nd embodiment itself, the bit depth-related syntax element includes bit_depth_minus8.

[0081] According to a 23rd aspect, the present invention relates to a method for decoding a coded video bitstream, the method being performed by an apparatus for decoding a coded video bitstream, the method comprising the steps of deriving a maximum allowable number of layers, and predicting the picture of the current layer, on the condition that, when a first condition is met, the value of a first syntax element specifying a second syntax element is not present in the coded video bitstream, the first condition being that the value of the maximum allowable number of layers is 1.

[0082] According to a 24th aspect, the present invention relates to a method for decoding a coded video bitstream, the method being performed by an apparatus for decoding a coded video bitstream, the method comprising the steps of obtaining the number of layers of a video bitstream, and predicting the pictures of the layers by the same values ​​of chroma format-related syntax elements when a first condition is met, which includes that the number of layers is greater than 1.

[0083] In a possible implementation of the method according to the 24th aspect itself, the method further includes the step of determining that the values ​​of the chroma format-related syntax elements of the layers are the same when the first condition is met.

[0084] In any of the preceding implementations of the 24th embodiment or possible implementations of the method according to the 24th embodiment itself, the chroma format-related syntax elements include chroma_format_idc or separate_colour_plane_flag.

[0085] In any of the preceding implementations of the 24th embodiment or in possible implementations of the method according to the 24th embodiment itself, obtaining the number of layers in a video bitstream involves parsing a syntax element (e.g., vps_max_layers_minus1) used to derive the maximum allowable number of layers in order to obtain the number of layers.

[0086] According to a 25th aspect, the present invention relates to a method for decoding a coded video bitstream, the method being performed by an apparatus for decoding a coded video bitstream, the method comprising the steps of obtaining the number of layers of a video bitstream, and predicting the pictures of the layers by the same values ​​of bit depth-related syntax elements when a first condition is met, which includes that the number of layers is greater than 1.

[0087] In a possible implementation of the method according to the 25th aspect itself, the method further includes the step of determining that the values ​​of bit-depth-related syntax elements of layers are the same when the first condition is met.

[0088] In any of the preceding implementations of the 25th embodiment or possible implementations of the method according to the 25th embodiment itself, the bit depth-related syntax element includes bit_depth_minus8.

[0089] In any of the preceding implementations of the 25th embodiment or in possible implementations of the method according to the 25th embodiment itself, obtaining the number of layers in a video bitstream includes parsing a syntax element (e.g., vps_max_layers_minus1) used to derive the maximum allowable number of layers in order to obtain the number of layers.

[0090] According to the 26th aspect, the present application relates to a decoder including a processing circuit for carrying out the methods according to the 21st to 25th aspects.

[0091] According to the 27th aspect, the present application relates to a computer program product which includes program code for performing a method according to any one of the 21st to 25th aspects when executed on a computer or processor.

[0092] According to the 28th aspect, the present application relates to a decoder comprising one or more processors and a non-temporary computer-readable storage medium coupled to the processors and storing a program for execution by the processors, wherein the decoder is configured to perform a method according to any one of the 21st to 25th aspects when executed by the processors.

[0093] According to the 29th aspect, the present application relates to a non-temporary computer-readable medium for carrying program code that, when executed by a computer device, causes the computer device to execute one of the methods of the 21st to 25th aspects.

[0094] Details of one or more embodiments are described in the accompanying drawings and the following description. Other features, purposes, and advantages will become apparent from the specification, drawings, and claims.

[0095] According to embodiments of this application, a reference layer syntax element is obtained by parsing a coded video bitstream, the value of which specifies whether the layer having index k is a direct reference layer of the layer having index i, where both i and k are integers and greater than or equal to 0, and based on the value of the reference layer syntax element, it is determined whether the layer having index j is a reference layer of the layer having index i, where the layer having index j is a reference layer of the layer having index k, where j is an integer and greater than or equal to 0, and if the condition is met, the picture of the layer having index i is predicted based on the layer having index j, the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, the condition including that the layer having index j is a reference layer of the layer having index i, and thus constraints on the format of the current layer and reference layer for inter-layer prediction are achieved, thereby simplifying the design. [Brief explanation of the drawing]

[0096] Embodiments of the present invention will be described in more detail below with reference to the attached figures and drawings. [Figure 1A] This block diagram shows an example of a video coding system configured to implement an embodiment of the present application. [Figure 1B] Block diagram shows another example of a video coding system configured to implement an embodiment of the present application. [Figure 2] This is a block diagram showing an example of a video encoder configured to implement an embodiment of the present application. [Figure 3] This is a block diagram illustrating an exemplary structure of a video decoder configured to realize an embodiment of the present application. [Figure 4] This is a block of examples of encoding or decoding devices. [Figure 5] This is a block of other examples of encoding or decoding devices. [Figure 6] This is an illustrative diagram showing scalable coding with two layers. [Figure 7] This is a schematic flowchart illustrating a method for decoding a coded video bitstream according to an embodiment of the present application. [Figure 8] This is a schematic flowchart illustrating a method for decoding a coded video bitstream according to an embodiment of the present application. [Figure 9] This is a schematic flowchart illustrating a method for decoding a coded video bitstream according to an embodiment of the present application. [Figure 10] This is a schematic flowchart illustrating a method for decoding a coded video bitstream according to an embodiment of the present application. [Figure 11] This is a schematic flowchart illustrating a method for decoding a coded video bitstream according to an embodiment of the present application. [Figure 12] This is a schematic flowchart illustrating a method for decoding a coded video bitstream according to an embodiment of the present application. [Figure 13] This is a schematic flowchart illustrating a method for encoding video according to an embodiment of the present application. [Figure 14] This is a schematic flowchart illustrating a method for encoding video according to an embodiment of the present application. [Figure 15] This is a schematic flowchart illustrating a method for encoding video according to an embodiment of the present application. [Figure 16] This is a schematic flowchart illustrating a method for encoding video according to an embodiment of the present application. [Figure 17] This is a structural diagram showing an apparatus for decoding a coded video bitstream according to an embodiment of the present application. [Figure 18]This is a structural diagram showing an apparatus for decoding a coded video bitstream according to an embodiment of the present application. [Figure 19] This is a structural diagram showing an apparatus for decoding a coded video bitstream according to an embodiment of the present application. [Figure 20] This is a structural diagram showing an apparatus for decoding a coded video bitstream according to an embodiment of the present application. [Figure 21] This is a structural diagram showing an apparatus for decoding a coded video bitstream according to an embodiment of the present application. [Figure 22] This is a structural diagram showing an apparatus for decoding a coded video bitstream according to an embodiment of the present application. [Figure 23] This is a structural diagram showing an apparatus for encoding video according to an embodiment of the present application. [Figure 24] This is a structural diagram showing an apparatus for encoding video according to an embodiment of the present application. [Figure 25] This is a structural diagram showing an apparatus for encoding video according to an embodiment of the present application. [Figure 26] This is a structural diagram showing an apparatus for encoding video according to an embodiment of the present application. [Figure 27] This is a block diagram showing an exemplary structure of a content supply system 3100 that realizes a content distribution service. [Figure 28] This is a block diagram showing the structure of an example terminal device.

[0097] In the following, unless otherwise explicitly specified, the same reference numeral indicates the same or at least functionally equivalent features. [Modes for carrying out the invention]

[0098] The following description refers to the accompanying drawings, which form part of this disclosure and illustrate, by example, specific embodiments of the invention or specific ways in which embodiments of the invention may be used. It is understood that embodiments of the invention may be used in other ways and may include structural or logical modifications not shown in the drawings. Accordingly, the following detailed description should not be taken as limiting, and the scope of the invention is defined by the appended claims.

[0099] For example, disclosure relating to a described method may also apply to a corresponding device or system configured to perform the method, and vice versa. For example, if one or more steps of a particular method are described, the corresponding device may include one or more units, e.g., functional units, for performing the steps of the described one or more methods, even if one or more such units are not explicitly described or shown in the drawings (e.g., one unit performs one or more steps, or multiple units each perform one or more of the steps). On the other hand, for example, if a particular device is described based on one or more units, e.g., functional units, the corresponding method may include one step for performing the function of one or more units, even if one or more such steps are not explicitly described or shown in the drawings (e.g., one step performs the function of one or more units, or multiple steps each perform one or more of the functions of the multiple units). Furthermore, it is understood that the various exemplary embodiments and / or features described herein may be combined with each other unless otherwise specified.

[0100] Typically, video coding refers to the processing of a sequence of pictures that make up a video or video sequence. Instead of the term “picture,” the terms “frame” or “image” may be used synonymously in the field of video coding. Video coding (or coding in general) comprises two parts: video encoding and video decoding. Video encoding is performed on the source side and typically involves processing the original video picture (e.g., by compression) to reduce the amount of data required to represent the video picture (for more efficient storage and / or transmission). Video decoding is performed on the destination side and typically involves the reverse processing compared to the encoder in order to reconstruct the video picture. Embodiments referring to “coding” a video picture (or picture in general) are understood to relate to “encoding” or “decoding” a video picture or the respective video sequence. The combination of the encoding and decoding parts is also called a codec (Coding and Decoding).

[0101] In lossless video coding, the original video picture can be reconstructed, meaning the reconstructed video picture has the same quality as the original video picture (assuming there is no transmission loss or other data loss during storage or transmission). In lossy video coding, further compression is performed, for example, by quantization, to reduce the amount of data representing the video picture, which cannot be fully reconstructed by the decoder, meaning the quality of the reconstructed video picture is lower or worse compared to the quality of the original video picture.

[0102] Several video coding standards belong to the group of “lossy hybrid video codecs” (i.e., combining spatial and temporal prediction in the sample domain with 2D transform coding to apply quantization in the transform domain). Each picture in a video sequence is typically partitioned into a set of non-overlapping blocks, and coding is typically performed at the block level. In other words, in the encoder, for example, spatial (intra-picture) prediction and / or temporal (inter-picture) prediction are used to generate predicted blocks, the predicted blocks are subtracted from the current block (the block currently being processed / to be processed) to obtain the residual block, and the residual block is transformed to quantize it in the transform domain to reduce the amount of data to be transmitted (compression), so video is typically processed, i.e., encoded, at the block (video block) level. On the other hand, in the decoder, the reverse processing compared to the encoder is applied to the encoded or compressed block to reconstruct the current block for representation. Furthermore, the encoder replicates the decoder processing loop so that both generate the same predictions (e.g., intra and inter-predictions) and / or reconstructions to process subsequent blocks, i.e., to code them.

[0103] Embodiments of the video coding system 10, video encoder 20, and video decoder 30 will be described below with reference to Figures 1 to 3.

[0104] Figure 1A is a schematic block diagram showing an exemplary coding system 10, for example, a video coding system 10 (or simply coding system 10), which may utilize the technology of the present application. The video encoder 20 (or simply encoder 20) and video decoder 30 (or simply decoder 30) of the video coding system 10 represent examples of devices that may be configured to perform the various exemplary technologies described in the present application.

[0105] As shown in Figure 1A, the coding system 10 includes a source device 12 configured to provide encoded picture data 21 to a destination device 14 for decoding, for example, encoded picture data 13.

[0106] The source device 12 includes an encoder 20 and may also include, optionally, a picture source 16, a preprocessor (or preprocessing unit) 18, for example, a picture preprocessor 18, and a communication interface or communication unit 22.

[0107] The picture source 16 may be any type of picture capture device, e.g., a camera for capturing real-world pictures, and / or any type of picture generation device, e.g., a computer graphics processor for generating computer-animated pictures, or any other type of device for acquiring and / or providing real-world pictures, computer-generated pictures (e.g., screen content, virtual reality (VR) pictures), and / or any combination thereof (e.g., augmented reality (AR) pictures). The picture source may also be any type of memory or storage for storing any of the above pictures.

[0108] In contrast to the processing performed by the preprocessor 18 and the preprocessing unit 18, the picture or picture data 17 may also be called the raw picture or raw picture data 17.

[0109] The preprocessor 18 is configured to receive (raw) picture data 17, perform preprocessing on the picture data 17, and obtain a preprocessed picture 19 or preprocessed picture data 19. The preprocessing performed by the preprocessor 18 may include, for example, cropping, color format conversion (e.g., RGB to YCbCr), color correction, or noise reduction. It is understood that the preprocessing unit 18 may be any selected component.

[0110] The video encoder 20 is configured to receive pre-processed picture data 19 and provide encoded picture data 21 (further details are described below, for example, based on Figure 2).

[0111] The communication interface 22 of the source device 12 may be configured to receive encoded picture data 21 and transmit the encoded picture data 21 (or any further processed version thereof) over the communication channel 13 to another device, for example, the destination device 14 or any other device, for storage or direct reconstruction.

[0112] The destination device 14 includes a decoder 30 (e.g., a video decoder 30), and may also include, optionally, a communication interface or communication unit 28, a post-processor 32 (or post-processing unit 32), and a display device 34.

[0113] The communication interface 28 of the destination device 14 is configured to receive encoded picture data 21 (or any further processed version thereof) from, for example, directly from the source device 12 or from any other source, for example, a storage device, for example, an encoded picture data storage device, and to provide the encoded picture data 21 to the decoder 30.

[0114] Communication interfaces 22 and 28 may be configured to transmit or receive encoded picture data 21 or encoded data 13 via a direct communication link between the source device 12 and the destination device 14, for example, via a direct wired or wireless connection, or via any type of network, for example, a wired or wireless network or a combination thereof, or any type of private and public network, or a combination thereof.

[0115] The communication interface 22 may be configured, for example, to package the encoded picture data 21 into an appropriate format, such as a packet, and / or process the encoded picture data using any type of transmit encoding or processing for transmission over a communication link or communication network.

[0116] The communication interface 28, which forms the counterpart to the communication interface 22, may be configured, for example, to receive the transmitted data and process the transmitted data using any of the corresponding types of transmission decoding or processing and / or depackaging to obtain the encoded picture data 21.

[0117] Both communication interfaces 22 and 28 may be configured as unidirectional or bidirectional communication interfaces, as indicated by the arrows in Figure 1A for the communication channel 13 pointing from source device 12 to destination device 14, for example, to send and receive messages, to set up connections, and to acknowledge and exchange any other information relating to communication links and / or data transmission, such as encoded picture data transmission.

[0118] The decoder 30 is configured to receive encoded picture data 21 and provide decoded picture data 31 or decoded picture 31 (further details are described below, for example, based on Figure 3 or Figure 5).

[0119] The post-processor 32 of the destination device 14 is configured to post-process the decoded picture data 31 (also called reconstructed picture data), for example, the decoded picture 31, to obtain post-processed picture data 33, for example, the post-processed picture 33. The post-processing performed by the post-processing unit 32 may include, for example, color format conversion (e.g., YCbCr to RGB), color correction, cropping or resampling, or any other processing to prepare the decoded picture data 31 for display by, for example, the display device 34.

[0120] The display device 34 of the destination device 14 is configured to receive the post-processed picture data 33 and, for example, display the picture to a user or viewer. The display device 34 may be or include any type of display that presents the reconstructed picture, such as an integrated or external display or monitor. The display may be or include, for example, a liquid crystal display (LCD), an organic light-emitting diode (OLED) display, a plasma display, a projector, a micro-LED display, a liquid crystal on silicon (LCoS), a digital light processor (DLP), or any other type of display.

[0121] Figure 1A shows the source device 12 and the destination device 14 as separate devices, but the device embodiments may also include the functions of both or both, the source device 12 or its corresponding function and the destination device 14 or its corresponding function. In such embodiments, the source device 12 or its corresponding function and the destination device 14 or its corresponding function may be implemented using the same hardware and / or software, or by separate hardware and / or software, or any combination thereof.

[0122] As will be apparent to those skilled in the art based on the description, the presence and (exact) division of different units or functions within the source device 12 and / or destination device 14 as shown in Figure 1A may vary depending on the actual device and application.

[0123] The encoder 20 (e.g., video encoder 20) or the decoder 30 (e.g., video decoder 30), or both the encoder 20 and the decoder 30, may be implemented via processing circuits, such as one or more microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), discrete logic, hardware, dedicated video coding, or any combination thereof, as shown in Figure 1B. The encoder 20 may be implemented via processing circuits 46 to embody various modules, as described with respect to the encoder 20 in Figure 2 and / or any other encoder system or subsystem described herein. The decoder 30 may be implemented via processing circuits 46 to embody various modules, as described with respect to the decoder 30 in Figure 3 and / or any other decoder system or subsystem described herein. The processing circuits may be configured to perform various operations, as described below. As shown in Figure 5, if the technology is partially implemented in software, the device may store instructions for the software in a suitable non-temporary computer-readable storage medium, and may execute the instructions in hardware using one or more processors to perform the technology of this disclosure. Either the video encoder 20 or the video decoder 30 may be integrated as part of a combined encoder / decoder (CODEC) within a single device, for example, as shown in Figure 1B.

[0124] The source device 12 and destination device 14 may include any of a broad range of devices, including handheld or fixed devices of any kind, such as notebook or laptop computers, mobile phones, smartphones, tablets or tablet computers, cameras, desktop computers, set-top boxes, televisions, display devices, digital media players, video game consoles, video streaming devices (such as content service servers or content distribution servers), broadcast receiver devices, broadcast transmitter devices, etc., and may or may not use any kind of operating system. In some cases, the source device 12 and destination device 14 may be equipped for wireless communication. Therefore, the source device 12 and destination device 14 may also be wireless communication devices.

[0125] In some cases, the video coding system 10 shown in Figure 1A is merely an example, and the technology of the present invention may be applied to video coding configurations (e.g., video coding or video decoding) that do not necessarily involve any data communication between the coding device and the decoding device. In other examples, the data may be retrieved from local memory, streamed over a network, etc. The video coding device may code the data and store it in memory, and / or the video decoding device may retrieve the data from memory and decode it. In some examples, coding and decoding are performed by devices that do not communicate with each other but simply code the data into memory and / or retrieve the data from memory and decode it.

[0126] For the sake of explanation, embodiments of the present invention are described herein by reference to, for example, reference software for High-Efficiency Video Coding (HEVC) or Versatile Video Coding (VVC), and next-generation video coding standards developed by the ITU-T Video Coding Experts Group (VCEG) and the Joint Collaboration Team on Video Coding (JCT-VC) of the ISO / IEC Motion Picture Experts Group (MPEG). Those skilled in the art will understand that embodiments of the present invention are not limited to HEVC or VVC.

[0127] Encoder and encoding method Figure 2 shows a schematic block diagram of an exemplary video encoder 20 configured to realize the technology of the present invention. In the example of Figure 2, the video encoder 20 includes an input 201 (or input interface 201), a residual calculation unit 204, a transformation processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse transformation processing unit 212, a reconstruction unit 214, a loop filter unit 220, a decoded picture buffer (DPB) 230, a mode selection unit 260, an entropy coding unit 270, and an output 272 (or output interface 272). The mode selection unit 260 may include an inter-prediction unit 244, an intra-prediction processing unit 254, and a partition unit 262. The inter-prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown). The video encoder 20 as shown in Figure 2 may also be called a hybrid video encoder or a video encoder with a hybrid video codec.

[0128] The residual calculation unit 204, the conversion processing unit 206, the quantization unit 208, and the mode selection unit 260 may also be referred to as forming the forward signal path of the encoder 20. On the other hand, the inverse quantization unit 210, the inverse conversion processing unit 212, the reconstruction unit 214, the buffer 216, the loop filter 220, the decoded picture buffer (DPB) 230, the inter-prediction unit 244, and the intra-prediction unit 254 may also be referred to as forming the reverse signal path of the video encoder 20, where the reverse signal path corresponds to the signal path of the decoder (see decoder 30 in Figure 3). The inverse quantization unit 210, the inverse conversion processing unit 212, the reconstruction unit 214, the loop filter 220, the decoded picture buffer (DPB) 230, the inter-prediction unit 244, and the intra-prediction unit 254 are also referred to as forming the “built-in decoder” of the video encoder 20.

[0129] Picture and picture partition (picture and block) The encoder 20 may be configured, for example, to receive a picture 17 (or picture data 17) via input 201, for example, a picture of a sequence of pictures that form a video or video sequence. The received picture or picture data may also be a preprocessing picture 19 (preprocessing picture data 19). For brevity, the following description will refer to picture 17. Picture 17 may also be called the current picture or the picture to be coded (in particular, in video coding, to distinguish the current picture from other pictures, for example, pictures encoded and / or decoded before the same video sequence, i.e., the video sequence that also contains the current picture).

[0130] A (digital) picture is, or can be thought of as, a two-dimensional array or matrix of samples having intensity values. A sample in the array may also be called a pixel (short for picture element) or pel. The number of samples in the horizontal and vertical directions (or axes) of the array or picture defines the size and / or resolution of the picture. For color representation, typically three color components are used; that is, a picture may or may contain three sample arrays. In the RGB format or color space, a picture contains corresponding red, green, and blue sample arrays. However, in video coding, each pixel is typically represented by a luminance and chrominance format or color space, e.g., YCbCr, which includes a luminance component represented by Y (sometimes L is used instead) and two chrominance components represented by Cb and Cr. The luminance (or abbreviated as luma) component Y represents brightness or gray level intensity (e.g., in a grayscale picture). On the other hand, the two chrominance (or chroma for short) components Cb and Cr represent chromaticity or color information components. Therefore, a picture in YCbCr format includes a luminance sample array of luminance sample values ​​(Y) and two chrominance sample arrays of chrominance values ​​(Cb and Cr). A picture in RGB format may be converted to or from YCbCr format, and vice versa; the process is also known as color conversion or transformation. If the picture is monochrome, the picture may include only a luminance sample array. Therefore, a picture may be, for example, a luminance sample array in a monochrome format, or two corresponding arrays of luminance samples and chroma samples in 4:2:0, 4:2:2, and 4:4:4 color formats.

[0131] Embodiments of the video encoder 20 may include a picture partition unit (not shown in Figure 2) configured to partition a picture 17 into a plurality of (typically non-overlapping) picture blocks 203. These blocks may also be called root blocks, macro blocks (H.264 / AVC), coding tree blocks (CTB), or coding tree units (CTU) (H.265 / HEVC and VVC). The picture partition unit may be configured to use the same block size for all pictures in the video sequence and for the corresponding grid that defines the block size, or to change the block size between pictures or subsets or groups of pictures and partition each picture into the corresponding block.

[0132] In a further embodiment, the video encoder may be configured to directly receive blocks 203 of picture 17, for example, one, some, or all of the blocks that make up picture 17. Picture block 203 may also be called the picture block now or the picture block to be coded.

[0133] Similar to picture 17, picture block 203 is also a two-dimensional array or matrix of samples having intensity values ​​(sample values), or can be conceived as such, but with fewer dimensions than picture 17. In other words, block 203 may contain, for example, one sample array (e.g., a luma array in the case of monochrome picture 17, or a luma or chroma array in the case of a color picture) or three sample arrays (e.g., a luma and two chroma arrays in the case of color picture 17), or any other number and / or type of arrays depending on the applied color format. The number of samples in the horizontal and vertical directions (or axes) of block 203 defines the size of block 203. Thus, the block may be, for example, an M×N (M columns × N rows) array of samples, or an M×N array of conversion coefficients.

[0134] An embodiment of the video encoder 20 shown in Figure 2 may be configured to encode the picture 17 block by block, for example, encoding and prediction may be performed for each block 203.

[0135] Embodiments of the video encoder 20, as shown in Figure 2, may be further configured to partition and / or encode a picture using slices (also called video slices), the picture may be partitioned into or encoded using one or more slices (typically non-overlapping), each slice may contain one or more blocks (e.g., CTUs) or groups of one or more blocks (e.g., tiles (H.265 / HEVC and VVC) or bricks (VVC)).

[0136] Embodiments of the video encoder 20, as shown in Figure 2, may be further configured to partition and / or encode a picture by using slice / tile groups (also called video tile groups) and / or tiles (also called video tiles), wherein the picture may be partitioned into or encoded using one or more slice / tile groups (typically non-overlapping), each slice / tile group may include, for example, one or more blocks (e.g., CTUs) or one or more tiles, each tile may be, for example, rectangular in shape and may include one or more blocks (e.g., CTUs), for example, complete or partial blocks.

[0137] Residual calculation The residual calculation unit 204 may be configured to calculate the residual block 205 (also called residual 205) by, for example, subtracting the sample value of the prediction block 265 from the sample value of the picture block 203 for each sample (for each pixel) to obtain the residual block 205 in the sample domain, based on the picture block 203 and the prediction block 265 (further details regarding the prediction block 265 are provided below).

[0138] conversion The transformation processing unit 206 may be configured to obtain transformation coefficients 207 in the transformation domain by applying a transformation, such as a discrete cosine transform (DCT) or discrete sine transform (DST), to the sample values ​​of the residual block 205. The transformation coefficients 207 are also called transformation residual coefficients and may represent the residual block 205 in the transformation domain.

[0139] The conversion processing unit 206 may be configured to apply an integer approximation of DCT / DST, such as the conversion specified for H.265 / HEVC. Compared to the orthogonal DCT conversion, such an integer approximation is typically scaled by a specific factor. Further scaling factors are applied as part of the conversion process to maintain the norm of the residual blocks processed by the forward and inverse conversions. The scaling factors are typically selected based on specific constraints, such as the scaling factor being a power of 2 for the shift operation, the bit depth of the conversion coefficients, and the trade-off between precision and implementation cost. A specific scaling factor may be specified, for example, for the inverse conversion by the inverse conversion processing unit 212 (and, for example, the corresponding inverse conversion by the inverse conversion processing unit 312 in the video decoder 30), and a corresponding scaling factor may be specified accordingly, for example, for the forward conversion by the conversion processing unit 206 in the encoder 20.

[0140] Embodiments of the video encoder 20 (each a conversion processing unit 206) may be configured to output conversion parameters, for example, the type of conversion or multiple conversions, which are encoded or compressed, for example, directly or via the entropy coding unit 270, so that, for example, the video decoder 30 may receive and use the conversion parameters for decoding.

[0141] quantization The quantization unit 208 may be configured to quantize the transformation coefficient 207 by, for example, applying scalar quantization or vector quantization to obtain the quantized coefficient 209. The quantized coefficient 209 may also be called the quantized transformation coefficient 209 or the quantized residual coefficient 209.

[0142] The quantization process may reduce the bit depth associated with some or all of the conversion coefficients 207. For example, n-bit conversion coefficients may be truncated to m-bit conversion coefficients during quantization, where n is greater than m. The degree of quantization may be changed by adjusting the quantization parameter (QP). For example, in scalar quantization, different scaling may be applied to achieve finer or coarser quantization. Smaller quantization step sizes correspond to finer quantization, while larger quantization step sizes correspond to coarser quantization. Applicable quantization steps may be indicated by the quantization parameter (QP). The quantization parameter may be, for example, an index to a given set of applicable quantization step sizes. For example, a small quantization parameter may correspond to finer quantization (smaller quantization step size), a large quantization parameter may correspond to coarser quantization (larger quantization step size), and vice versa. Quantization may involve division by the quantization step size, and the corresponding and / or inverse dequantization by the inverse quantization unit 210 may involve multiplication by the quantization step size. Some standards, e.g., embodiments by HEVC, may be configured to use quantization parameters to determine the quantization step size. Generally, the quantization step size may be calculated based on the quantization parameters using a fixed-point approximation of the equations involving division. Further scaling factors for quantization and dequantization may be introduced to restore the norm of the residual block, which may be modified due to the scaling used in the fixed-point approximation of the equations for the quantization step size and quantization parameters. In one exemplary implementation, the scaling of the inverse transform and dequantization may be combined. Alternatively, a customized quantization table may be used and signaled, for example, from encoder to decoder in a bitstream. Quantization is an irreversible operation, and losses increase with increasing quantization step size.

[0143] Embodiments of the video encoder 20 (each a quantization unit 208) may be configured to output a quantization parameter (QP) which is encoded, for example, directly or via an entropy coding unit 270, so that, for example, the video decoder 30 may receive and apply the quantization parameter for decoding.

[0144] inverse quantization The inverse quantization unit 210 is configured to obtain the de-quantized coefficients 211 by applying the inverse of the quantization scheme applied by the quantization unit 208 to the quantized coefficients, for example, by applying the inverse of the quantization scheme applied by the quantization unit 208, based on or using the same quantization step size as the quantization unit 208. The de-quantized coefficients 211 are also called de-quantized residual coefficients 211 and may correspond to the transformation coefficients 207, although they are typically not identical to the transformation coefficients due to quantization losses.

[0145] Inverse Transform The inverse transformation processing unit 212 is configured to obtain a reconstructed residual block 213 (or the corresponding antiquantized coefficient 213) in the sample domain by applying the inverse transformation of the transformation applied by the transformation processing unit 206, for example, the inverse discrete cosine transform (DCT) or the inverse discrete sine transform (DST), or other inverse transformations. The reconstructed residual block 213 may also be called the transformation block 213.

[0146] Reconstruction The reconstruction unit 214 (e.g., an adder or totaler 214) is configured to obtain the reconstructed block 215 in the sample domain by adding the transformed block 213 (i.e., the reconstructed residual block 213) to the prediction block 265, for example by adding the sample values ​​of the reconstructed residual block 213 and the prediction block 265 sample by sample.

[0147] filtering The loop filter unit 220 (or simply "loop filter" 220) is configured to filter the reconstructed block 215 to obtain the filtered block 221, or more generally, to filter the reconstructed sample to obtain the filtered sample value. The loop filter unit is configured, for example, to smooth pixel transitions or to improve video quality. The loop filter unit 220 may include a deblocking filter, a sample-adaptive offset (SAO) filter, or one or more other filters, such as an adaptive loop filter (ALF), a noise suppression filter (NSF), or any combination thereof. In one example, the loop filter unit 220 may include a deblocking filter, an SAO filter, and an ALF filter. The order of the filtering process may be deblocking filter, SAO, and ALF. In another example, a process called luma mapping with chroma scaling (LMCS) (i.e., adaptive in-loop reshaper) is added. This process is performed before deblocking. In other examples, the deblocking filter process may also be applied to internal subblock edges, such as affine subblock edges, ATMVP subblock edges, sub-block transform (SBT) edges, and intra-subpartition (ISP) edges. Although the loop filter unit 220 is shown in Figure 2 as an in-loop filter, in other configurations, the loop filter unit 220 may be implemented as a post-loop filter. The filtered block 221 may also be called the filtered reconfigured block 221.

[0148] Embodiments of the video encoder 20 (each a loop filter unit 220) may be configured to output loop filter parameters (such as SAO filter parameters, ALF filter parameters, or LMCS parameters) which are encoded, for example, directly or via the entropy coding unit 270, so that, for example, the decoder 30 may receive and apply the same loop filter parameters or the respective loop filters for decoding.

[0149] Decode picture buffer The decoded picture buffer (DPB) 230 may be a memory that stores a reference picture or generally reference picture data for encoding video data by the video encoder 20. The DPB 230 may be formed from any of various memory devices, such as dynamic random access memory (DRAM) including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. The decoded picture buffer (DPB) 230 may be configured to store one or more filtered blocks 221. The decoded picture buffer 230 may be further configured to store the same current picture or a different picture, for example, other previously filtered blocks of a previously reconstructed picture, for example, a previously reconstructed and filtered block 221, for example, for interpretation, it may provide a fully reconstructed, i.e., decoded picture (and corresponding reference blocks and samples) and / or a partially reconstructed current picture (and corresponding reference blocks and samples). The decoded picture buffer (DPB) 230 may also be configured to store one or more unfiltered reconstructed blocks 215, or generally, for example, if the reconstructed blocks 215 are not filtered by the loop filter unit 220, unfiltered reconstructed samples, or other further processed versions of any of the reconstructed blocks or samples.

[0150] Mode selection (partition and prediction) The mode selection unit 260 includes a partition unit 262, an inter-prediction unit 244, and an intra-prediction unit 254, and is configured to receive or acquire original picture data, e.g., original block 203 (current block 203 of current picture 17), and reconstructed picture data, e.g., filtered and / or unfiltered reconstructed samples or blocks from the same (current) picture and / or one or more previously decoded pictures, e.g., from the decoded picture buffer 230 or other buffers (e.g., line buffers not shown). The reconstructed picture data is used as reference picture data for predictions, e.g., inter-prediction or intra-prediction, to acquire prediction blocks 265 or predictors 265.

[0151] The mode selection unit 260 may be configured to determine or select a partition (including no partition) for the current block prediction mode and a prediction mode (e.g., intra or inter-prediction mode), and to generate a corresponding prediction block 265 to be used for calculating the residual block 205 and for reconstructing the reconstructed block 215.

[0152] Embodiments of the mode selection unit 260 may be configured to select partition and prediction modes (for example, from those supported or available by the mode selection unit 260) that provide the best fit, or in other words, minimum residual (minimum residual meaning better compression for transmission or storage) or minimum signaling overhead (minimum signaling overhead meaning better compression for transmission or storage), or that consider or balance both. The mode selection unit 260 may be configured to determine the partition and prediction modes based on rate distortion optimization (RDO), i.e., to select a prediction mode that provides the minimum rate distortion. In this context, terms such as “best,” “minimum,” and “optimal” do not necessarily refer to an overall “best,” “minimum,” and “optimal,” but may refer to termination or selection criteria such as a value above or below a threshold, or the satisfaction of other constraints that result in a potentially “suboptimal selection” but reduce complexity and processing time.

[0153] In other words, the partition unit 262 may be configured to partition pictures from a video sequence into a sequence of coding tree units (CTUs), and the CTU 203 may be further partitioned into smaller block partitions or subblocks (which also form blocks) by repeatedly using, for example, quad-tree partitioning (QT), binary partitioning (BT), or triple-tree partitioning (TT), or any combination thereof, for example, for each block partition or subblock, and the mode selection includes selecting the tree structure of the partitioned block 203, and the prediction mode is applied to each block partition or subblock.

[0154] The following describes in more detail the partitioning (by the partition unit 260, for example) and prediction (by the inter-prediction unit 244 and intra-prediction unit 254) processes performed by the exemplary video encoder 20.

[0155] partition The partition unit 262 may be configured to partition pictures from a video sequence into a sequence of coding tree units (CTUs), which may partition (or divide) the coding tree units (CTUs) 203 into smaller partitions, such as smaller blocks of a square or rectangular size. For a picture having three sample sequences, the CTU consists of N×N blocks of luma samples, along with two corresponding blocks of chroma samples. The maximum allowable size of luma blocks in a CTU is specified as 128×128 in the developing Versatile Video Coding (VVC), but may be specified as a value other than 128×128 in the future, such as 256×256. The CTUs of a picture may be clustered / grouped as slice / tile groups, tiles, or bricks. A tile covers a rectangular area of ​​the picture, and a tile can be divided into one or more bricks. A brick consists of multiple CTU rows within a tile. A tile that is not partitioned into multiple bricks can be called a brick. However, a brick is a true subset of a tile and is not called a tile. There are two modes of tile groups supported by VVC: raster scan slice / tile group mode and rectangular slice mode. In raster scan tile group mode, a slice / tile group contains a sequence of tiles in a tile raster scan of a picture. In rectangular slice mode, a slice contains a number of bricks of a picture that collectively form a rectangular region of the picture. The bricks within a rectangular slice are in order of the slice's brick raster scan. These smaller blocks (which may also be called subblocks) may be further partitioned into even smaller partitions.This is also called tree partitioning or hierarchical tree partitioning. For example, the root block at root tree level 0 (hierarchical level 0, depth 0) may be recursively partitioned into, for example, two or more blocks at the next lower tree level, for example, a node at tree level 1 (hierarchical level 1, depth 1). These blocks may then be partitioned again into, for example, two or more blocks at the next lower tree level, for example, tree level 2 (hierarchical level 2, depth 2), until the partitioning ends, for example, because a termination criterion is met, for example, because the maximum tree depth or minimum block size has been reached. Blocks that are not further partitioned are also called leaf blocks or leaf nodes of the tree. A tree that uses partitioning into two partitions is called a binary tree (BT), a tree that uses partitioning into three partitions is called a ternary tree (TT), and a tree that uses partitioning into four partitions is called a quad tree (QT).

[0156] For example, a coding tree unit (CTU) may be or include a CTB of a luma sample, two corresponding CTBs of a chroma sample of a picture having three sample sequences, or a CTB of a sample of a picture coded using a syntax structure used to code a monochrome picture or three separate color planes and samples. Correspondingly, a coding tree block (CTB) may be an N×N block of samples for some value N, such that the division of components into a CTB is a partition. A coding unit (CU) may be or include a coding block of a luma sample, two corresponding coding blocks of a chroma sample of a picture having three sample sequences, or a coding block of a sample of a picture coded using a syntax structure used to code a monochrome picture or three separate color planes and samples. Correspondingly, a coding block (CB) may be an M×N block of samples for some values ​​M and N, such that the division of a CTB into a coding block is a partition.

[0157] For example, in an embodiment using HEVC, a coding tree unit (CTU) may be partitioned into CUs by using a quadtree structure, which is represented as a coding tree. The decision of whether to code a picture region using interpicture (time) prediction or intrapicture (spatial) prediction is made at the leaf CU level. Each leaf CU can be further partitioned into one, two, or four PUs, according to the PU partitioning type. Within a single PU, the same prediction process is applied, and relevant information is sent to the decoder for each PU. After obtaining residual blocks by applying the prediction process based on the PU partitioning type, the leaf CU can be partitioned into transform units (TUs) according to other quadtree structures similar to the coding tree for the CU.

[0158] For example, in an embodiment of the latest video coding standard currently under development called Versatile Video Coding (VVC), a combined quadtree nested multitype tree using bipartite and tripartite segmentation structures is used, for example, to partition coding tree units. In the coding tree structure within a coding tree unit, the CU can have either a square or rectangular shape. For example, a coding tree unit (CTU) is first partitioned by a quadtree. Then, the quadtree leaf nodes can be further partitioned by a multitype tree structure. There are four types of partitioning for the multitype tree structure: vertical bipartite (SPLIT_BT_VER), horizontal bipartite (SPLIT_BT_HOR), vertical tripartite (SPLIT_TT_VER), and horizontal tripartite (SPLIT_TT_HOR). The multitype tree leaf nodes are called coding units (CUs), and this segmentation is used for prediction and transformation processing without further partitioning, as long as the CU is not too large for the maximum transformation length. This means that, in most cases, CU, PU, ​​and TU have the same block size in a quadtree with a nested multitype tree coding block structure. Exceptions occur when the maximum supported transformation length is smaller than the width or height of the CU's color component. VVC has developed a unique signaling mechanism for partition information in quadtrees with a nested multitype tree coding tree structure. In this signaling mechanism, the coding tree unit (CTU) is treated as the root of the quadtree and is first partitioned by the quadtree structure. Then, each quadtree leaf node (if large enough to allow) is further partitioned by the multitype tree structure.In a multi-type tree structure, a first flag (mtt_split_cu_flag) is signaled to indicate whether a node is further partitioned, and if so, a second flag (mtt_split_cu_vertical_flag) is signaled to indicate the direction of the partition, and then a third flag (mtt_split_cu_binary_flag) is signaled to indicate whether the partition is bipartite or tripartite. Based on the values ​​of mtt_split_cu_vertical_flag and mtt_split_cu_binary_flag, the multi-type tree partitioning mode (MttSplitMode) of the CU can be derived by the decoder based on a predetermined rule or table. As shown in Figure 6, in certain designs, such as 64x64 lumar blocks and 32x32 chroma pipeline designs in a VVC hardware decoder, TT partitioning is prohibited when either the width or height of the lumar coding block is greater than 64. TT partitioning is also prohibited if either the width or height of the chromacoding block is greater than 32. The pipeline design divides the picture into virtual pipeline data units (VPDUs), which are defined as non-overlapping units within the picture. In hardware decoders, consecutive VPDUs are processed simultaneously by multiple pipeline stages. Since the VPDU size is approximately proportional to the buffer size in most pipeline stages, it is important to keep the VPDU size small. In most hardware decoders, the VPDU size can be set to the maximum transform block (TB) size. However, in VVCs, ternary tree (TT) and binary tree (BT) partitioning can lead to an increase in VPDU size.

[0159] Furthermore, it should be noted that when a portion of a tree node block extends beyond the lower or right picture boundary, the tree node block is forced to split until all samples of all coded CUs are located within the picture boundary.

[0160] For example, the Intra Sub-Partitions (ISP) tool may divide a single intra-prediction block into two or four sub-partitions vertically or horizontally, depending on the block size.

[0161] In one example, the mode selection unit 260 of the video encoder 20 may be configured to perform any combination of the partitioning techniques described herein.

[0162] As described above, the video encoder 20 is configured to determine or select the best or most optimal prediction mode from a set of prediction modes (for example, a predetermined set). The set of prediction modes may include, for example, an intra-prediction mode and / or an inter-prediction mode.

[0163] Intra Prediction The set of intra-prediction modes may include 35 different intra-prediction modes, e.g., DC (or average) mode and non-directional modes such as planar mode, or directional modes such as those defined in HEVC, or it may include 67 different intra-prediction modes, e.g., DC (or average) mode and non-directional modes such as planar mode, or directional modes such as those defined for VVC. As an example, some conventional angular intra-prediction modes are adaptively replaced by wide-angle intra-prediction modes for non-square blocks, such as those defined in VVC. As another example, to avoid partitioning for DC prediction, only the long side is used to calculate the average for non-square blocks. The results of planar mode intra-prediction may be further modified by a position-dependent intra-prediction combination (PDPC) method.

[0164] The intra-prediction unit 254 is configured to use reconfigured samples of adjacent blocks of the same current picture to generate an intra-prediction block 265 according to a certain intra-prediction mode from a set of intra-prediction modes.

[0165] The intra-prediction unit 254 (or generally the mode selection unit 260) is further configured to output intra-prediction parameters (or generally information indicating the selected intra-prediction mode for a block) to the entropy coding unit 270 in the form of syntax elements 226 for inclusion in the coded picture data 21, so that, for example, the video decoder 30 may receive and use the prediction parameters for decoding.

[0166] Interpretation The set of interpretation modes (or possible ones) depends on the available reference picture (i.e., a previous, at least partially decoded picture stored in DBP230) and other interpretation parameters, such as whether the entire reference picture is used to search for the best-fitting reference block, or only a portion of the reference picture, such as the search window area around the current block's region, and / or whether pixel interpolation, such as half / semi-per, quarter-per and / or 1 / 16-per interpolation, is applied.

[0167] In addition to the prediction modes described above, skip mode, direct mode, and / or other interpretation modes may be applied.

[0168] For example, in extended merge prediction, the merge candidate list for such modes consists of the following five types of candidates, in order: spatial MVP from spatially adjacent CUs, temporal MVP from CUs at the same location, history-based MVP from a FIFO table, pair-average MVP, and zero MV. Furthermore, to improve the accuracy of the MV in the merge mode, decoder-side motion vector refinement (DMVR) based on bilateral matching may be applied. Merge mode with MVD (MMVD) derives from merge mode with motion vector difference (MVD). The MMVD flag is signaled immediately after the skip and merge flags are sent to specify whether the MMVD mode is used for a CU. Furthermore, an adaptive motion vector resolution (AMVR) scheme at the CU level may be applied. AMVR allows the MVD of a CU to be coded with different accuracies. The MVD of the current CU can be adaptively selected depending on the prediction mode for the current CU. When a CU is coded in merge mode, the combined inter / intra prediction (CIIP) mode may be applied to the current CU. To obtain the CIIP prediction, a weighted average of the inter and intra prediction signals is performed. In affine motion compensation prediction, the affine motion field of a block is described by motion information of two control points (4 parameters) or three control point motion vectors (6 parameters). Sub-block-based temporal motion vector prediction (SbTMVP) is similar to temporal motion vector prediction (TMVP) in HEVC, but predicts the motion vector of a subCU within the current CU.Bidirectional optical flow (BDOF), formerly known as BIO, is a simpler version requiring significantly less computation, particularly in terms of the number of multiplications and the size of the multipliers. In triangular partition mode, the CU is evenly divided into two triangular partitions using either diagonal or off-diagonal partitioning. Furthermore, the bidirectional prediction mode is extended beyond simple averaging to allow for a weighted average of the two prediction signals.

[0169] The interpretation unit 244 may include a motion estimation (ME) unit and a motion compensation (MC) unit (neither of which are shown in Figure 2). The motion estimation unit may be configured to receive or acquire, for motion estimation, a picture block 203 (the current block 203 of the current picture 17) and a decoded picture 231, or at least one or more previously reconstructed blocks, for example, one or more other / different previously reconstructed blocks of a decoded picture 231. For example, a video sequence may include a current picture and a previous decoded picture 231, or in other words, the current picture and the previous decoded picture 231 may be part of or form part of a sequence of pictures that make up the video sequence.

[0170] The encoder 20 may be configured, for example, to select a reference block from multiple reference blocks of the same or different pictures of multiple other pictures, and to provide the motion estimation unit with an offset (spatial offset) between the reference picture (or reference picture index) and / or the position (x,y coordinates) of the reference block and the position of the current block as an interpretation parameter. This offset is also called a motion vector (MV).

[0171] The motion compensation unit is configured to acquire, for example, interprediction parameters, and perform interprediction based on or using the interprediction parameters to acquire interprediction block 265. Motion compensation performed by the motion compensation unit may include fetching or generating prediction blocks based on the motion / block vector determined by motion estimation, and possibly performing interpolation to sub-pixel precision. Interpolation filtering may generate further pixel samples from known pixel samples, thus potentially increasing the number of candidate prediction blocks that can be used to code picture blocks. Now, upon receiving the motion vector of a picture block, the motion compensation unit may find the prediction block pointed to by the motion vector in one of the reference picture lists.

[0172] The motion compensation unit may also generate syntax elements associated with blocks and video slices for use by the video decoder 30 when decoding picture blocks of video slices. In addition to or as an alternative to slices and their respective syntax elements, tile groups and / or tiles and their respective syntax elements may be generated or used.

[0173] Entropy coding The entropy coding unit 270 is configured to obtain encoded picture data 21 that can be output via output 272 in the form of an encoded bitstream 21, for example, by applying or bypassing (uncompressing) an entropy coding algorithm or scheme (e.g., variable length coding (VLC) scheme, context adaptive VLC (CAVLC) scheme, arithmetic coding scheme, binarization, context adaptive binary arithmetic coding (CABAC) scheme, syntax-based context-adaptive binary arithmetic coding (SBAC) scheme, probability interval partitioning entropy (PIPE) coding scheme, or other entropy coding methods or techniques) to the quantized coefficients 209, inter-prediction parameters, intra-prediction parameters, loop filter parameters and / or other syntax elements, for example, an encoded picture data 21 that can be output via output 272 in the form of an encoded bitstream 21, so that, for example, a video decoder 30 may receive and use the parameters for decoding. The encoded bitstream 21 may be transmitted to the video decoder 39, or it may be stored in memory for later transmission or retrieval by the video decoder 30.

[0174] Other structural variations of the video encoder 20 can be used to encode video streams. For example, a non-conversion-based encoder 20 can directly quantize the residual signal for a given block or frame without a conversion processing unit 206. In other implementations, the encoder 20 may have a quantization unit 208 and an inverse quantization unit 210 coupled into a single unit.

[0175] Decoder and decoding method Figure 3 shows an example of a video decoder 30 configured to realize the technology of the present invention. The video decoder 30 is configured to receive encoded picture data 21 (e.g., encoded bitstream 21) encoded by, for example, the encoder 20, in order to obtain a decoded picture 331. The encoded picture data or bitstream includes information for decoding the encoded picture data, for example, data representing picture blocks and associated syntax elements of an encoded video slice (and / or tile group or tile).

[0176] In the example in Figure 3, the decoder 30 includes an entropy decoding unit 304, an inverse quantization unit 310, an inverse transformation processing unit 312, a reconstruction unit 314 (e.g., a totalizer 314), a loop filter 320, a decoded picture buffer (DBP) 330, a mode application unit 360, an inter-prediction unit 344, and an intra-prediction unit 354. The inter-prediction unit 344 may be or may include a motion compensation unit. In some examples, the video decoder 30 may perform a decoding path that is generally the reverse of the encoding path described for the video encoder 100 from Figure 2.

[0177] As described with respect to encoder 20, the inverse quantization unit 210, inverse processing unit 212, reconstruction unit 214, loop filter 220, decoded picture buffer (DPB) 230, inter-prediction unit 344, and intra-prediction unit 354 may also be called the “internal decoder” of video encoder 20. Thus, the inverse quantization unit 310 may be functionally identical to the inverse quantization unit 110, the inverse processing unit 312 may be functionally identical to the inverse processing unit 212, the reconstruction unit 314 may be functionally identical to the reconstruction unit 214, the loop filter 320 may be functionally identical to the loop filter 220, and the decoded picture buffer 330 may be functionally identical to the decoded picture buffer 230. Therefore, the descriptions provided for each unit and function of video encoder 20 apply correspondingly to each unit and function of video decoder 30.

[0178] Entropy decoding The entropy decoding unit 304 is configured to parse the bitstream 21 (or generally the encoded picture data 21) and, for example, perform entropy decoding on the encoded picture data 21 to obtain, for example, quantized coefficients 309 and / or decoded coding parameters (not shown in Figure 3), such as inter-prediction parameters (e.g., reference picture index and motion vector), intra-prediction parameters (e.g., intra-prediction mode or index), transformation parameters, quantization parameters, loop filter parameters, and / or other syntax elements. The entropy decoding unit 304 may be configured to apply a decoding algorithm or scheme corresponding to an encoding scheme such as those described with respect to the entropy coding unit 270 of the encoder 20. The entropy decoding unit 304 may be further configured to provide the inter-prediction parameters, intra-prediction parameters, and / or other syntax elements to the mode application unit 360 and to provide other parameters to other units of the decoder 30. The video decoder 30 may receive video slice-level and / or video block-level syntax elements. In addition to or as an alternative to slices and their respective syntax elements, tile groups and / or tiles and their respective syntax elements may be received and / or used.

[0179] inverse quantization The inverse quantization unit 310 may be configured to receive quantization parameters (QP, quantization parameter) (or information generally related to inverse quantization) and quantized coefficients from encoded picture data 21 (for example, by parsing and / or decoding by an entropy decoding unit 304), and to apply inverse quantization to the decoded quantized coefficients 309 based on the quantization parameters to obtain de-quantized coefficients 311, which may also be called transformed coefficients 311. The inverse quantization process may include using quantization parameters determined by the video encoder 20 for each video block in a video slice (or tile or tile group) to determine the degree of quantization and the degree of inverse quantization to be applied.

[0180] Inverse Transform The inverse transform processing unit 312 may be configured to receive the dequantized coefficients 311, also called the transform coefficients 311, and to apply a transform to the dequantized coefficients 311 in order to obtain the reconstructed residual block 213 in the sample domain. The reconstructed residual block 213 may also be called the transform block 313. The transform may be an inverse transform, such as an inverse DCT, inverse DST, inverse integer transform, or a conceptually similar inverse transform process. The inverse transform processing unit 312 may be further configured to receive transform parameters or corresponding information from the encoded picture data 21 (for example, by parsing and / or decoding by the entropy decoding unit 304) to determine the transform to be applied to the dequantized coefficients 311.

[0181] Reconstruction The reconstruction unit 314 (for example, an adder or totalizer 314) may be configured to obtain the reconstructed block 315 in the sample domain by adding the reconstructed residual block 313 to the prediction block 365, for example by adding the sample value of the reconstructed residual block 313 to the sample value of the prediction block 365.

[0182] filtering The loop filter unit 320 (either within or after the coding loop) is configured to filter the reconstructed block 315 to obtain the filtered block 321, for example, to smooth pixel transitions or to improve video quality. The loop filter unit 320 may include one or more loop filters, such as a deblocking filter, a sample-adaptive offset (SAO) filter, or one or more other filters, such as an adaptive loop filter (ALF), a noise suppression filter (NSF), or any combination thereof. In one example, the loop filter unit 220 may include a deblocking filter, an SAO filter, and an ALF filter. The order of the filtering process may be deblocking filter, SAO, and ALF. In another example, a process called luma mapping with chroma scaling (i.e., adaptive in-loop reshaper) is added. This process is performed before deblocking. In other examples, the deblocking filter process may also be applied to internal subblock edges, such as affine subblock edges, ATMVP subblock edges, sub-block transform (SBT) edges, and intra-subpartition (ISP) edges. Although the loop filter unit 320 is shown as an in-loop filter in Figure 3, in other configurations, the loop filter unit 320 may be implemented as a post-loop filter.

[0183] Decode picture buffer The decoded video block 321 of the picture is then stored in the decoded picture buffer 330, which stores the decoded picture 331 as a reference picture for later motion compensation for other pictures and / or for output of their respective displays.

[0184] The decoder 30 is configured to output a decoded picture 331, for example, via output 332, for presentation or viewing by the user.

[0185] prediction The inter-prediction unit 344 may be identical to the inter-prediction unit 244 (in particular, the motion compensation unit), and the intra-prediction unit 354 may be functionally identical to the inter-prediction unit 254, and they perform partition or partition decisions and predictions based on the respective information received from the partition and / or prediction parameters or encoded picture data 21 (for example, by parsing and / or decoding by the entropy decoding unit 304). The mode application unit 360 may be configured to perform predictions (intra or inter-predictions) block by block based on the reconstructed picture, block or each (filtered or unfiltered) sample to obtain a predicted block 365.

[0186] When a video slice is coded as an intra-coded (I) slice, the intra-prediction unit 354 of the mode application unit 360 is configured to generate a prediction block 365 for the picture block of the current video slice based on the signaled intra-prediction mode and data from blocks decoded before the current picture. When a video picture is coded as an intercoded (i.e., B or P) slice, the inter-prediction unit 344 (e.g., motion compensation unit) of the mode application unit 360 is configured to generate a prediction block 365 for the video block of the current video slice based on motion vectors and other syntax elements received from the entropy decoding unit 304. In inter-prediction, the prediction block may be generated from one of the reference pictures in one of the reference picture lists. The video decoder 30 may configure the reference frame list, list 0 and list 1 using default configuration techniques based on the reference pictures stored in the DPB 330. The same or similar may apply to embodiments that use tile groups (e.g., video tile groups) and / or tiles (e.g., video tiles) in addition to or as an alternative to slices (e.g., video slices), for example, video may be coded using I, P, or B tile groups and / or tiles.

[0187] The mode-applying unit 360 is configured to determine prediction information for video blocks in the current video slice by parsing motion vectors or related information and other syntax elements, and uses the prediction information to generate prediction blocks for the current video block being decoded. For example, the mode-applying unit 360 uses some of the received syntax elements to determine the prediction mode (e.g., intra or inter-prediction) used to code the video blocks in the video slice, the inter-prediction slice type (e.g., B-slice, P-slice, or GPB-slice), configuration information for one or more of the slice's reference picture lists, the motion vector for each inter-coded video block in the slice, the inter-prediction state for each inter-coded video block in the slice, and other information for decoding the video blocks in the current video slice. The same or similar may apply to, or thereafter, embodiments that use tile groups (e.g., video tile groups) and / or tiles (e.g., video tiles) in addition to or as an alternative to slices (e.g., video slices), for example, video may be coded using I, P, or B tile groups and / or tiles.

[0188] Embodiments of the video decoder 30, as shown in Figure 3, may be configured to partition and / or decode a picture using slices (also called video slices), the picture may be partitioned into one or more slices (typically non-overlapping) or decoded using such slices, each slice may contain one or more blocks (e.g., CTUs) or groups of one or more blocks (e.g., tiles (H.265 / HEVC and VVC) or bricks (VVC)).

[0189] Embodiments of the video decoder 30, as shown in Figure 3, may be configured to partition and / or decode a picture using slice / tile groups (also called video tile groups) and / or tiles (also called video tiles), wherein the picture may be partitioned into one or more (typically non-overlapping) slice / tile groups or decoded using them, each slice / tile group may include, for example, one or more blocks (e.g., CTUs) or one or more tiles, each tile may be, for example, rectangular in shape and may include one or more blocks (e.g., CTUs), for example, complete or partial blocks.

[0190] Other variations of the video decoder 30 can be used to decode encoded picture data 21. For example, the decoder 30 can generate an output video stream without a loop filter unit 320. For example, a non-transformation-based decoder 30 can directly dequantize the residual signal for a particular block or frame without an inverse transformation unit 312. In other implementations, the video decoder 30 may have an inverse quantization unit 310 and an inverse transformation unit 312 coupled into a single unit.

[0191] It should be understood that in encoder 20 and decoder 30, the processing result of the current step may be further processed and then output to the next step. For example, after interpolation filtering, motion vector derivation, or loop filtering, further operations such as clipping or shifting may be performed on the processing result of interpolation filtering, motion vector derivation, or loop filtering.

[0192] It should be noted that further operations may be applied to the currently derived motion vectors of a block (including, but not limited to, control point motion vectors in affine mode, subblock motion vectors in affine, planar, and ATMVP modes, time motion vectors, etc.). For example, the value of a motion vector is constrained to a predetermined range according to its representation bits. If the representation bits of a motion vector are bitDepth, the range is -2^(bitDepth-1) to 2^(bitDepth-1)-1, where "^" means exponentiation. For example, if bitDepth is set to equal 16, the range is -32768 to 32767, and if bitDepth is set to equal 18, the range is -131072 to 131071. For example, the value of a derived motion vector (e.g., the MV of four 4x4 subblocks in one 8x8 block) is constrained so that the maximum difference between the integer parts of the MVs of the four 4x4 subblocks is not greater than N pixels, such as not being greater than 1 pixel. Here, we provide two methods for constraining the motion vector according to bitDepth.

[0193] Figure 4 is a schematic diagram of a video coding device 400 according to an embodiment of the present disclosure. The video coding device 400 is suitable for implementing embodiments of the disclosure described herein. In the embodiment, the video coding device 400 may be a decoder such as the video decoder 30 in Figure 1A or an encoder such as the video encoder 20 in Figure 1A.

[0194] The video coding device 400 includes an inlet port 410 (or input port 410) and a receiver unit (Rx) 420 for receiving data, a processor, logic unit, or central processing unit (CPU) 430 for processing data, a transmitter unit (Tx) 440 and an exit port 450 (or output port 450) for transmitting data, and memory 460 for storing data. The video coding device 400 may also include optical-to-electrical (OE) and electrical-to-optical (EO) components coupled to the inlet port 410, receiver unit 420, transmitter unit 440, and exit port 450 for the exit or input of optical or electrical signals.

[0195] The processor 430 is implemented by hardware and software. The processor 430 may be implemented as one or more CPU chips, cores (e.g., a multi-core processor), FPGAs, ASICs, and DSPs. The processor 430 communicates with the input port 410, the receiver unit 420, the transmitter unit 440, the output port 450, and the memory 460. The processor 430 includes a coding module 470. The coding module 470 implements the embodiments of the disclosure described above. For example, the coding module 470 implements, processes, prepares, or provides various coding operations. Thus, what is included in the coding module 470 provides a substantial improvement to the functionality of the video coding device 400, resulting in the conversion of the video coding device 400 to different states. Alternatively, the coding module 470 is implemented as instructions stored in the memory 460 and executed by the processor 430.

[0196] Memory 460 may include one or more disks, tape drives, and solid-state drives, and may be used as an overflow data storage device for storing such programs when they are selected for execution and for storing instructions and data read during program execution. Memory 460 may be, for example, volatile and / or non-volatile, and may be read-only memory (ROM), random access memory (RAM), ternary content-addressable memory (TCAM), and / or static random-access memory (SRAM).

[0197] Figure 5 is a simplified block diagram of a device 500 which may be used as one or both of the source device 12 and destination device 14 from Figure 1 according to an exemplary embodiment.

[0198] The processor 502 within the device 500 may be a central processing unit. Alternatively, the processor 502 may be any other type of device, or multiple devices, that currently exist or may be developed in the future, capable of manipulating or processing information. The implementation of the disclosure can be carried out with a single processor, e.g., processor 502, as shown in the figure, but advantages in speed and efficiency can be achieved by using more than one processor.

[0199] The memory 504 within the device 500 can be, in implementation, a read-only memory (ROM) device or a random access memory (RAM) device. Any other suitable type of storage device can be used as memory 504. Memory 504 may contain code and data 506 accessed by the processor 502 using the bus 512. Memory 504 may further contain an operating system 508 and an application program 510, the application program 510 including at least one program that enables the processor 502 to perform the method described herein. For example, the application program 510 may include applications 1 to N, further including a video coding application that performs the method described herein.

[0200] The device 500 may also include one or more output devices, such as a display 518. The display 518 may, in one example, be a touch-sensitive display that combines a display with a touch-sensitive element capable of sensing touch input. The display 518 can be coupled to the processor 502 via the bus 512.

[0201] Although shown here as a single bus, the bus 512 of device 500 can consist of multiple buses. Furthermore, the secondary storage 514 can be directly coupled to other components of device 500 or accessed via a network, and may include a single integrated unit such as a memory card or multiple units such as multiple memory cards. Thus, device 500 can be implemented in a wide range of configurations.

[0202] Scalable coding Scalable coding includes quality-scalable (PSNR-scalable), spatial-scalable, and others. For example, as shown in Figure 6, a sequence can be downsampled to a low spatial resolution version. Both the low spatial resolution version and the original spatial resolution (high spatial resolution) version are coded. Generally, the low spatial resolution is coded first, and this is used as a reference for the high spatial resolution which is coded later.

[0203] To describe the layer information (number, dependencies, output), a VPS (Video Parameter Set) is defined as follows: [Table 1] JPEG2026097866000003.jpg244170 JPEG2026097866000004.jpg67170

[0204] The VPS RBSP shall be available to the decryption process before being referenced and shall be contained in at least one AU having a TemporalId equal to 0, or provided through external means.

[0205] All VPS NAL units within CVS that have a specific value for vps_video_parameter_set_id are assumed to have the same content.

[0206] The `vps_video_parameter_set_id` provides an identifier for the VPS for reference by other syntax elements. The value of `vps_video_parameter_set_id` must be greater than 0.

[0207] Adding 1 to vps_max_layers_minus1 specifies the maximum number of layers allowed within each CVS that references the VPS.

[0208] Adding 1 to vps_max_sublayers_minus1 specifies the maximum number of time sublayers that can exist in each CVS layer referencing the VPS. The value of vps_max_sublayers_minus1 must be in the range of 0 to 6.

[0209] A value of 1 for vps_all_layers_same_num_sublayers_flag specifies that all layers in each CVS referencing the VPS have the same number of time sublayers. A value of 0 for vps_all_layers_same_num_sublayers_flag specifies that each layer in each CVS referencing the VPS may or may not have the same number of time sublayers. If it does not exist, the value of vps_all_layers_same_num_sublayers_flag is assumed to be equal to 1.

[0210] A vps_all_independent_layers_flag equal to 1 specifies that all layers in CVS are coded independently without using inter-layer prediction. A vps_all_independent_layers_flag equal to 0 specifies that one or more layers in CVS may use inter-layer prediction. If it is not present, the value of vps_all_independent_layers_flag is assumed to be equal to 1.

[0211] vps_layer_id[i] specifies the nuh_layer_id value of the i-th layer. For any two non-negative integer values ​​of m and n, if m is less than n, then the value of vps_layer_id[m] is less than vps_layer_id[n].

[0212] A vps_independent_layer_flag[i] equal to 1 specifies that the layer with index i does not use inter-layer prediction. A vps_independent_layer_flag[i] equal to 0 specifies that the layer with index i may use inter-layer prediction, and that for j between 0 and i-1, the syntax element vps_direct_ref_layer_flag[i][j] exists in the VPS. If it does not exist, the value of vps_independent_layer_flag[i] is assumed to be equal to 1.

[0213] A vps_direct_ref_layer_flag[i][j] equal to 0 indicates that the layer with index j is not a direct reference layer of the layer with index i. A vps_direct_ref_layer_flag[i][j] equal to 1 indicates that the layer with index j is a direct reference layer of the layer with index i. For i and j in the range of 0 or greater and less than or equal to vps_max_layers_minus1, if vps_direct_ref_layer_flag[i][j] does not exist, it is assumed to be equal to 0. When vps_independent_layer_flag[i] is equal to 0, there must be at least one value of j in the range of 0 or greater and less than or equal to i-1 such that vps_direct_ref_layer_flag[i][j] is equal to 1.

[0214] The variables NumDirectRefLayers[i], DirectRefLayerIdx[i][d], NumRefLayers[i], RefLayerIdx[i][r], and LayerUsedAsRefLayerFlag[j] are derived as follows:

number

[0215] The variable GeneralLayerIdx[i], which specifies the layer index of the layer whose nuh_layer_id is equal to vps_layer_id[i], is derived as follows:

number

[0216] A value of each_layer_is_an_ols_flag equal to 1 specifies that each OLS contains only one layer, that each layer in CVS referencing the VPS is itself an OLS, and that the single contained layer is only the output layer. A value of each_layer_is_an_ols_flag equal to 0 means that an OLS may contain more than one layer. If vps_max_layers_minus1 is equal to 0, the value of each_layer_is_an_ols_flag is assumed to be equal to 1. Otherwise, if vps_all_independent_layers_flag is equal to 0, the value of each_layer_is_an_ols_flag is assumed to be equal to 0.

[0217] A value of ols_mode_idc equal to 0 indicates that the total number of OLS specified by the VPS is equal to vps_max_layers_minus1+1, the i-th OLS contains layers with layer indices between 0 and i (inclusive), and for each OLS, only the highest layer within the OLS is output.

[0218] A value of ols_mode_idc equal to 1 indicates that the total number of OLS specified by the VPS is equal to vps_max_layers_minus1+1, the i-th OLS contains layers with layer indices between 0 and i (inclusive), and for each OLS, all layers within the OLS are output.

[0219] A value of ols_mode_idc equal to 2 specifies that the total number of OLS specified by the VPS is explicitly signaled, the output layer for each OLS is explicitly signaled, and the other layers are layers that are direct or indirect reference layers of the output layer of the OLS.

[0220] The value of ols_mode_idc shall be in the range of 0 to 2. A value of ols_mode_idc of 3 is reserved for future use by ITU-T|ISO / IEC.

[0221] When vps_all_independent_layers_flag is equal to 1 and each_layer_is_an_ols_flag is equal to 0, the value of ols_mode_idc is estimated to be equal to 2.

[0222] Adding 1 to num_output_layer_sets_minus1 specifies the total number of OLS specified by the VPS when ols_mode_idc is equal to 2.

[0223] The variable TotalNumOlss, which specifies the total number of OLS designated by the VPS, is derived as follows.

number

[0224] A value of ols_output_layer_flag[i][j] equal to 1 indicates that, when ols_mode_idc is equal to 2, the layer with a nuh_layer_id equal to vps_layer_id[j] is the output layer of the i-th OLS. A value of ols_output_layer_flag[i][j] equal to 0 indicates that, when ols_mode_idc is equal to 2, the layer with a nuh_layer_id equal to vps_layer_id[j] is not the output layer of the i-th OLS.

[0225] The variables NumOutputLayersInOls[i], which specify the number of output layers in the i-th OLS, and OutputLayerIdInOls[i][j], which specify the nuh_layer_id value of the j-th output layer in the i-th OLS, are derived as follows:

number

[0226] For each OLS, there must be at least one output layer. In other words, for any value of i within the range of 0 to TotalNumOlss-1, the value of NumOutputLayersInOls[i] must be 1 or greater.

[0227] The variables NumLayersInOls[i], which specify the number of layers in the i-th OLS, and LayerIdInOls[i][j], which specify the nuh_layer_id value of the j-th layer in the i-th OLS, are derived as follows:

number

[0228] The variable OlsLayeIdx[i][j], which specifies the OLS layer index of the layer having a nuh_layer_id equal to LayerIdInOls[i][j], is derived as follows:

number

[0229] Assume that the lowest layer within each OLS is an independent layer. In other words, for each i within the range of 0 to TotalNumOlss - 1, the value of vps_independent_layer_flag[GeneralLayerIdx[LayerIdInOls[i][0]]] shall be equal to 1.

[0230] Assume that each layer is included in at least one OLS specified by the VPS. In other words, for each layer having a specific value nuhLayerId equal to one of vps_layer_id[k] for k within the range of 0 to vps_max_layers_minus1 such that the value of LayerIdInOls[i][j] is equal to nuhLayerId, there shall exist at least one pair of values of i and j, where i is within the range of 0 to TotalNumOlss - 1 and j is within the range of 0 to NumLayersInOls[i] - 1.

[0231] vps_num_ptls specifies the number of profile_tier_level() syntax structures within the VPS.

[0232] A value of pt_present_flag[i] equal to 1 specifies that profile, layer, and general constraint information exists in the i-th profile_tier_level() syntax structure within the VPS. A value of pt_present_flag[i] equal to 0 specifies that profile, layer, and general constraint information does not exist in the i-th profile_tier_level() syntax structure within the VPS. The value of pt_present_flag[0] is assumed to be equal to 1. When pt_present_flag[i] is equal to 0, the profile, layer, and general constraint information for the i-th profile_tier_level() syntax structure within the VPS is assumed to be the same as that for the (i - 1)-th profile_tier_level() syntax structure within the VPS.

[0233] ptl_max_temporal_id[i] specifies the TemporalId of the highest sublayer representation where the level information exists in the i-th profile_tier_level() syntax structure within the VPS. It is assumed that the value of ptl_max_temporal_id[i] is in the range from 0 to vps_max_sublayers_minus1. When vps_max_sublayers_minus1 is equal to 0, the value of ptl_max_temporal_id[i] is assumed to be 0. When vps_max_sublayers_minus1 is greater than 0 and vps_all_layers_same_num_sublayers_flag is equal to 1, the value of ptl_max_temporal_id[i] is assumed to be vps_max_sublayers_minus1.

[0234] vps_ptl_byte_alignment_zero_bit shall be equal to 0.

[0235] ols_ptl_idx[i] specifies the index to the list of profile_tier_level() syntax structures within the VPS for the profile_tier_level() syntax structure applied to the i-th OLS when numLayersInOls[i] is greater than 1. When it exists, it is assumed that the value of ols_ptl_idx[i] is in the range from 0 to vps_num_ptls - 1.

[0236] When NumLayersInOls[i] is equal to 1, the profile_tier_level() syntax structure applied to the i-th OLS exists in the SPS referenced by the layers within the i-th OLS.

[0237] vps_num_dpb_params specifies the number of dpb_parameters() syntax structures within the VPS. It is assumed that the value of vps_num_dpb_params is in the range from 0 to 16. When it does not exist, the value of vps_num_dpb_params is assumed to be 0.

[0238] A same_dpb_size_output_or_nonoutput_flag equal to 1 specifies that the layer_nonoutput_dpb_params_idx[i] syntax element does not exist on the VPS. A same_dpb_size_output_or_nonoutput_flag equal to 0 specifies that the layer_nonoutput_dpb_params_idx[i] syntax element may or may not exist on the VPS.

[0239] The `vps_sublayer_dpb_params_present_flag` is used to control the presence of the `max_dec_pic_buffering_minus1[]`, `max_num_reorder_pics[]`, and `max_latency_increase_plus1[]` syntax elements within the `dpb_parameters()` syntax structure in the VPS. When they are not present, `vps_sub_dpb_params_info_present_flag` is assumed to be equal to 0.

[0240] A dpb_size_only_flag[i] equal to 1 specifies that the max_num_reorder_pics[] and max_latency_increase_plus1[] syntax elements are not present in the i-th dpb_parameters() syntax structure within the VPS. A dpb_size_only_flag[i] equal to 0 specifies that the max_num_reorder_pics[] and max_latency_increase_plus1[] syntax elements may be present in the i-th dpb_parameters() syntax structure within the VPS.

[0241] dpb_max_temporal_id[i] specifies the TemporalId of the highest sublayer representation that the DPB parameter can have in the i-th dpb_parameters() syntax structure within the VPS. The value of dpb_max_temporal_id[i] is assumed to be in the range of 0 or greater and less than or equal to vps_max_sublayers_minus1. When vps_max_sublayers_minus1 is equal to 0, the value of dpb_max_temporal_id[i] is assumed to be equal to 0. When vps_max_sublayers_minus1 is greater than 0 and vps_all_layers_same_num_sublayers_flag is equal to 1, the value of dpb_max_temporal_id[i] is assumed to be equal to vps_max_sublayers_minus1.

[0242] `layer_output_dpb_params_idx[i]` specifies the index of the `dpb_parameters()` syntax structure to be applied to the i-th layer in the OLS, within a list of `dpb_parameters()` syntax structures in the VPS. If it exists, the value of `layer_output_dpb_params_idx[i]` is in the range of 0 or greater and less than or equal to `vps_num_dpb_params-1`.

[0243] If vps_independent_layer_flag[i] is equal to 1, then when it is an output layer, the dpb_parameters() syntax structure applied to the i-th layer is the dpb_parameters() syntax structure present in the SPS referenced by the layer.

[0244] Otherwise (when vps_independent_layer_flag[i] is equal to 0), the following applies: When -vps_num_dpb_params is equal to 1, the value of layer_output_dpb_params_idx[i] is presumed to be equal to 0. The bitstream compatibility requirement is that the value of -layer_output_dpb_params_idx[i] is such that dpb_size_only_flag[layer_output_dpb_params_idx[i]] is equal to 0.

[0245] `layer_nonoutput_dpb_params_idx[i]` specifies the index of the `dpb_parameters()` syntax structure applied to the i-th layer in the OLS, when it is a non-output layer, into a list of `dpb_parameters()` syntax structures in the VPS. If it exists, the value of `layer_nonoutput_dpb_params_idx[i]` is in the range of 0 or greater and less than or equal to `vps_num_dpb_params-1`.

[0246] If same_dpb_size_output_or_nonoutput_flag is equal to 1, then the following applies: -vps_independent_layer_flag[i] is equal to 1. When it is a non-output layer, the dpb_parameters() syntax structure applied to the i-th layer is the dpb_parameters() syntax structure that exists in the SPS referenced by the layer. - If not (vps_independent_layer_flag[i] is equal to 0), the value of layer_nonoutput_dpb_params_idx[i] is assumed to be equal to layer_output_dpb_params_idx[i].

[0247] Otherwise (when same_dpb_size_output_or_nonoutput_flag is equal to 0), if vps_num_dpb_params is equal to 1, the value of layer_output_dpb_params_idx[i] is presumed to be equal to 0.

[0248] A vps_general_hrd_params_present_flag equal to 1 indicates that the syntax structure general_hrd_parameters() and other HRD parameters exist in the VPS RBSP syntax structure. A vps_general_hrd_params_present_flag equal to 0 indicates that the syntax structure general_hrd_parameters() and other HRD parameters do not exist in the VPS RBSP syntax structure.

[0249] A vps_sublayer_cpb_params_present_flag equal to 1 specifies that the i-th ols_hrd_parameters() syntax structure in the VPS contains HRD parameters for sublayer representations having TemporalIds in the range of 0 or greater and hrd_max_tid[i] or less. A vps_sublayer_cpb_params_present_flag equal to 0 specifies that the i-th ols_hrd_parameters() syntax structure in the VPS contains HRD parameters for sublayer representations having only TemporalIds equal to hrd_max_tid[i]. When vps_max_sublayers_minus1 is equal to 0, the value of vps_sublayer_cpb_params_present_flag is assumed to be equal to 0.

[0250] When vps_sublayer_cpb_params_present_flag is equal to 0, the HRD parameters for a sublayer representation with a TemporalId in the range of 0 or greater and hrd_max_tid[i]-1 or less are assumed to be the same as those for a sublayer representation with a TemporalId equal to hrd_max_tid[i]. These include the HRD parameters starting from the fixed_pic_rate_general_flag[i] syntax element up to the sublayer_hrd_parameters(i) syntax structure immediately below the condition "if(general_vcl_hrd_params_present_flag)" in the ols_hrd_parameters syntax structure.

[0251] Adding 1 to num_ols_hrd_params_minus1 specifies the number of ols_hrd_parameters() syntax structures present in the general_hrd_parameters() syntax structure. The value of num_ols_hrd_params_minus1 is assumed to be in the range of 0 to 63. When TotalNumOlss is equal to 1, the value of num_ols_hrd_params_minus1 is assumed to be equal to 0.

[0252] hrd_max_tid[i] specifies the TemporalId of the highest sublayer representation in which the HRD parameter is included in the i-th ols_hrd_parameters() syntax structure. The value of hrd_max_tid[i] is assumed to be in the range of 0 or greater and less than or equal to vps_max_sublayers_minus1. When vps_max_sublayers_minus1 is equal to 0, the value of hrd_max_tid[i] is assumed to be equal to 0. When vps_max_sublayers_minus1 is greater than 0 and vps_all_layers_same_num_sublayers_flag is equal to 1, the value of hrd_max_tid[i] is assumed to be equal to vps_max_sublayers_minus1.

[0253] ols_hrd_idx[i] specifies the index of the ols_hrd_parameters() syntax structure to be applied to the i-th OLS. The value of ols_hrd_idx[i] shall be in the range from 0 to num_ols_hrd_params_minus1. When it does not exist, the value of ols_hrd_idx[i] is assumed to be equal to 0.

[0254] A vps_extension_flag equal to 0 specifies that the vps_extension_data_flag syntax element does not exist in the VPS RBSP syntax structure. A vps_extension_flag equal to 1 specifies that the vps_extension_data_flag syntax element exists in the VPS RBSP syntax structure.

[0255] vps_extension_data_flag may have any value. Its presence and value do not affect the decoder compliance to the profile specified in this version of this specification. Decoders compliant with this version of this specification shall ignore all vps_extension_data_flag syntax elements.

[0256] DPB Management and Referenced Picture Marking To manage these reference pictures during the decoding process, and for reference use in the decoding of subsequent pictures, the decoded pictures must be held in a decoding picture buffer (DPB). To indicate these pictures, their picture order count (POC) information must be signaled directly or indirectly in the slice header. Generally, there are two reference picture lists, namely list0 and list1. Reference picture indices must also be included to signal the pictures in the lists. In one-way prediction, reference pictures are fetched from one reference picture list, while in two-way prediction, reference pictures are fetched from two reference picture lists.

[0257] All reference pictures are stored in the DPB. All pictures in the DPB are marked as either "Used for Long-Term Reference," "Used for Short-Term Reference," or "Not Used for Reference," with only one of the three states. When a picture is marked as "Not Used for Reference," it is no longer used for reference. Furthermore, if it is not needed for output, it can be removed from the DPB. The state of a reference picture can be signaled in the slice header or derived from the slice header information.

[0258] A new reference picture management method called the RPL (reference picture list) method has been proposed. The RPL proposes an entire set or multiple sets of reference pictures for the current coding picture, and the reference pictures in the reference picture set are used to decode the current picture or future (later or subsequent) pictures. Therefore, the RPL reflects the picture information in the DPB, and even if a reference picture is not used as a reference for the current picture, it needs to be stored in the RPL if it is used as a reference for a subsequent picture.

[0259] After the picture is reconstructed, it is stored in the DPB and marked as "Use for short-term reference" by default. DPB management operations begin after parsing the RPL information in the slice header.

[0260] Reference picture list configuration Reference picture information can be signaled via the slice header. Furthermore, the Sequence Parameter Set (SPS) may contain several RPL candidates; in this case, the slice header may include an RPL index to retrieve the necessary RPL information without signaling the entire RPL syntax structure. Alternatively, the entire RPL syntax structure can be signaled via the slice header.

[0261] Introduction to the RPL Method To save on RPL signaling costs, several RPL candidates may exist within the SPS. A picture can use the RPL index (ref_pic_list_idx[i]) to retrieve its RPL information from the SPS. RPL candidates are signaled as follows: [Table 2]

[0262] The meaning is as follows:

[0263] A flag equal to 1, rpl1_same_as_rpl0_flag, indicates that the syntax structures num_ref_pic_lists_in_sps[1] and ref_pic_list_struct(1, rplsIdx) do not exist, and the following applies: -The value of num_ref_pic_lists_in_sps[1] is presumed to be equal to the value of num_ref_pic_lists_in_sps[0]. The value of each syntax element in -ref_pic_list_struct(1,rplsIdx) is assumed to be equal to the value of the corresponding syntax element in ref_pic_list_struct(0,rplsIdx) for rplsIdx in the range of 0 to num_ref_pic_lists_in_sps[0]-1.

[0264] num_ref_pic_lists_in_sps[i] specifies the number of ref_pic_list_struct(listIdx,rplsIdx) syntax structures in the SPS that have a listIdx equal to i. The value of num_ref_pic_lists_in_sps[i] must be in the range of 0 to 64.

[0265] In addition to obtaining RPL information based on the RPL index from SPS, RPL information can also be signaled in the slice header. [Table 3]

[0266] A ref_pic_list_sps_flag[i] equal to 1 specifies that the reference picture list i of the current slice is derived based on one of the ref_pic_list_struct(listIdx,rplsIdx) syntax structures having a listIdx equal to i in the SPS. A ref_pic_list_sps_flag[i] equal to 0 specifies that the reference picture list i of the current slice is derived based on a ref_pic_list_struct(listIdx,rplsIdx) syntax structure having a listIdx equal to i, which is directly included in the slice header of the current picture.

[0267] If ref_pic_list_sps_flag[i] does not exist, the following applies: -If num_ref_pic_lists_in_sps[i] is equal to 0, the value of ref_pic_list_sps_flag[i] is presumed to be equal to 0. -If not (num_ref_pic_lists_in_sps[i] is greater than 0) and rpl1_idx_present_flag is equal to 0, then the value of ref_pic_list_sps_flag[1] is presumed to be equal to ref_pic_list_sps_flag[0]. -Otherwise, the value of ref_pic_list_sps_flag[i] is presumed to be equal to pps_ref_pic_list_sps_idc[i]-1.

[0268] ref_pic_list_idx[i] specifies an index to a list of ref_pic_list_struct(listIdx, rplsIdx) syntax structures containing i that have a listIdx equal to i, which are currently used to derive the reference picture list i of the picture. The syntax element ref_pic_list_idx[i] is represented by Ceil(Log2(num_ref_pic_lists_in_sps[i])) bits. If it does not exist, the value of ref_pic_list_idx[i] is assumed to be equal to 0. The value of ref_pic_list_idx[i] is in the range of 0 or greater and num_ref_pic_lists_in_sps[i]-1 or less. When ref_pic_list_sps_flag[i] is equal to 1 and num_ref_pic_lists_in_sps[i] is equal to 0, the value of ref_pic_list_idx[i] is presumed to be equal to 0. When ref_pic_list_sps_flag[i] is equal to 1 and rpl1_idx_present_flag is equal to 0, the value of ref_pic_list_idx[1] is presumed to be equal to ref_pic_list_idx[0].

[0269] The variable RplsIdx[i] is derived as follows:

number

[0270] slice_poc_lsb_lt[i][j] specifies the modulo MaxPicOrderCntLsb value of the picture order count of the jth LTRP entry in the i-th reference picture list. The length of the slice_poc_lsb_lt[i][j] syntax element is log2_max_pic_order_cnt_lsb_minus4+4 bits.

[0271] The variable PocLsbLt[i][j] is derived as follows:

number

[0272] A delta_poc_msb_present_flag[i][j] equal to 1 indicates that delta_poc_msb_cycle_lt[i][j] exists. A delta_poc_msb_present_flag[i][j] equal to 0 indicates that delta_poc_msb_cycle_lt[i][j] does not exist.

[0273] prevTid0Pic is the previous picture in the decoding order that has the same nuh_layer_id as the current picture, a TemporalId equal to 0, and is not a RASL or RADL picture. setOfPrevPocVals is a set consisting of the following: -prevTid0Pic's PicOrderCntVal, -The PicOrderCntVal of each picture that is referenced by an entry in RefPicList[0] or RefPicList[1] of prevTid0Pic and currently has the same nuh_layer_id as the picture, - The PicOrderCntVal for each picture that follows prevTid0Pic in the decoding order, has the same nuh_layer_id as the current picture, and precedes the current picture in the decoding order.

[0274] If there are more than one value equal to the value modulo MaxPicOrderCntLsb in setOfPrevPocVals, then the value of delta_poc_msb_present_flag[i][j] is equal to 1.

[0275] delta_poc_msb_cycle_lt[i][j] specifies the value of the variable FullPocLt[i][j] as follows:

number

[0276] The value of delta_poc_msb_cycle_lt[i][j] is between 0 and 2. (32-log2_max_pic_order_cnt_lsb_minus4-4) The following range is assumed. If it does not exist, the value of delta_poc_msb_cycle_lt[i][j] is assumed to be equal to 0.

[0277] The syntax structure of RPL is as follows: [Table 4]

[0278] num_ref_entries[listIdx][rplsIdx] specifies the number of entries in the ref_pic_list_struct(listIdx, rplsIdx) syntax structure. The value of num_ref_entries[listIdx][rplsIdx] must be in the range of 0 or greater and sps_max_dec_pic_buffering_minus1+14 or less.

[0279] A value of 0 for ltrp_in_slice_header_flag[listIdx][rplsIdx] indicates that the POC LSB for an LTRP entry in the ref_pic_list_struct(listIdx,rplsIdx) syntax structure exists in the ref_pic_list_struct(listIdx,rplsIdx) syntax structure. A value of 1 for ltrp_in_slice_header_flag[listIdx][rplsIdx] indicates that the POC LSB for an LTRP entry in the ref_pic_list_struct(listIdx,rplsIdx) syntax structure does not exist in the ref_pic_list_struct(listIdx,rplsIdx) syntax structure.

[0280] An inter_layer_ref_pic_flag[listIdx][rplsIdx][i] equal to 1 specifies that the i-th entry in the ref_pic_list_struct(listIdx,rplsIdx) syntax structure is an ILRP entry. An inter_layer_ref_pic_flag[listIdx][rplsIdx][i] equal to 0 specifies that the i-th entry in the ref_pic_list_struct(listIdx,rplsIdx) syntax structure is not an ILRP entry. If none exists, the value of inter_layer_ref_pic_flag[listIdx][rplsIdx][i] is assumed to be equal to 0.

[0281] A value of 1 for st_ref_pic_flag[listIdx][rplsIdx][i] indicates that the i-th entry in the ref_pic_list_struct(listIdx,rplsIdx) syntax structure is a STRP entry. A value of 0 for st_ref_pic_flag[listIdx][rplsIdx][i] indicates that the i-th entry in the ref_pic_list_struct(listIdx,rplsIdx) syntax structure is an LTRP entry. When inter_layer_ref_pic_flag[listIdx][rplsIdx][i] is equal to 0 and st_ref_pic_flag[listIdx][rplsIdx][i] does not exist, the value of st_ref_pic_flag[listIdx][rplsIdx][i] is assumed to be equal to 1.

[0282] The variable NumLtrpEntries[listIdx][rplsIdx] is derived as follows:

number

[0283] abs_delta_poc_st[listIdx][rplsIdx][i] specifies the value of the variable AbsDeltaPocSt[listIdx][rplsIdx][i] as follows:

number

[0284] The value of abs_delta_poc_st[listIdx][rplsIdx][i] is between 0 and 2. 15 The range must be -1 or less.

[0285] A value of 1 for strp_entry_entry_sign_flag[listIdx][rplsIdx][i] indicates that the i-th entry in the syntax structure ref_pic_list_struct(listIdx,rplsIdx) has a value of 0 or greater. A value of 0 for strp_entry_sign_flag[listIdx][rplsIdx][i] indicates that the i-th entry in the syntax structure ref_pic_list_struct(listIdx,rplsIdx) has a value of less than 0. If none exists, the value of strp_entry_sign_flag[listIdx][rplsIdx][i] is assumed to be equal to 1.

[0286] The list DeltaPocValSt[listIdx][rplsIdx] is derived as follows:

number

[0287] rpls_poc_lsb_lt[listIdx][rplsIdx][i] specifies the modulo MaxPicOrderCntLsb value of the picture order count of the picture referenced by the i-th entry in the ref_pic_list_struct(listIdx,rplsIdx) syntax structure. The length of the rpls_poc_lsb_lt[listIdx][rplsIdx][i] syntax element is log2_max_pic_order_cnt_lsb_minus4+4 bits.

[0288] Some general descriptions of RPL structures An RPL structure exists for each list. First, num_ref_entries[listIdx][rplsIdx] is signaled to indicate the number of reference pictures in the list. ltrp_in_slice_header_flag[listIdx][rplsIdx] is used to indicate whether LSB (Least Significant Byte) information is signaled in the slice header. If the current reference picture is not an interlayer reference picture, st_ref_pic_flag[listIdx][rplsIdx][i] indicates whether it is a long-term reference picture. If it is a short-term reference picture, POC information (abs_delta_poc_st and strp_entry_sign_flag) is signaled. If ltrp_in_slice_header_flag[listIdx][rplsIdx] is zero, rpls_poc_lsb_lt[listIdx][rplsIdx][j++] is used to derive the LSB information of the current reference picture. The MSB (Most Significant Bit) can be derived directly or based on the information in the slice header (delta_poc_msb_present_flag[i][j] and delta_poc_msb_cycle_lt[i][j]).

[0289] Decryption process for constructing the reference picture list This process is invoked for each slice of non-IDR picture at the start of the decoding process.

[0290] Reference pictures are handled through a reference index. The reference index is an index to the reference picture list. When decoding an I slice, the reference picture list is not used in decoding the slice data. When decoding a P slice, only reference picture list 0 (i.e., RefPicList[0]) is used in decoding the slice data. When decoding a B slice, both reference picture list 0 and reference picture list 1 (i.e., RefPicList[1]) are used in decoding the slice data.

[0291] At the start of the decoding process for each slice of a non-IDR picture, the reference picture lists RefPicList[0] and RefPicList[1] are derived. The reference picture lists are used in marking the reference pictures or in decoding the slice data, as specified in Section 8.3.3. Note 1 - For I slices of non-IDR pictures that are not the first slice of a picture, RefPicList[0] and RefPicList[1] may be derived for the purpose of bitstream conformance checking, but this derivation is not necessary for decoding the current picture or pictures that follow the current picture in decoding order. For P slices that are not the first slice of a picture, RefPicList[1] may be derived for the purpose of bitstream conformance checking, but this derivation is not necessary for decoding the current picture or pictures that follow the current picture in decoding order.

[0292] The reference picture lists RefPicList[0] and RefPicList[1], the reference picture scaling ratios RefPicScale[i][j][0] and RefPicScale[i][j][1], and the reference picture scaling flags RefPicIsScaled[0] and RefPicIsScaled[1] are configured as follows:

number

[0293] For each i equal to 0 or 1, the first NumRefIdxActive[i] entry in RefPicList[i] is called the active entry in RefPicList[i], and the other entries in RefPicList[i] are called the inactive entries in RefPicList[i]. Note 2 - A particular picture can be referenced by entries in both RefPicList[0] and RefPicList[1]. A particular picture can also be referenced by more than one entry in RefPicList[0] or more than one entry in RefPicList[1]. Note 3 - Active entries in RefPicList[0] and RefPicList[1] refer collectively to all reference pictures that can be used for interpretation of the current picture and one or more pictures that follow the current picture in decoding order. Inactive entries in RefPicList[0] and RefPicList[1] refer collectively to all reference pictures that are not used for interpretation of the current picture but can be used for interpretation of one or more pictures that follow the current picture in decoding order. Note 4 - Since the corresponding picture does not exist in the DPB, RefPicList[0] or RefPicList[1] may contain one or more entries equivalent to "no reference picture". Each inactive entry in RefPicList[0] or RefPicList[0] that is equivalent to "no reference picture" should be ignored. For each active entry in RefPicList[0] or RefPicList[1] that is equivalent to "no reference picture", an unintended picture loss should be estimated.

[0294] The following constraints apply to the bitstream compatibility requirements. For each i equal to -0 or 1, num_ref_entries[i][RplsIdx[i]] is not less than NumRefIdxActive[i]. -The pictures referenced by each active entry in RefPicList[0] or RefPicList[1] are assumed to exist in the DPB and have a TemporalId less than or equal to the current picture's TemporalId. -A picture referenced by each entry in RefPicList[0] or RefPicList[1] is currently not a picture and has a non_reference_picture_flag equal to 0. -STRP entries in RefPicList[0] or RefPicList[1] of a picture slice and LTRP entries in RefPicList[0] or RefPicList[1] of the same slice or different slices of the same picture shall not refer to the same picture. - The difference between the current picture's PicOrderCntVal and the picture's PicOrderCntVal referenced by the entry is 2. 24 Assume that there are no LTRP entries in RefPicList[0] or RefPicList[1] that meet the above criteria. -setOfRefPics is defined as a set of unique pictures referenced by all entries in RefPicList[0] that have the same nuh_layer_id as the current picture, and all entries in RefPicList[1] that have the same nuh_layer_id as the current picture. The number of pictures in setOfRefPics is assumed to be less than or equal to MaxDecPicBuffMinus1, and setOfRefPics is assumed to be the same for all slices of the picture. -When the current picture is an STSA picture, it is assumed that there are no active entries in RefPicList[0] or RefPicList[1] that have a TemporalId equal to the TemporalId of the current picture. -When the current picture is a picture that follows an STSA picture that has a TemporalId equal to the current picture's TemporalId in the decoding order, it is assumed that there are no pictures with a TemporalId equal to the current picture's TemporalId included as active entries in RefPicList[0] or RefPicList[1] that precede the STSA picture in the decoding order. -When the current picture is a CRA picture, it is assumed that there are no pictures referenced by entries in RefPicList[0] or RefPicList[1] that precede any preceding IRAP picture (if any) in the decoding order, either in the output order or the decoding order. -When the current picture is a trailing picture, there are no pictures referenced by active entries in RefPicList[0] or RefPicList[1] generated by the decryption process to generate an unavailable reference picture for the IRAP picture associated with the current picture. -When the current picture is a trailing picture following one or more leading pictures associated with the same IRAP picture, both in the decoding order and the output order, it is assumed that there are no pictures referenced by entries in RefPicList[0] or RefPicList[1] generated by the decoding process to generate an unavailable reference picture for the IRAP picture associated with the current picture. -If the current picture is a recovery point picture or a picture that follows the recovery point picture in output order, there are no entries in RefPicList[0] or RefPicList[1] that contain pictures generated by the decoding process to generate an unavailable reference picture for the GDR picture of the recovery point picture. -When the current picture is a trailing picture, it is assumed that there are no pictures referenced by active entries in RefPicList[0] or RefPicList[1] that precede the related IRAP picture in output order or decoding order. -If the current picture is a trailing picture that follows one or more reading pictures associated with the same IRAP picture, both in the decoding order and the output order, then there are no pictures referenced by entries in RefPicList[0] or RefPicList[1] that precede the associated IRAP picture in the output order or the decoding order. -Assuming that the current picture is a RADL picture, there are no active entries in RefPicList[0] or RefPicList[1] that are any of the following: RASL Pictures • Pictures generated by the decryption process to create unavailable reference pictures • Pictures preceding related IRAP pictures in the decryption order -The pictures referenced by each ILRP entry in RefPicList[0] or RefPicList[1] of the current picture slice are assumed to be in the same AU as the current picture. -The pictures referenced by each ILRP entry in RefPicList[0] or RefPicList[1] of the current picture slice are assumed to exist in the DPB and have a nuh_layer_id smaller than the current picture's nuh_layer_id. - Each ILRP entry in RefPicList[0] or RefPicList[1] of the slice is assumed to be an active entry.

[0295] After the RPL is configured, the marking process is as follows:

[0296] Decryption process for reference picture marking This process is called once per picture, after the decoding process for decoding the slice header and constructing the reference picture list for the slice, as specified in Section 8.3.2, but before decoding the slice data. This process may result in one or more reference pictures in the DPB being marked as "not used for reference" or "used for long-term reference".

[0297] A decrypted picture in the DPB can be marked as "not used for reference," "used for short-term reference," or "used for long-term reference," but at any given point in time during the decryption process, it is only one of these three. Assigning one of these markings to a picture implicitly removes the others when applicable. When a picture is referred to as being marked as "used for reference," this also refers to a picture that is marked as either "used for short-term reference" or "used for long-term reference" (but not both).

[0298] STRP and ILRP are identified by their nuh_layer_id and PicOrderCntVal values. LTRP are identified by the Log2(MaxLtPicOrderCntLsb)LSB of their nuh_layer_id and PicOrderCntVal values.

[0299] If the current picture is a CLVSS picture, all current referenced pictures in the DPB (if any) that have the same nuh_layer_id as the current picture will be marked as "unused for reference".

[0300] Otherwise, the following applies: -For each LTRP entry in RefPicList[0] or RefPicList[1], if the referenced picture is a STRP with the same nuh_layer_id as the current picture, the picture is marked as “Use for long-term reference”. -Each referenced picture that has the same nuh_layer_id as the current picture in the DPB and is not referenced by any entry in RefPicList[0] or RefPicList[1] is marked as "not used for reference". -For each ILRP entry in RefPicList[0] or RefPicList[1], the referenced picture is marked as “Use for long-term reference”.

[0301] It is permissible to have asynchronous IRAP pictures between layers. To support this design, the following POC design mixes IRAP and non-IRAP pictures within the AU.

[0302] In the independent layer, POC MSB cycle signaling is used. The SPS has a flag that controls whether the picture header has ph_poc_msb_cycle_present_flag and length within the SPS. When ph_poc_msb_cycle_present_flag is equal to 1, u(v) coded POC MSB cycles are signaled in the picture header. When POC MSB cycles exist, the picture's POC MSB is set to poc_msb_cycle*MaxPicOrderCntLsb.

[0303] In a dependent layer, if a picture picA exists in the same AU as the current layer's reference layer, the POC is derived as being equal to the POC of piA, and the POC LSB values ​​must be aligned across layers. Otherwise, the current POC derivation process applies. [Table 5]

[0304] bit_depth_minus8 specifies the bit depth BitDepth of the samples in the luma and chroma arrays, and the value QpBdOffset of the luma and chroma quantization parameter range offset, as follows:

number

[0305] When sps_decoding_parameter_set_id is greater than 0, it specifies the value of dps_decoding_parameter_set_id for the DPS referenced by the SPS. When sps_decoding_parameter_set_id is equal to 0, the SPS does not reference the DPS, and when decoding each CLVS by referencing the SPS, the DPS is not referenced. The value of sps_decoding_parameter_set_id is assumed to be the same for all SPS referenced by coded pictures in the bitstream.

[0306] When sps_video_parameter_set_id is greater than 0, it specifies the value of vps_video_parameter_set_id for the VPS referenced by SPS.

[0307] When sps_video_parameter_set_id is equal to 0, the following applies: -SPS does not refer to VPS. -When decrypting each CLVS by referencing the SPS, the VPS is not referenced. The value of -vps_max_layers_minus1 is estimated to be equal to 0. - The CVS shall contain only one layer (i.e., all VCL NAL units within the CVS shall have the same value as nuh_layer_id). -The value of GeneralLayerIdx[nuh_layer_id] is presumed to be equal to 0. The value of -vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is estimated to be equal to 1.

[0308] When vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is equal to 1, an SPS referenced by a CLVS having a specific nuh_layer_id value nuhLayerId shall have a nuh_layer_id equal to nuhLayerId.

[0309] chroma_format_idc specifies chromasampling for lumasampling, as specified in Section 6.2.

[0310] A separate_colour_plane_flag equal to 1 specifies that the three color components of the 4:4:4 chroma format are coded separately. A separate_colour_plane_flag equal to 0 specifies that the color components are not coded separately. When separate_colour_plane_flag is not present, it is assumed to be equal to 0. When separate_colour_plane_flag is equal to 1, the coded picture consists of three separate components, each of which consists of a coded sample of one color plane (Y, Cb, or Cr) using the monochrome coding syntax. In this case, each color plane is associated with a specific colour_plane_id value. Note 1 - There is no dependency between the decoding processes for color planes with different colour_plane_id values. For example, the decoding process for a monochrome picture with one colour_plane_id value does not use data from monochrome pictures with different colour_plane_id values ​​for interpretation.

[0311] Depending on the value of `separate_colour_plane_flag`, the value of the variable `ChromaArrayType` is assigned as follows: If -separate_colour_plane_flag is equal to 0, ChromaArrayType is set to equal to chroma_format_idc. - Otherwise (if separate_colour_plane_flag is equal to 1), ChromaArrayType is set to equal to 0.

[0312] The meanings of chroma_format_idc and separate_colour_plane_flag are used to indicate the chroma format. [Table 6]

[0313] A sps_poc_msb_flag equal to 1 indicates that the ph_poc_msb_cycle_present_flag syntax element exists in a PH that references an SPS. A sps_poc_msb_flag equal to 0 indicates that the ph_poc_msb_cycle_present_flag syntax element does not exist in a PH that references an SPS.

[0314] Adding 1 to poc_msb_len_minus1 specifies the length of the poc_msb_val syntax element in bits when it exists in a PH that references SPS. The value of poc_msb_len_minus1 must be in the range of 0 or greater and 32-log2_max_pic_order_cnt_lsb_minus4-5 or less. [Table 7]

[0315] A ph_poc_msb_present_flag equal to 1 indicates that the syntax element poc_msb_val exists in the PH. A ph_poc_msb_present_flag equal to 0 indicates that the syntax element poc_msb_val does not exist in the PH. The value of ph_poc_msb_present_flag is equal to 0 when vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is equal to 0 and the reference layer of the current layer contains a picture within the current AU.

[0316] poc_msb_val specifies the POC MSB value of the current picture. The length of the syntax element poc_msb_val is poc_msb_len_minus1+1 bits.

[0317] The following is the derivation of the picture order count (POC) for the current picture.

[0318] Decoding process for picture order count The output of this process is PicOrderCntVal, which is the picture order count of the current picture.

[0319] Each coded picture is associated with a picture order count variable, which is represented as PicOrderCntVal.

[0320] If vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is equal to 0 and the current layer's reference layer contains picture picA within the current AU, then PicOrderCntVal is derived to be equal to the PicOrderCntVal of picA, and the value of slice_pic_order_cnt_lsb is the same for all VCL NAL units in the current AU. Otherwise, the PicOrderCntVal of the current picture is derived as specified below.

[0321] When ph_poc_msb_present_flag is equal to 0 and the current picture is not a CLVSS picture, the variables prevPicOrderCntLsb and prevPicOrderCntMsb are derived as follows: -prevTid0Pic is the previous picture in the decoding order that has a nuh_layer_id equal to the current picture's nuh_layer_id and a TemporalId equal to 0, and is not a RASL or RADL picture. - The variable prevPicOrderCntLsb is set to be equal to slice_pic_order_cnt_lsb of prevTid0Pic. - The variable prevPicOrderCntMsb is set to be equal to the PicOrderCntMsb of prevTid0Pic.

[0322] The current picture variable PicOrderCntMsb is derived as follows: -If ph_poc_msb_present_flag is equal to 1, PicOrderCntMsb is set to equal to poc_msb_val * MaxPicOrderCntLsb. - If not (ph_poc_msb_present_flag is equal to 0), and the picture is currently a CLVSS picture, then PicOrderCntMsb is set to equal to 0. -Otherwise, PicOrderCntMsb is derived as follows:

number

[0323] PicOrderCntVal is derived as follows:

number

number

number

[0324] Constraints of sps_poc_msb_flag The flag sps_poc_msb_flag is used to control whether the flag ph_poc_msb_cycle_present_flag is presented in the picture header. On the other hand, mixed IRAP and non-IRAP pictures within an AU only need to be enabled in multi-layer scenarios. Therefore, there is no need to present ph_poc_msb_cycle_present_flag in single-layer coding scenarios. Thus, the value of sps_poc_msb_flag can be constrained to be 0 in single-layer coding scenarios.

[0325] 1.2 Constraints on chroma_format_idc, separate_colour_plane_flag, and bit_depth_minus8 The current motion compensation process can be used for inter-layer prediction, but it cannot be used when different layers have different formats (chroma_format_idc, separate_colour_plane_flag, bit_depth_minus8, etc.).

[0326] It is proposed to constrain the value of sps_poc_msb_flag to be equal to 0 in multilayer coding scenarios.

[0327] It is proposed to restrict cross-layer prediction to only be usable when the current picture in the current layer and the reference picture in the reference layer have the same format.

[0328] The flag sps_poc_msb_flag is used to control whether the flag ph_poc_msb_cycle_present_flag is presented in the picture header. On the other hand, mixed IRAP and non-IRAP pictures within an AU only need to be enabled in multi-layer scenarios. Therefore, there is no need to present ph_poc_msb_cycle_present_flag in single-layer coding scenarios. Thus, the value of sps_poc_msb_flag can be constrained to be 0 in single-layer coding scenarios.

[0329] First Embodiment [Constraints on sps_poc_msb_flag] The meaning of sps_poc_msb_flag can be changed as follows: A sps_poc_msb_flag equal to 1 indicates that the ph_poc_msb_cycle_present_flag syntax element exists in a PH that references an SPS. A sps_poc_msb_flag equal to 0 indicates that the ph_poc_msb_cycle_present_flag syntax element does not exist in a PH that references an SPS. When vps_max_layers_minus1 is equal to 0, the value of sps_poc_msb_flag is considered to be equal to 0.

[0330] Second Embodiment [Format Constraints] The following constraints need to be added to the specifications. A vps_direct_ref_layer_flag[i][j] equal to 0 indicates that the layer with index j is not a direct reference layer of the layer with index i. A vps_direct_ref_layer_flag[i][j] equal to 1 indicates that the layer with index j is a direct reference layer of the layer with index i. For i and j in the range of 0 or greater and less than or equal to vps_max_layers_minus1, if vps_direct_ref_layer_flag[i][j] does not exist, it is assumed to be equal to 0. When vps_independent_layer_flag[i] is equal to 0, there must be at least one value of j in the range of 0 or greater and less than or equal to i-1 such that vps_direct_ref_layer_flag[i][j] is equal to 1. The variables NumDirectRefLayers[i], DirectRefLayerIdx[i][d], NumRefLayers[i], RefLayerIdx[i][r], and LayerUsedAsRefLayerFlag[j] are derived as follows:

number

number

[0331] Constraint Option A: If the current layer is a dependent layer, the video in the current layer shall have the same chroma_format_idc as the video in the reference layer. Furthermore, it can be said that cross-layer prediction is only usable when the video in the current layer has the same chroma_format_idc as the video in the reference layer.

[0332] Constraint Option B: If the current layer is a dependent layer, the video in the current layer shall have the same separate_colour_plane_flag as the video in the reference layer. Furthermore, it can be said that cross-layer prediction can only be used when the video in the current layer has the same separate_colour_plane_flag as the video in the reference layer.

[0333] Constraint option C: If the current layer is a dependent layer, the video in the current layer shall have the same bit_depth_minus8 as the video in the reference layer. Furthermore, it can be said that cross-layer prediction can only be used when the video in the current layer has the same bit_depth_minus8 as the video in the reference layer.

[0334] Options A, B, and C can be combined.

[0335] For example, option A+B: If the current layer is a dependent layer, the video in the current layer shall have the same chroma_format_idc and separate_colour_plane_flag as the video in the reference layer. Furthermore, it can be said that cross-layer prediction is only usable when the video in the current layer has the same chroma_format_idc and separate_colour_plane_flag as the video in the reference layer.

[0336] For example, option A+B+C: If the current layer is a dependent layer, the video in the current layer shall have the same chroma_format_idc, separate_colour_plane_flag, and bit_depth_minus8 as the video in the reference layer. Furthermore, it can be said that cross-layer prediction is only usable when the video in the current layer has the same chroma_format_idc, separate_colour_plane_flag, and bit_depth_minus8 as the video in the reference layer.

[0337] Third Embodiment [Format Constraints] Constraints can also be added in other ways. 8. Decryption Process 8.1 General Decryption Process 8.1.1 General The input to this process is a bitstream (BitstreamToDecode). The output of this process is a list of decoded pictures. The decoding process is specified to produce numerically identical cropped decoded output pictures when all decoders conforming to a given profile and level invoke the decoding process associated with that profile for bitstreams conforming to that profile and level. Any decoding process that produces the same cropped decoded output picture as those produced by the processes described herein (and has the specified correct output order or output timing) conforms to the decoding process requirements of this specification. For each IRAP AU in the bitstream, the following applies: -The variable NoIncorrectPicOutputFlag is set to 1 if AU is the first AU in the bitstream in decoding order, each picture is an IDR picture, or each picture is the first picture in the layer following the EOS NAL unit in decoding order. - If any external means not specified in this specification is available to set the variable HandleCraAsCvsStartFlag to a value for the AU, HandleCraAsCvsStartFlag will be set to the value provided by the external means, and NoIncorrectPicOutputFlag will be set to HandleCraAsCvsStartFlag. - Otherwise, HandleCraAsCvsStartFlag and NoIncorrectPicOutputFlag will both be set to 0. For each GDR AU in the bitstream, the following applies: -If AU is the first AU in the bitstream in decoding order, or if each picture is the first picture in the layer following the EOS NAL unit in decoding order, the variable NoIncorrectPicOutputFlag is set to equal 1. - If any external means not specified in this specification is available to set the variable HandleGdrAsCvsStartFlag to a value for AU, HandleGdrAsCvsStartFlag will be set to the value provided by the external means, and NoIncorrectPicOutputFlag will be set to HandleGdrAsCvsStartFlag. - Otherwise, HandleGdrAsCvsStartFlag and NoIncorrectPicOutputFlag will both be set to 0. Note - For both IRAP pictures and GDR pictures, the above operation is necessary to identify the CVS within the bitstream. The variable TargetOlsIdx, which identifies the OLS index of the target OLS to be decoded, and the variable Htid, which identifies the highest time sublayer to be decoded, are set by some external means not specified in this specification. The bitstream BitstreamToDecode does not include layers other than those included in the target OLS and does not include NAL units with a TemporalId greater than Htid. Section 8.1.2 is called repeatedly for each coded picture in BitstreamToDecode, in the order of decoding.

[0338] Option A: When BitstreamToDecode contains more than one layer, the following properties of each layer are assumed to be the same: -chroma_format_idc -separate_colour_plane_flag

[0339] Option B: When BitstreamToDecode contains more than one layer, the following properties of each layer are assumed to be the same: -bit_depth_minus8

[0340] Option C = Option A + Option B When BitstreamToDecode contains more than one layer, the following properties of each layer are assumed to be the same: -chroma_format_idc -separate_colour_plane_flag -bit_depth_minus8

[0341] (1) When a single-layer coding scenario is used to clean up the design for POC derivation, the constraint is that the value of sps_poc_msb_flag is equal to 0. (2) Constrain the format of the current layer and reference layer in inter-layer prediction to simplify the design.

[0342] Figure 7 is a schematic flowchart showing a method for decoding a coded video bitstream according to an embodiment of the present application, which may be performed by an apparatus for decoding a coded video bitstream, and as shown in Figure 7, the method for decoding a coded video bitstream may include the following steps 701 to 703.

[0343] S701 By parsing the coded video bitstream, a reference layer syntax element is obtained, the value of which specifies whether the layer with index k is a direct reference layer of the layer with index i, and both i and k are integers and greater than or equal to 0.

[0344] Specifically, a layer is a sequence of pictures, and the pictures within a sequence share the same layer identifier or layer index.

[0345] Specifically, a device for decoding a coded video bitstream (e.g., the decoder shown in Figure 3) is configured to parse the bitstream 21 (or generally coded picture data 21), perform entropy decoding to the coded picture data 21, and obtain, for example, all or any of the following: quantization coefficients 309 and / or decoding coding parameters (not shown in Figure 3), for example, inter-prediction parameters (e.g., reference picture index and motion vector), intra-prediction parameters (e.g., intra-prediction mode or index), transformation parameters, quantization parameters, loop filter parameters, reference layer syntax elements, chroma format-related syntax elements, bit depth-related syntax elements, and / or other syntax elements. The entropy decoding unit 304 may be configured to apply a decoding algorithm or scheme corresponding to an coding scheme such as those described with respect to the entropy coding unit 270 of the encoder 20. The entropy decoding unit 304 may be further configured to provide inter-prediction parameters, intra-prediction parameters, and / or other syntax elements to the mode application unit 360, and to provide other parameters to other units of the decoder 30. The video decoder 30 may receive syntax elements at the video slice level and / or video block level. In addition to or as an alternative to slices and their respective syntax elements, tile groups and / or tiles and their respective syntax elements may be received and / or used.

[0346] In this embodiment, the reference layer syntax element is a video parameter set (VPS) level syntax element, where the VPS is applied to the layer having index j and the layer having index i.

[0347] In this embodiment, the reference layer syntax element may also be the syntax element vps_direct_ref_layer_flag[i][j] in the VPS table described above.

[0348] A vps_direct_ref_layer_flag[i][j] equal to 0 indicates that the layer with index j is not a direct reference layer of the layer with index i. A vps_direct_ref_layer_flag[i][j] equal to 1 indicates that the layer with index j is a direct reference layer of the layer with index i. For i and j in the range of 0 or greater and less than or equal to vps_max_layers_minus1, if vps_direct_ref_layer_flag[i][j] does not exist, it is assumed to be equal to 0. When vps_independent_layer_flag[i] is equal to 0, there must be at least one value of j in the range of 0 or greater and less than or equal to i-1 such that vps_direct_ref_layer_flag[i][j] is equal to 1.

[0349] The variables NumDirectRefLayers[i], DirectRefLayerIdx[i][d], NumRefLayers[i], RefLayerIdx[i][r], and LayerUsedAsRefLayerFlag[j] are derived as follows:

number

[0350] Specifically, a vps_direct_ref_layer_flag[i][j] equal to 1 specifies that the layer with index j is a direct reference layer of the layer with index i.

[0351] S702 Based on the value of the reference layer syntax element, it is determined whether the layer having index j is a reference layer of the layer having index i. If the layer having index j is a reference layer of the layer having index k, then j is an integer and greater than or equal to 0.

[0352] In this embodiment, if the value of the reference layer syntax element specifies that the layer having index k is a direct reference layer of the layer having index i, then the layer having index j is a reference layer of the layer having index i.

[0353] Specifically, with respect to reference layers, there are two types of scenarios: one is that the layer with index A is a direct reference layer of the layer with index B, and the other is that the layer with index A is an indirect reference layer of the layer with index B when the layer with index C is a reference layer of the layer with index B, and the layer with index A is an indirect reference layer of the layer with index B when the layer with index A is not a direct reference layer of the layer with index B. A reference layer includes either a direct reference layer or an indirect reference layer. Furthermore, the fact that the layer with index A is a direct reference layer of the layer with index B means that the layer with index A contains at least one reference picture of a picture in the layer with index B. In step S702, if the value of the reference layer syntax element specifies that the layer with index j is a reference layer of the layer with index k, and the layer with index k is a direct reference layer of the layer with index i, then the layer with index j is a reference layer of the layer with index i.

[0354] S703 If the condition is met, predict the picture of the layer having index i based on the layer having index j, and the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, and the condition includes that the layer having index j is the reference layer of the layer having index i.

[0355] Specifically, if the layer with index j is a reference layer of the layer with index i, the picture of the layer with index i can be predicted based on the layer with index j, and the value of the chroma format-related syntax element applied to the layer with index i is the same as the value of the chroma format-related syntax element applied to the layer with index j.

[0356] Specifically, a device for decoding a coded video bitstream (e.g., the decoder 30 shown in Figure 3) is configured to use interpretation on the picture of the layer having index i based on the layer having index j, and to generate prediction blocks 365 for the video blocks of the current video slice based on motion vectors and other syntax elements received from the entropy decoding unit 304. For interpretation, the prediction blocks may be generated from one of the reference pictures in one of the reference picture lists. The video decoder 30 may configure reference frame lists, i.e., list 0 and list 1, using default configuration techniques based on the reference pictures stored in the DPB 330. The same or similar may be applied to tile groups (e.g., video tile groups) and / or tiles (e.g., video tiles) in addition to or as an alternative to slices (e.g., video slices), and may be applied depending on the embodiment using them, for example, video may be coded using I, P, or B tile groups and / or tiles.

[0357] Specifically, inter-layer prediction uses inter-prediction for the picture in the layer having index i, based on the reference picture from the layer having index j.

[0358] In this embodiment, the chroma format-related syntax elements are sequence parameter set (SPS) level syntax elements, where the SPS is applied to a layer having index j or a layer having index i.

[0359] Specifically, SPS is applied to picture sequences, layers are picture sequences, and SPS is applied to layers having index j or layers having index i.

[0360] In this embodiment, the syntax element related to the chroma format may also be the syntax element chroma_format_idc in the SPS table described above.

[0361] chroma_format_idc specifies chroma sampling for luma sampling, as specified in Section 6.2.

[0362] The meanings of chroma_format_idc and separate_colour_plane_flag are used to indicate the chroma format. [Table 8]

[0363] According to embodiments of this application, a reference layer syntax element is obtained by parsing a coded video bitstream, the value of which specifies whether the layer having index k is a direct reference layer of the layer having index i, where both i and k are integers and greater than or equal to 0, and based on the value of the reference layer syntax element, it is determined whether the layer having index j is a reference layer of the layer having index i, where the layer having index j is a reference layer of the layer having index k, where j is an integer and greater than or equal to 0, and if the condition is met, the picture of the layer having index i is predicted based on the layer having index j, the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, the condition including that the layer having index j is a reference layer of the layer having index i, and thus constraints on the format of the current layer and reference layer for inter-layer prediction are achieved, thereby simplifying the design.

[0364] Figure 8 is a schematic flowchart showing a method for decoding a coded video bitstream according to an embodiment of the present application, which may be performed by an apparatus for decoding a coded video bitstream, and as shown in Figure 8, the method for decoding a coded video bitstream may include the following steps 801 to 803.

[0365] S801 By parsing the coded video bitstream, a reference layer syntax element is obtained, the value of which specifies whether the layer with index j is a direct reference layer of the layer with index i, and both i and j are integers and greater than or equal to 0.

[0366] S802 If the condition is met, predict the picture of the layer having index i based on the layer having index j, and the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, the condition including the value of the reference layer syntax element specifying that the layer having index j is a direct reference layer of the layer having index i.

[0367] If the value of the reference layer syntax element specifies that the layer with index j is not a direct reference layer of the layer with index i, it should be noted that the layer with index j may be a reference layer, meaning that the layer with index j may be an indirect reference layer or a reference layer of the layer with index j.

[0368] According to embodiments of this application, a reference layer syntax element is obtained by parsing a coded video bitstream, the value of which specifies whether the layer having index j is a direct reference layer of the layer having index i, both i and j being integers and greater than or equal to 0, and if the condition is met, the picture of the layer having index i is predicted based on the layer having index j, the value of which is a chroma format related syntax element applied to the layer having index i is the same as the value of which is a chroma format related syntax element applied to the layer having index j, the condition being that the value of which is a reference layer syntax element specifies that the layer having index j is a direct reference layer of the layer having index i, thereby achieving constraints on the format of the current layer and the reference layer for inter-layer prediction, thereby simplifying the design.

[0369] A method for decoding a coded video bitstream, based on the embodiments shown in Figures 7 and 8, is: The step of obtaining a chroma format-related syntax element applied to a layer having index i and a chroma format-related syntax element applied to a layer having index j by parsing a coded video bitstream, further comprising the condition that the value of the chroma format-related syntax element applied to the layer having index i is the same as the value of the chroma format-related syntax element applied to the layer having index j.

[0370] Specifically, when the layer with index j is the reference layer of the layer with index i, and the value of the chroma format-related syntax element applied to the layer with index i is the same as the value of the chroma format-related syntax element applied to the layer with index j, then the picture of the layer with index i can be predicted based solely on the layer with index j.

[0371] Figure 9 is a schematic flowchart showing a method for decoding a coded video bitstream according to an embodiment of the present application, which may be performed by an apparatus for decoding a coded video bitstream, and as shown in Figure 9, a method for decoding a coded video bitstream based on the method shown in Figure 7 may include the following steps 901 to 906.

[0372] S901 By parsing the coded video bitstream, a reference layer syntax element is obtained, the value of which specifies whether the layer with index k is a direct reference layer of the layer with index i, and both i and k are integers and greater than or equal to 0.

[0373] S902 Based on the value of the reference layer syntax element, it is determined whether the layer having index j is a reference layer of the layer having index i. If the layer having index j is a reference layer of the layer having index k, then j is an integer and greater than or equal to 0.

[0374] S903 If the condition is met, predict the picture of the layer having index i based on the layer having index j, the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, and the condition includes that the layer having index j is the reference layer of the layer having index i.

[0375] S904 If the layer having index j is the reference layer of the layer having index i, and the value of the chroma format-related syntax element applied to the layer having index i is not the same as the value of the chroma format-related syntax element applied to the layer having index j, then decoding the coded video bitstream is stopped.

[0376] S905 If the layer with index j is not the reference layer of the layer with index i, predict the picture of the layer with index i without using the layer with index j.

[0377] Specifically, if the layer with index j is not a direct reference layer of the layer with index i, the layer with index k cannot be found by traversing all layers, the layer with index k is a direct reference layer of the layer with index i, and the layer with index j is a reference layer of the layer with index k, then it is determined that the layer with index j is not a reference layer of the layer with index i.

[0378] In this embodiment, if the layer having index j is not a direct reference layer of the layer having index i, it is determined whether the layer having index j is an indirect reference layer of the layer having index i. If the layer having index j is an indirect reference layer of the layer having index i, the picture of the layer having index i is predicted using the layer having index j. If the layer having index j is not an indirect reference layer of the layer having index i, the picture of the layer having index i is predicted without using the layer having index j.

[0379] When a layer with index k is a direct reference layer of the layer with index i, and a layer with index j is a reference layer of the layer with index k by traversing all layers, then the layer with index j is determined to be an indirect layer of the layer with index i.

[0380] If condition S906 is met, the value of the chroma format-related syntax element applied to the layer with index i is determined to be the value of the chroma format-related syntax element applied to the layer with index j, without obtaining the chroma format-related syntax element applied to the layer with index i by parsing the coded video bitstream.

[0381] Specifically, when the layer having index j is a reference layer of the layer having index i, the value of the chroma format-related syntax element applied to the layer having index i is determined to be the value of the chroma format-related syntax element applied to the layer having index j, without obtaining the chroma format-related syntax element applied to the layer having index i by parsing the coded video bitstream.

[0382] According to embodiments of this application, if the layer having index j is a reference layer of the layer having index i, and the value of the chroma format-related syntax element applied to the layer having index i is not the same as the value of the chroma format-related syntax element applied to the layer having index j, decoding of the coded video bitstream is stopped. If the layer having index j is not a reference layer of the layer having index i, the picture of the layer having index i is predicted without using the layer having index j. If the conditions are met, the value of the chroma format-related syntax element applied to the layer having index i is determined to be the same as the value of the chroma format-related syntax element applied to the layer having index j, without obtaining the chroma format-related syntax element applied to the layer having index i by parsing the coded video bitstream, thereby achieving format constraints on the current layer and reference layer for inter-layer prediction, thereby simplifying the design.

[0383] Figure 10 is a schematic flowchart showing a method for decoding a coded video bitstream according to an embodiment of the present application, which may be performed by an apparatus for decoding a coded video bitstream, and as shown in Figure 10, the method for decoding a coded video bitstream may include the following steps 1001 to 1003.

[0384] S1001 By parsing the coded video bitstream, a reference layer syntax element is obtained, the value of which specifies whether the layer with index k is a direct reference layer of the layer with index i, and both i and k are integers and greater than or equal to 0.

[0385] In this embodiment, the reference layer syntax element is a video parameter set (VPS) level syntax element, where the VPS is applied to the layer having index j and the layer having index i.

[0386] S1002 Based on the value of the reference layer syntax element, it is determined whether the layer having index j is the reference layer of the layer having index i. The layer having index j is the reference layer of the layer having index k, and j is an integer and greater than or equal to 0.

[0387] In this embodiment, if the value of the reference layer syntax element specifies that the layer having index k is a direct reference layer of the layer having index i, then the layer having index j is a reference layer of the layer having index i.

[0388] S1003 If the condition is met, predict the picture of the layer having index i based on the layer having index j, the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j, and the condition includes that the layer having index j is the reference layer of the layer having index i.

[0389] In the embodiment, bit depth-related syntax elements specify the bit depth of the luma and chroma samples of a picture in the layer to which the bit depth-related syntax elements are applied.

[0390] In this embodiment, the bit depth-related syntax element is a sequence parameter set (SPS) level syntax element, where the SPS is applied to a layer having index j or a layer having index i.

[0391] In this embodiment, the bit depth-related syntax element may also be the bit_depth_minus8 syntax element in the SPS table described above.

[0392] bit_depth_minus8 specifies the bit depth BitDepth of the samples in the luma and chroma arrays, and the value QpBdOffset of the luma and chroma quantization parameter range offset, as follows:

number

[0393] The principle of this embodiment is the same as that of the embodiment shown in Figure 7, and will not be explained here for brevity.

[0394] According to embodiments of this application, a reference layer syntax element is obtained by parsing a coded video bitstream, the value of which specifies whether the layer having index k is a direct reference layer of the layer having index i, where both i and k are integers and greater than or equal to 0, and based on the value of the reference layer syntax element, it is determined whether the layer having index j is a reference layer of the layer having index i, where the layer having index j is a reference layer of the layer having index k, where j is an integer and greater than or equal to 0, and if the condition is met, the picture of the layer having index i is predicted based on the layer having index j, the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j, the condition including that the layer having index j is a reference layer of the layer having index i, the constraints on the format of the current layer and reference layer for inter-layer prediction are achieved, thereby simplifying the design.

[0395] Figure 11 is a schematic flowchart showing a method for decoding a coded video bitstream according to an embodiment of the present application, which may be performed by an apparatus for decoding a coded video bitstream, and as shown in Figure 11, the method for decoding a coded video bitstream may include the following steps 1101 to 1102.

[0396] S1101 By parsing the coded video bitstream, a reference layer syntax element is obtained, the value of which specifies whether the layer with index j is a direct reference layer of the layer with index i, and both i and j are integers and greater than or equal to 0.

[0397] S1102 If the condition is met, predict the picture of the layer having index i based on the layer having index j, the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j, the condition includes the value of the reference layer syntax element specifying that the layer having index j is a direct reference layer of the layer having index i.

[0398] The principle of this embodiment is the same as that of the embodiment shown in Figure 8, and will not be explained here for brevity.

[0399] According to embodiments of this application, the reference layer syntax element is obtained by parsing a coded video bitstream, the value of which specifies whether the layer having index j is a direct reference layer of the layer having index i, both i and j being integers and greater than or equal to 0, and if the condition is met, the picture of the layer having index i is predicted based on the layer having index j, the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j, the condition includes the value of the reference layer syntax element specifying that the layer having index j is a direct reference layer of the layer having index i, the constraints on the format of the current layer and reference layer for inter-layer prediction are met, and the design is simplified.

[0400] A method for decoding a coded video bitstream, based on the embodiments shown in Figures 10 and 11, is: The step of obtaining bit depth-related syntax elements applied to a layer having index i and bit depth-related syntax elements applied to a layer having index j by parsing a coded video bitstream, further comprising the condition that the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j.

[0401] Figure 12 is a schematic flowchart showing a method for decoding a coded video bitstream according to an embodiment of the present application, which may be performed by an apparatus for decoding a coded video bitstream, and as shown in Figure 12, a method for decoding a coded video bitstream based on the method shown in Figure 10 may include the following steps 1201 to 1206.

[0402] S1201 By parsing the coded video bitstream, a reference layer syntax element is obtained, the value of which specifies whether the layer with index k is a direct reference layer of the layer with index i, and both i and k are integers and greater than or equal to 0.

[0403] S1202 Based on the value of the reference layer syntax element, it is determined whether the layer having index j is the reference layer of the layer having index i. The layer having index j is the reference layer of the layer having index k, and j is an integer and greater than or equal to 0.

[0404] S1203 If the condition is met, predict the picture of the layer having index i based on the layer having index j, the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j, and the condition includes that the layer having index j is the reference layer of the layer having index i.

[0405] S1204 If the layer having index j is the reference layer of the layer having index i, and the value of the bit depth-related syntax element applied to the layer having index i is not the same as the value of the bit depth-related syntax element applied to the layer having index j, then decode the coded video bitstream.

[0406] S1205 If the layer with index j is not the reference layer of the layer with index i, predict the picture of the layer with index i without using the layer with index j.

[0407] If condition S1206 is met, the value of the bit depth-related syntax element applied to the layer having index i is determined to be the value of the bit depth-related syntax element applied to the layer having index j, without obtaining the bit depth-related syntax element applied to the layer having index i by parsing the coded video bitstream.

[0408] The principle of this embodiment is the same as that of the embodiment shown in Figure 9, and will not be explained here for brevity.

[0409] According to embodiments of this application, if the layer having index j is a reference layer of the layer having index i, and the value of the bit depth-related syntax element applied to the layer having index i is not the same as the value of the bit depth-related syntax element applied to the layer having index j, decoding of the coded video bitstream is stopped. If the layer having index j is not a reference layer of the layer having index i, the picture of the layer having index i is predicted without using the layer having index j. If the conditions are met, the value of the bit depth-related syntax element applied to the layer having index i is determined to be the same as the value of the bit depth-related syntax element applied to the layer having index j, without obtaining the bit depth-related syntax element applied to the layer having index i by parsing the coded video bitstream, thereby achieving constraints on the format of the current layer and reference layer for inter-layer prediction, thereby simplifying the design.

[0410] Figure 13 is a schematic flowchart showing a method for encoding video according to an embodiment of the present application, which may be performed by a device for encoding video, and as shown in Figure 13, the method for encoding video may include the following steps 1301 to 1302.

[0411] S1301 Determine whether the layer having index j is a direct reference layer of the layer having index i, where both i and j are integers and greater than or equal to 0.

[0412] A device for encoding video (for example, the encoder 20 shown in Figure 2) may be configured to determine, for example, whether a layer having index j is a direct reference layer of a layer having index i, to select a reference block from multiple reference blocks of the same or different pictures of multiple other pictures, and to provide the reference picture (or reference picture index) and / or the position (x, y coordinates) of the reference block and the offset (spatial offset) between the current block's position as interprediction parameters to the motion estimation unit.

[0413] S1302 If the layer having index j is a direct reference layer of the layer having index i, a reference layer syntax element having a value that specifies that the layer having index j is a direct reference layer of the layer having index i is encoded into the video bitstream, the chroma format related syntax element applied to the layer having index i and the chroma format related syntax element applied to the layer having index j are encoded into the video bitstream, and the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j.

[0414] In this embodiment, the reference layer syntax element may also be the syntax element vps_direct_ref_layer_flag[i][j] in the VPS table described above.

[0415] A vps_direct_ref_layer_flag[i][j] equal to 0 indicates that the layer with index j is not a direct reference layer of the layer with index i. A vps_direct_ref_layer_flag[i][j] equal to 1 indicates that the layer with index j is a direct reference layer of the layer with index i. For i and j in the range of 0 or greater and less than or equal to vps_max_layers_minus1, if vps_direct_ref_layer_flag[i][j] does not exist, it is assumed to be equal to 0. When vps_independent_layer_flag[i] is equal to 0, there must be at least one value of j in the range of 0 or greater and less than or equal to i-1 such that vps_direct_ref_layer_flag[i][j] is equal to 1.

[0416] The variables NumDirectRefLayers[i], DirectRefLayerIdx[i][d], NumRefLayers[i], RefLayerIdx[i][r], and LayerUsedAsRefLayerFlag[j] are derived as follows:

number

[0417] In this embodiment, the syntax element related to the chroma format may also be the syntax element chroma_format_idc in the SPS table described above.

[0418] chroma_format_idc specifies chromasampling for lumasampling, as specified in Section 6.2.

[0419] The meanings of chroma_format_idc and separate_colour_plane_flag are used to indicate the chroma format. [Table 9]

[0420] Specifically, the device for encoding video (for example, encoder 20 in Figure 2) encodes a reference layer syntax element into a video bitstream that has a value specifying that the layer having index j is a direct reference layer of the layer having index i, encodes chroma format-related syntax elements applied to the layer having index i and chroma format-related syntax elements applied to the layer having index j into a video bitstream, and encodes the quantization coefficient 209, inter-prediction parameter, intra-prediction parameter, loop filter parameter and / or other syntax elements, for example, an entropy coding algorithm or scheme (e.g., variable length coding (VLC), context adaptive VLC scheme (CAVLC), arithmetic coding scheme, binarization, context adaptive binary arithmetic coding (CABAC), syntax-based context-adaptive binary arithmetic coding (SBAC), probability interval partitioning entropy (PIPE)). The system is configured to obtain encoded picture data 21 that can be output via output 272 in the form of an encoded bitstream 21, by applying or circumventing (uncompressing) entropy coding or other entropy coding methods or techniques, so that a device for decoding the encoded bitstream (e.g., a video decoder 30 shown in Figure 3) may receive and use parameters for decoding. The encoded bitstream 21 may be transmitted to the video decoder 30 or stored in memory for later transmission or retrieval by the video decoder 30.

[0421] According to embodiments of the present invention, it is determined whether a layer having index j is a direct reference layer of a layer having index i, where both i and j are integers and greater than or equal to 0. If the layer having index j is a direct reference layer of a layer having index i, a reference layer syntax element having a value specifying that the layer having index j is a direct reference layer of a layer having index i is encoded into a video bitstream. A chroma format-related syntax element applied to the layer having index i and a chroma format-related syntax element applied to the layer having index j are encoded into a video bitstream, where the value of the chroma format-related syntax element applied to the layer having index i is the same as the value of the chroma format-related syntax element applied to the layer having index j, thereby achieving constraints on the format of the current layer and reference layer for inter-layer prediction, and thereby simplifying the design.

[0422] Figure 14 is a schematic flowchart showing a method for encoding video according to an embodiment of the present application, which may be performed by a device for encoding video, and as shown in Figure 14, a method for encoding video based on the method shown in Figure 13 may include the following steps 1401 to 1404.

[0423] S1401 Determine whether the layer having index j is a direct reference layer of the layer having index i, where both i and j are integers and greater than or equal to 0.

[0424] S1402 If the layer having index j is a direct reference layer of the layer having index i, a reference layer syntax element having a value that specifies that the layer having index j is a direct reference layer of the layer having index i is encoded into the video bitstream, the chroma format related syntax element applied to the layer having index i and the chroma format related syntax element applied to the layer having index j are encoded into the video bitstream, and the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j.

[0425] S1403 If the layer with index j is a direct reference layer of the layer with index i, predict the picture of the layer with index i based on the layer with index j.

[0426] The set of interpretation modes (or possible ones) depends on the available reference picture (i.e., a previously decoded picture, e.g., one stored in DBP) and other interpretation parameters, e.g., whether the entire reference picture or only a portion of the reference picture is used, e.g., whether the search window area around the current block's region is used to search for the best-matching reference block, and / or whether pixel interpolation, e.g., half / semi-per, 1 / 4-per and / or 1 / 16-per interpolation is applied.

[0427] S1404 If the layer with index j is not the reference layer of the layer with index i, predict the picture of the layer with index i without using the layer with index j.

[0428] In this embodiment, if the layer having index j is not a direct reference layer of the layer having index i, it is determined whether the layer having index j is an indirect reference layer of the layer having index i. If the layer having index j is an indirect reference layer of the layer having index i, the picture of the layer having index i is predicted using the layer having index j. If the layer having index j is not an indirect reference layer of the layer having index i, the picture of the layer having index i is predicted without using the layer having index j.

[0429] According to embodiments of the present invention, it is determined whether a layer having index j is a direct reference layer of a layer having index i, where both i and j are integers and greater than or equal to 0. If the layer having index j is a direct reference layer of a layer having index i, a reference layer syntax element having a value that specifies that the layer having index j is a direct reference layer of a layer having index i is encoded into a video bitstream. A chroma format-related syntax element applied to the layer having index i and a chroma format-related syntax element applied to the layer having index j are encoded into a video bitstream, where the value of the chroma format-related syntax element applied to the layer having index i is the same as the value of the chroma format-related syntax element applied to the layer having index j. If the layer having index j is a direct reference layer of a layer having index i, the picture of the layer having index i is predicted based on the layer having index j, thereby achieving constraints on the format of the current layer and the reference layer for inter-layer prediction, and thereby simplifying the design.

[0430] Figure 15 is a schematic flowchart showing a method for encoding video according to an embodiment of the present application, which may be performed by a device for encoding video, and as shown in Figure 15, the method for encoding video may include the following steps 1501 to 1502.

[0431] S1501 Determine whether the layer having index j is a direct reference layer of the layer having index i, where both i and j are integers and greater than or equal to 0.

[0432] S1502 If the layer having index j is a direct reference layer of the layer having index i, encode a reference layer syntax element in the video bitstream that has a value specifying that the layer having index j is a direct reference layer of the layer having index i, encode the bit depth-related syntax element applied to the layer having index i and the bit depth-related syntax element applied to the layer having index j in the video bitstream, and the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j.

[0433] In the embodiment, bit depth-related syntax elements specify the bit depth of the luma and chroma samples of a picture in the layer to which the bit depth-related syntax elements are applied.

[0434] In this embodiment, the bit depth-related syntax element may also be the bit_depth_minus8 syntax element in the SPS table described above.

[0435] bit_depth_minus8 specifies the bit depth BitDepth of the samples in the luma and chroma arrays, and the value QpBdOffset of the luma and chroma quantization parameter range offset, as follows:

number

[0436] The principle of this embodiment is the same as that of the embodiment shown in Figure 13, and will not be explained here for brevity.

[0437] According to the embodiments of this application, in the embodiments, the bit depth-related syntax element may also be the syntax element bit_depth_minus8 in the above SPS table.

[0438] bit_depth_minus8 specifies the bit depth BitDepth of the samples in the luma and chroma arrays, and the value QpBdOffset of the luma and chroma quantization parameter range offset, as follows:

number

[0439] The principle of this embodiment is the same as that of the embodiment shown in Figure 7, and will not be explained here for brevity.

[0440] According to embodiments of the present invention, it is determined whether a layer having index j is a direct reference layer of a layer having index i, and both i and j are integers and greater than or equal to 0. If the layer having index j is a direct reference layer of a layer having index i, a reference layer syntax element having a value that specifies that the layer having index j is a direct reference layer of a layer having index i is encoded into a video bitstream. A bit depth-related syntax element applied to the layer having index i and a bit depth-related syntax element applied to the layer having index j are encoded into a video bitstream, the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j, the constraints on the format of the current layer and reference layer for inter-layer prediction are achieved, thereby simplifying the design.

[0441] Figure 16 is a schematic flowchart showing a method for encoding video according to an embodiment of the present application, which may be performed by a device for encoding video, and as shown in Figure 16, a method for encoding video based on the method shown in Figure 15 may include the following steps 1601 to 1604.

[0442] S1601 Determine whether the layer having index j is a direct reference layer of the layer having index i, where both i and j are integers and greater than or equal to 0.

[0443] S1602 If the layer having index j is a direct reference layer of the layer having index i, encode a reference layer syntax element having a value that specifies that the layer having index j is a direct reference layer of the layer having index i into a video bitstream, encode the bit depth-related syntax element applied to the layer having index i and the bit depth-related syntax element applied to the layer having index j into a video bitstream, and the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j.

[0444] S1603 If the layer with index j is a direct reference layer of the layer with index i, predict the picture of the layer with index i based on the layer with index j.

[0445] S1604 If the layer with index j is not the reference layer of the layer with index i, predict the picture of the layer with index i without using the layer with index j.

[0446] According to embodiments of the present invention, it is determined whether a layer having index j is a direct reference layer of a layer having index i, where both i and j are integers and greater than or equal to 0. If the layer having index j is a direct reference layer of a layer having index i, a reference layer syntax element having a value that specifies that the layer having index j is a direct reference layer of a layer having index i is encoded into a video bitstream. A bit depth-related syntax element applied to the layer having index i and a bit depth-related syntax element applied to the layer having index j are encoded into a video bitstream, where the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j. If the layer having index j is a direct reference layer of a layer having index i, the picture of the layer having index i is predicted based on the layer having index j, thereby achieving constraints on the format of the current layer and the reference layer for inter-layer prediction, and thereby simplifying the design.

[0447] Figure 17 is a structural diagram showing an apparatus for decoding a coded video bitstream according to an embodiment of the present application, and as shown in Figure 17, the apparatus for decoding a coded video bitstream may include an acquisition unit 1701, a determination unit 1702, and a prediction unit 1703.

[0448] The acquisition unit 1701 is configured to acquire a reference layer syntax element by parsing a coded video bitstream, the value of which specifies whether the layer having index k is a direct reference layer of the layer having index i, and both i and k are integers and greater than or equal to 0.

[0449] The determination unit 1702 is configured to determine whether a layer having index j is a reference layer of a layer having index i, based on the value of the reference layer syntax element, and the layer having index j is a reference layer of a layer having index k, where j is an integer and is greater than or equal to 0.

[0450] The prediction unit 1703 is configured to predict a picture of a layer having index i based on a layer having index j, provided that the following conditions are met: the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, and the condition includes that the layer having index j is a reference layer of the layer having index i.

[0451] In this embodiment, if the value of the reference layer syntax element specifies that the layer having index k is a direct reference layer of the layer having index i, then the layer having index j is a reference layer of the layer having index i.

[0452] In this embodiment, the reference layer syntax element is a video parameter set (VPS) level syntax element, where the VPS is applied to the layer having index j and the layer having index i.

[0453] In this embodiment, the chroma format-related syntax elements are sequence parameter set (SPS) level syntax elements, where the SPS is applied to a layer having index j or a layer having index i.

[0454] The acquisition unit 1701 may be or may be included in the entropy decoding unit 304 of the decoder 30 in Figure 3, the decision unit 1702 may be or may be included in the mode application unit 360 of the decoder 30 in Figure 3, and the prediction unit 1703 may be or may be included in the interprediction unit 344 of the decoder 30 in Figure 3.

[0455] It should be noted that the acquisition unit 1701, the decision unit 1702, and the prediction unit 1703 may be software modules or hardware circuits.

[0456] The apparatus for decoding the coded video bitstream in this embodiment may be configured to perform the method shown in Figure 7, and the apparatus for decoding the coded video bitstream related to the method shown in Figure 7 may also be configured in the same way as the apparatus for decoding the coded video bitstream shown in Figure 17, which will not be described again here for brevity.

[0457] Figure 18 is a structural diagram showing an apparatus for decoding a coded video bitstream according to an embodiment of the present application, and as shown in Figure 18, the apparatus for decoding a coded video bitstream may include an acquisition unit 1801 and a prediction unit 1802.

[0458] The acquisition unit 1801 is configured to acquire a reference layer syntax element by parsing a coded video bitstream, the value of which specifies whether the layer having index j is a direct reference layer of the layer having index i, and both i and j are integers and greater than or equal to 0.

[0459] The prediction unit 1802 is configured to predict a picture of a layer having index i based on a layer having index j, provided that the conditions are met, the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, and the conditions include the value of the reference layer syntax element specifying that the layer having index j is a direct reference layer of the layer having index i.

[0460] The acquisition unit 1801 may be or may be included in the entropy decoding unit 304 of the decoder 30 in Figure 3, and the prediction unit 1802 may be or may be included in the interprediction unit 344 of the decoder 30 in Figure 3.

[0461] It should be noted that the acquisition unit 1801 and the prediction unit 1802 may be software modules or hardware circuits.

[0462] The apparatus for decoding the coded video bitstream in this embodiment may be configured to perform the method shown in Figure 8, and the apparatus for decoding the coded video bitstream related to the method shown in Figure 8 may also be configured in the same way as the apparatus for decoding the coded video bitstream shown in Figure 18, which will not be described again here for brevity.

[0463] Based on the embodiments shown in Figures 17 and 18, the acquisition unit 1701 or acquisition unit 1801 is further configured to acquire a chroma format-related syntax element applied to a layer having index i and a chroma format-related syntax element applied to a layer having index j by parsing a coded video bitstream, the condition further comprising that the value of the chroma format-related syntax element applied to the layer having index i is the same as the value of the chroma format-related syntax element applied to the layer having index j.

[0464] Figure 19 is a structural diagram showing an apparatus for decoding a coded video bitstream according to an embodiment of the present application. As shown in Figure 19, based on the apparatus shown in Figure 17, the apparatus for decoding a coded video bitstream may include an acquisition unit 1701, a determination unit 1702, a prediction unit 1703, and a stop unit 1704.

[0465] The stop unit 1704 is configured to stop decoding the coded video bitstream if the layer having index j is a reference layer of the layer having index i, and the value of the chroma format related syntax element applied to the layer having index i is not the same as the value of the chroma format related syntax element applied to the layer having index j.

[0466] The prediction unit 1703 is further configured to predict the picture of the layer having index i without using the layer having index j if the layer having index j is not the reference layer of the layer having index i.

[0467] The decision unit 1702 is further configured to determine, if the conditions are met, that the value of the chroma format-related syntax element applied to the layer having index i is the value of the chroma format-related syntax element applied to the layer having index j, without obtaining the chroma format-related syntax element applied to the layer having index i by parsing the coded video bitstream.

[0468] In this embodiment, the stop unit 1704 may be the entropy decoding unit 304 of the decoder 30 in Figure 3, or may be included therein.

[0469] It should be noted that the acquisition unit 1701, decision unit 1702, prediction unit 1703, and stop unit 1704 may be software modules or hardware circuits.

[0470] The apparatus for decoding the coded video bitstream in this embodiment may be configured to perform the method shown in Figure 9, and the apparatus for decoding the coded video bitstream related to the method shown in Figure 9 may also be configured in the same way as the apparatus for decoding the coded video bitstream shown in Figure 19, which will not be described again here for brevity.

[0471] Figure 20 is a structural diagram showing an apparatus for decoding a coded video bitstream according to an embodiment of the present application, and as shown in Figure 20, the apparatus for decoding a coded video bitstream may include an acquisition unit 2001, a decision unit 2002, and a prediction unit 2003.

[0472] The acquisition unit 2001 is configured to acquire a reference layer syntax element by parsing a coded video bitstream, the value of which specifies whether the layer having index k is a direct reference layer of the layer having index i, and both i and k are integers and greater than or equal to 0.

[0473] The decision unit 2002 is configured to determine whether a layer having index j is a reference layer of a layer having index i, based on the value of the reference layer syntax element, and the layer having index j is a reference layer of a layer having index k, where j is an integer and is greater than or equal to 0.

[0474] The prediction unit 2003 is configured to predict a picture of a layer having index i based on a layer having index j, provided that the following conditions are met: the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j, and the condition includes that the layer having index j is a reference layer of the layer having index i.

[0475] In this embodiment, if the value of the reference layer syntax element specifies that the layer having index k is a direct reference layer of the layer having index i, then the layer having index j is a reference layer of the layer having index i.

[0476] In the embodiment, bit depth-related syntax elements specify the bit depth of the luma and chroma samples of a picture in the layer to which the bit depth-related syntax elements are applied.

[0477] In this embodiment, the reference layer syntax element is a video parameter set (VPS) level syntax element, where the VPS is applied to the layer having index j and the layer having index i.

[0478] In this embodiment, the bit depth-related syntax element is a sequence parameter set (SPS) level syntax element, where the SPS is applied to a layer having index j or a layer having index i.

[0479] The acquisition unit 2001 may be or may be included in the entropy decoding unit 304 of the decoder 30 in Figure 3, the decision unit 2002 may be or may be included in the mode application unit 360 of the decoder 30 in Figure 3, and the prediction unit 2003 may be or may be included in the interprediction unit 344 of the decoder 30 in Figure 3.

[0480] It should be noted that the acquisition unit 2001, the decision unit 2002, and the prediction unit 2003 may be software modules or hardware circuits.

[0481] The apparatus for decoding the coded video bitstream in this embodiment may be configured to perform the method shown in Figure 10, and the apparatus for decoding the coded video bitstream related to the method shown in Figure 10 may also be configured in the same way as the apparatus for decoding the coded video bitstream shown in Figure 20, which will not be described again here for brevity.

[0482] Figure 21 is a structural diagram showing an apparatus for decoding a coded video bitstream according to an embodiment of the present application, and as shown in Figure 21, the apparatus for decoding a coded video bitstream may include an acquisition unit 2101 and a prediction unit 2102.

[0483] The acquisition unit 2101 is configured to acquire a reference layer syntax element by parsing the coded video bitstream, the value of which specifies whether the layer having index j is a direct reference layer of the layer having index i, and both i and j are integers and greater than or equal to 0.

[0484] The prediction unit 2102 is configured to predict a picture of a layer having index i based on a layer having index j, provided that the conditions are met, the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j, and the conditions include the value of the reference layer syntax element specifying that the layer having index j is a direct reference layer of the layer having index i.

[0485] The acquisition unit 2101 may be or may be included in the entropy decoding unit 304 of the decoder 30 in Figure 3, and the prediction unit 2102 may be or may be included in the interprediction unit 344 of the decoder 30 in Figure 3.

[0486] It should be noted that the acquisition unit 2101 and the prediction unit 2102 may be software modules or hardware circuits.

[0487] The apparatus for decoding the coded video bitstream in this embodiment may be configured to perform the method shown in Figure 11, and the apparatus for decoding the coded video bitstream related to the method shown in Figure 11 may also be configured in the same way as the apparatus for decoding the coded video bitstream shown in Figure 21, which will not be described again here for brevity.

[0488] Based on the embodiments shown in Figures 20 and 21, the acquisition unit 2001 or acquisition unit 2101 is further configured to acquire bit depth-related syntax elements applied to the layer having index i and bit depth-related syntax elements applied to the layer having index j by parsing a coded video bitstream, the condition further comprising that the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j.

[0489] Figure 22 is a structural diagram showing an apparatus for decoding a coded video bitstream according to an embodiment of the present application. As shown in Figure 22, based on the apparatus shown in Figure 20, the apparatus for decoding a coded video bitstream may include an acquisition unit 2001, a decision unit 2002, a prediction unit 2003, and a stop unit 2004.

[0490] The stop unit 2004 is configured to stop decoding the coded video bitstream if the layer having index j is a reference layer of the layer having index i, and the value of the bit depth-related syntax element applied to the layer having index i is not the same as the value of the bit depth-related syntax element applied to the layer having index j.

[0491] The prediction unit 2003 is further configured to predict the picture of the layer having index i without using the layer having index j if the layer having index j is not the reference layer of the layer having index i.

[0492] The decision unit 2002 is further configured to determine that the value of the chroma format-related syntax element applied to the layer having index i is the value of the chroma format-related syntax element applied to the layer having index j, without obtaining the chroma format-related syntax element applied to the layer having index i by parsing the coded video bitstream.

[0493] In this embodiment, the stop unit 2004 may be the entropy decoding unit 304 of the decoder 30 in Figure 3, or may be included therein.

[0494] It should be noted that the acquisition unit 2001, decision unit 2002, prediction unit 2003, and stop unit 2004 may be software modules or hardware circuits.

[0495] The apparatus for decoding the coded video bitstream in this embodiment may be configured to perform the method shown in Figure 12, and the apparatus for decoding the coded video bitstream related to the method shown in Figure 12 may also be configured in the same way as the apparatus for decoding the coded video bitstream shown in Figure 22, which will not be described again here for brevity.

[0496] It should be noted that the apparatus for performing the methods shown in Figures 7-12 or the apparatus for decoding the coded video bitstream shown in Figures 17-22 may be or may be the destination device 14 in Figure 1A, the video decoder 30 in Figure 1B, the decoder 30 in Figure 3, the video coding device 400 in Figure 4, or the apparatus 500 in Figure 5.

[0497] Figure 23 is a structural diagram showing an apparatus for encoding video according to an embodiment of the present application, and as shown in Figure 23, the apparatus for encoding video may include a determination unit 2301 and an encoding unit 2302.

[0498] The decision unit 2301 is configured to determine whether a layer having index j is a direct reference layer of a layer having index i, where both i and j are integers and greater than or equal to 0.

[0499] The encoding unit 2302 is configured to encode a reference layer syntax element into a video bitstream that has a value specifying that the layer having index j is a direct reference layer of the layer having index i, if the layer having index j is a direct reference layer of the layer having index i, and to encode a chroma format related syntax element applied to the layer having index i and a chroma format related syntax element applied to the layer having index j into a video bitstream, wherein the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j.

[0500] The decision unit 2301 may be the mode selection unit 260 of the decoder 20 in Figure 2, or may be included therein, and the encoding unit 2302 may be the entropy encoding unit 270 of the encoder 20 in Figure 2, or may be included therein.

[0501] It should be noted that the decision unit 2301 and the encoding unit 2302 may be software modules or hardware circuits.

[0502] The apparatus for encoding video in this embodiment may be configured to perform the method shown in Figure 13, and the apparatus for encoding video related to the method shown in Figure 13 may also be configured in the same way as the apparatus for encoding video shown in Figure 23, which will not be described again here for brevity.

[0503] Figure 24 is a structural diagram showing an apparatus for encoding video according to an embodiment of the present application, and as shown in Figure 24, the apparatus for encoding video may further include a first prediction unit 2303 and a second prediction unit 2304, based on the apparatus shown in Figure 23.

[0504] The first prediction unit 2303 is configured to predict the picture of the layer having index i based on the layer having index j, if the layer having index j is a direct reference layer of the layer having index i.

[0505] The second prediction unit 2304 predicts the picture of the layer with index i without using the layer with index j if the layer with index j is not the reference layer of the layer with index i.

[0506] The first prediction unit 2303 and the second prediction unit 2304 may also be the interpretation unit 244 of the decoder 20 in Figure 2, or may be included therein.

[0507] It should be noted that the decision unit 2301, the coding unit 2302, the first prediction unit 2303, and the second prediction unit 2304 may be software modules or hardware circuits.

[0508] The apparatus for encoding video in this embodiment may be configured to perform the method shown in Figure 14, and the apparatus for encoding video related to the method shown in Figure 14 may also be configured in the same way as the apparatus for encoding video shown in Figure 24, which will not be described again here for brevity.

[0509] Figure 25 is a structural diagram showing an apparatus for encoding video according to an embodiment of the present application, and as shown in Figure 25, the apparatus for encoding video may include a determination unit 2501 and an encoding unit 2502.

[0510] The decision unit 2301 is configured to determine whether a layer having index j is a direct reference layer of a layer having index i, where both i and j are integers and greater than or equal to 0.

[0511] The encoding unit 2502 is configured to encode a reference layer syntax element into the video bitstream that specifies that the layer having index j is a direct reference layer of the layer having index i, if the layer having index j is a direct reference layer of the layer having index i, and to encode a bit depth-related syntax element applied to the layer having index i and a bit depth-related syntax element applied to the layer having index j into the video bitstream, wherein the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j.

[0512] In the embodiment, bit depth-related syntax elements specify the bit depth of the luma and chroma samples of a picture in the layer to which the bit depth-related syntax elements are applied.

[0513] The decision unit 2501 may be the mode selection unit 260 of the decoder 20 in Figure 2, or may be included therein, and the encoding unit 2502 may be the entropy encoding unit 270 of the encoder 20 in Figure 2, or may be included therein.

[0514] It should be noted that the decision unit 2501 and the encoding unit 2502 may be software modules or hardware circuits.

[0515] The apparatus for encoding video in this embodiment may be configured to perform the method shown in Figure 15, and the apparatus for encoding video related to the method shown in Figure 15 may also be configured in the same way as the apparatus for encoding video shown in Figure 25, which will not be described again here for brevity.

[0516] Figure 26 is a structural diagram showing an apparatus for encoding video according to an embodiment of the present application, and as shown in Figure 26, the apparatus for encoding video may further include a first prediction unit 2503 and a second prediction unit 2504, based on the apparatus shown in Figure 25.

[0517] The first prediction unit 2503 is configured to predict the picture of the layer having index i based on the layer having index j, if the layer having index j is a direct reference layer of the layer having index i.

[0518] The second prediction unit 2504 predicts the picture of the layer with index i without using the layer with index j if the layer with index j is not the reference layer of the layer with index i.

[0519] The first prediction unit 2503 and the second prediction unit 2504 may also be the interpretation unit 244 of the decoder 20 in Figure 2, or may be included therein.

[0520] It should be noted that the decision unit 2501, the coding unit 2502, the first prediction unit 2503, and the second prediction unit 2504 may be software modules or hardware circuits.

[0521] The apparatus for encoding video in this embodiment may be configured to perform the method shown in Figure 16, and the apparatus for encoding video related to the method shown in Figure 16 may also be configured in the same way as the apparatus for encoding video shown in Figure 26, which will not be described again here for brevity.

[0522] It should be noted that the apparatus for performing the methods shown in Figures 13-16 or the apparatus for encoding video shown in Figures 23-26 may also be, or may be included in, the source device 12 in Figure 1A, the video encoder 20 in Figure 1B, the encoder 20 in Figure 2, the video coding device 400 in Figure 4, or the apparatus 500 in Figure 5.

[0523] This application further provides an encoder including a processing circuit for performing a method according to any one of the embodiments of this application shown in Figures 13 to 16.

[0524] It should be noted that the encoder in this embodiment may be or may be the source device 12 in Figure 1A, the video encoder 20 in Figure 1B, the encoder 20 in Figure 2, the video coding device 400 in Figure 4, or the device 500 in Figure 5.

[0525] This application further provides a decoder including a processing circuit for performing a method according to any one of the embodiments of this application shown in Figures 7 to 12.

[0526] It should be noted that the decoder in this embodiment may be or may be the destination device 14 in Figure 1A, the video decoder 30 in Figure 1B, the decoder 30 in Figure 3, the video coding device 400 in Figure 4, or the device 500 in Figure 5.

[0527] This application further provides a computer program product that includes program code for performing a method according to any one of the embodiments of this application shown in Figures 7 to 16 when executed on a computer or processor.

[0528] The present application further provides a decoder comprising one or more processors and a non-temporary computer-readable storage medium coupled to the one or more processors and storing a program for execution by the processors, wherein the decoder, when executed by the processors, performs a method according to any one of the embodiments of the present application shown in Figures 7 to 12.

[0529] It should be noted that the decoder in this embodiment may be or may be the destination device 14 in Figure 1A, the video decoder 30 in Figure 1B, the decoder 30 in Figure 3, the video coding device 400 in Figure 4, or the device 500 in Figure 5.

[0530] The present application further provides an encoder comprising one or more processors and a non-temporary computer-readable storage medium coupled to the one or more processors and storing a program for execution by the processors, wherein the program, when executed by the processors, configures the encoder to perform a method according to any one of the embodiments of the present application shown in Figures 13 to 16.

[0531] It should be noted that the encoder in this embodiment may be or may be the source device 12 in Figure 1A, the video encoder 20 in Figure 1B, the encoder 20 in Figure 2, the video coding device 400 in Figure 4, or the device 500 in Figure 5.

[0532] This application further provides a non-temporary computer-readable medium for carrying program code that, when executed by a computer device, causes a computer device to execute one of the embodiments of the present invention.

[0533] This application further provides a non-temporary storage medium including an encoded bitstream decoded by a picture decoding device, wherein the bitstream includes encoded data of at least one layer, and further includes a chroma format-related syntax element of a layer having index i and a chroma format-related syntax element of a layer having index j, wherein when the layer having index j is a reference layer of the layer having index i, the value of the chroma format-related syntax element of the layer having index i is the same as the value of the chroma format-related syntax element of the layer having index j, and both i and j are integers and greater than or equal to 0.

[0534] This application further provides a non-temporary storage medium including an encoded bitstream decoded by a picture decoding device, wherein the bitstream includes encoded data of at least one layer, and further includes a bit depth-related syntax element of a layer having index i and a bit depth-related syntax element of a layer having index j, where the layer having index j is a reference layer of the layer having index i, the value of the bit depth-related syntax element of the layer having index i is the same as the value of the bit depth-related syntax element of the layer having index j, and both i and j are integers and greater than or equal to 0.

[0535] In the embodiment, bit depth-related syntax elements specify the bit depth of the luma and chroma samples of a picture in the layer to which the bit depth-related syntax elements are applied.

[0536] In the embodiment, the bitstream further includes a reference layer syntax element, wherein the value of the reference layer syntax element specifies that the layer having index j is a reference layer of the layer having index i, or that the layer having index j is a direct reference layer of the layer having index i.

[0537] The following are examples of the application of the encoding and decoding methods shown in the above embodiment, as well as systems using them.

[0538] Figure 27 is a block diagram showing a content supply system 3100 for realizing a content distribution service. This content supply system 3100 includes a capture device 3102 and a terminal device 3106, and optionally includes a display 3126. The capture device 3102 communicates with the terminal device 3106 over a communication link 3104. The communication link may include the communication channel 13 described above. The communication link 3104 includes, but is not limited to, Wi-Fi, Ethernet, cable, wireless (3G / 4G / 5G), USB, or any combination thereof.

[0539] The capture device 3102 may generate data and encode the data using an encoding method as shown in the above embodiment. Alternatively, the capture device 3102 may distribute the data to a streaming server (not shown in the drawings), which encodes the data and transmits the encoded data to the terminal device 3106. The capture device 3102 includes, but is not limited to, a camera, a smartphone or tablet, a computer or laptop, a video conferencing system, a PDA, an in-vehicle device, or any combination thereof. For example, the capture device 3102 may include the source device 12 as described above. When the data includes video, the video encoder 20 included in the capture device 3102 may actually perform video encoding. When the data includes audio (i.e., voice), the audio encoder included in the capture device 3102 may actually perform audio encoding. In some practical scenarios, the capture device 3102 distributes the encoded video and audio data by multiplexing them together. In other practical scenarios, for example in a video conferencing system, the encoded audio data and encoded video data are not multiplexed. The capture device 3102 separately distributes encoded audio data and encoded video data to the terminal device 3106.

[0540] In the content supply system 3100, the terminal device 310 receives and plays back encoded data. The terminal device 3106 may be any device with data reception and recovery capabilities, such as a smartphone or tablet 3108, a computer or laptop 3110, a network video recorder (NVR) / digital video recorder (DVR) 3112, a TV 3114, a set-top box (STB) 3116, a video conferencing system 3118, a video surveillance system 3120, a personal digital assistant (PDA) 3122, an in-vehicle device 3124, or any combination thereof, that can decode the above encoded data. For example, the terminal device 3106 may include the destination device 14 as described above. When the encoded data includes video, the video decoder 30 included in the terminal device is prioritized to perform video decoding. When the encoded data includes audio, the audio decoder included in the terminal device is prioritized to perform audio decoding.

[0541] In terminal devices with their own displays, such as smartphones or tablets 3108, computers or laptops 3110, network video recorders (NVRs) / digital video decoders (DVRs) 3112, TVs 3114, personal digital assistants (PDAs) 3122, or in-vehicle devices 3124, the terminal device can supply decoded data to its own display. In terminal devices without a display, such as STBs 3116, video conferencing systems 3118, or video surveillance systems 3120, an external display 3126 is made contact with the terminal device to receive and display the decoded data.

[0542] When each device in this system performs encoding or decoding, a picture encoding device or a picture decoding device can be used, as shown in the embodiment described above.

[0543] Figure 28 shows the structure of an example terminal device 3106. After the terminal device 3106 receives a stream from the capture device 3102, the protocol processing unit 3202 analyzes the transmission protocol of the stream. The protocol includes, but is not limited to, Real Time Streaming Protocol (RTSP), Hyper Text Transfer Protocol (HTTP), HTTP Live Streaming Protocol (HLS), MPEG-DASH, Real-time Transport Protocol (RTP), Real Time Messaging Protocol (RTMP), or any combination thereof.

[0544] After the protocol processing unit 3202 processes the stream, a stream file is generated. The file is output to the demultiplexing unit 3204. The demultiplexing unit 3204 can separate the multiplexed data into encoded audio data and encoded video data. As described above, in some real-world scenarios, for example in a video conferencing system, the encoded audio data and encoded video data are not multiplexed. In this situation, the encoded data is sent to the video decoder 3206 and audio decoder 3208 without passing through the demultiplexing unit 3204.

[0545] Through demultiplexing, a video elementary stream (ES), an audio ES, and an optional subtitle are generated. The video decoder 3206, including the video decoder 30 as described in the above embodiment, decodes the video ES using the decoding method shown in the above embodiment to generate video frames and supplies this data to the synchronization unit 3212. The audio decoder 3208 decodes the audio ES to generate audio frames and supplies this data to the synchronization unit 3212. Alternatively, the video frames may be stored in a buffer (not shown in Figure 28) before being supplied to the synchronization unit 3212. Similarly, the audio frames may be stored in a buffer (not shown in Figure 28) before being supplied to the synchronization unit 3212.

[0546] The synchronization unit 3212 synchronizes video frames and audio frames and supplies video / audio to the video / audio display 3214. For example, the synchronization unit 3212 synchronizes the presentation of video and audio information. The information may be coded in the syntax using timestamps for the presentation of coded audio and visual data and timestamps for the delivery of the data stream itself.

[0547] If subtitles are included in the stream, the subtitle decoder 3210 decodes the subtitles, synchronizes them with the video and audio frames, and supplies the video / audio / subtitle to the video / audio / subtitle display 3216.

[0548] The present invention is not limited to the system described above, and either the picture encoding device or the picture decoding device in the above embodiment can be incorporated into other systems, such as a vehicle system.

[0549] It should be noted that both the content supply system 3100 and the terminal device 3106 are configured to perform the methods shown in Figures 7 to 16 above.

[0550] Mathematical operators The mathematical operators used in this application are similar to those used in the C programming language. However, the results of integer division and arithmetic shift operations are more precisely defined, and further operators such as exponential calculations and real-valued division are defined. The numbering and counting rules generally start from 0, for example, "1st" is equivalent to the 0th, "2nd" is equivalent to the 1st, and so on.

[0551] Logical operators The following logical operators are defined as follows: [Table 10]

[0552] Logical operators The following logical operators are defined as follows: x&&y: Boolean "product" of x and y Boolean "union" of x||yx and y ! Boolean logic "negation" If x?y:zx is true or not equal to 0, it evaluates to the value of y; otherwise, it evaluates to the value of z.

[0553] Relational operators The following relational operators are defined as follows: > Larger than >= Above < Less than <= Below == equal != Not equal When a relational operator is applied to a syntax element or variable assigned the value "na" (not applicable), the value "na" is treated as a separate value of the syntax element or variable. The value "na" is considered not to be equal to any other value.

[0554] Bitwise operators The following bit operators are defined as follows. & Bitwise "product". When operating on integer arguments, it operates on the two's complement representation of the integer values. When operating on a binary argument that contains fewer bits than the other argument, the shorter argument is extended by adding higher bits equal to 0. | Bitwise "sum". When operating on integer arguments, it operates on the two's complement representation of the integer values. When operating on a binary argument that contains fewer bits than the other argument, the shorter argument is extended by adding higher bits equal to 0. ^ Bitwise "exclusive sum". When operating on integer arguments, it operates on the two's complement representation of the integer values. When operating on a binary argument that contains fewer bits than the other argument, the shorter argument is extended by adding higher bits equal to 0. x>>y Arithmetic right shift of the two's complement integer representation of x by y binary digits. This function is defined only for non-negative integer values of y. The bit shifted into the most significant bit (MSB) as a result of the right shift has a value equal to the MSB of x before the shift operation. x<<y Arithmetic left shift of the two's complement integer representation of x by y binary digits. This function is defined only for non-negative integer values of y. The bit shifted into the least significant bit (LSB) as a result of the left shift has a value equal to 0.

[0555] Assignment operators The following assignment operators are defined as follows. = Assignment operator ++ Increment. That is, x++ is equal to x=x+1. When used in an array index, it is evaluated to the value of the variable before the increment operation. -- Decrement. That is, x-- is equal to x=x-1. When used in an array index, it is evaluated to the value of the variable before the decrement operation. += Increment by the specified amount. That is, x += 3 is equivalent to x = x + 3, and x += (-3) is equivalent to x = x + (-3). -= Decrement by the specified amount. That is, x -= 3 is equivalent to x = x - 3, and x -= (-3) is equivalent to x = x - (-3).

[0556] Range notation The following notations are used to specify a range of values. x = y..z x takes integer values greater than or equal to y and less than or equal to z, where x, y, and z are integers and z is greater than y.

[0557] Mathematical functions The following mathematical functions are defined.

Number

Number

Number

Number

number

number

number

[0558] Order of operations When the precedence of an expression is not explicitly indicated by the use of parentheses, the following rules apply: - Higher-priority operations are evaluated before any lower-priority operations. - Operations with the same priority are evaluated sequentially from left to right.

[0559] The table below specifies the order of operations from highest to lowest, with higher positions in the table indicating higher priority.

[0560] For operators also used in the C programming language, the precedence used herein is the same as that used in the C programming language. [Table 11]

[0561] Text description of logical operations In text, the following format: if (condition 0) Statement 0 else(condition 1) Statement 1 ... else / *Reference notes regarding the remaining conditions* / statement n Statements of logical operations that are mathematically described may also be written in the following manner. ...as follows / ...the following applies: -If condition 0, statement 0 - If not, and condition 1 is true, then statement 1 -... -Otherwise (see note regarding the remaining conditions), statement n Each "if..., otherwise..., otherwise..." statement in the text is introduced by "if..." followed immediately by "...as follows" or "...as follows." The final condition in "if..., otherwise..., otherwise..." is always "otherwise...." Alternating "if..., otherwise..., otherwise..." statements can be identified by matching them with "...as follows" or "...as follows" ending with "otherwise...."

[0562] In text, the following format: if(condition 0a &&condition 0b) Statement 0 else if(condition 1a||condition 1b) Statement 1 ... else statement n Statements of logical operations that are mathematically described may also be written in the following manner. ...as follows / ...the following applies: -Statement 0: If all of the following conditions are true: -Condition 0a -condition 0b -Otherwise, if one or more of the following conditions are true, then statement 1: -Condition 1a -Condition 1b -… -Otherwise, statement n

[0563] In text, the following format: if (condition 0) Statement 0 if (condition 1) Statement 1 Statements of logical operations that are mathematically described may also be written in the following manner. When condition 0, statement 0 When condition 1 is met, statement 1

[0564] While embodiments of the present invention have been described primarily in terms of video coding, it should be noted that embodiments of the coding system 10, encoder 20, and decoder 30 (and correspondingly system 10), as well as other embodiments described herein, may also be configured for still image picture processing or coding, i.e., processing or coding of individual pictures independent of any preceding or consecutive pictures, as in video coding. Generally, when picture processing coding is limited to a single picture 17, only the interpretation units 244 (encoder) and 344 (decoder) may be available. All other functions (also called tools or techniques) of the video encoder 20 and video decoder 30 may be used equivalently for still image picture processing, such as residual calculation 204 / 304, transformation 206, quantization 208, inverse quantization 210 / 310, (inverse) transformation 212 / 312, partitioning 262 / 362, intra prediction 254 / 354, and / or loop filtering 220, 320, as well as entropy coding 270 and entropy decoding 304.

[0565] For example, embodiments of the encoder 20 and decoder 30, and the functions described herein with respect to the encoder 20 and decoder 30, may be implemented in hardware, software, firmware, or a combination thereof. If implemented in software, the functions may be stored as one or more instructions or codes on a computer-readable medium or transmitted over a communication medium and executed by a hardware-based processing unit. The computer-readable medium may include a computer-readable storage medium corresponding to a tangible medium such as a data storage medium, or a communication medium including, for example, any medium that facilitates the transfer of computer programs from one location to another according to a communication protocol. Thus, the computer-readable medium may generally correspond to (1) a non-transient tangible computer-readable storage medium, or (2) a communication medium such as a signal or carrier wave. The data storage medium may be any available medium accessible by one or more computers or one or more processors to retrieve instructions, codes and / or data structures for the implementation of the technology described herein. The computer program product may include a computer-readable medium.

[0566] Such computer-readable storage media may include, but are not limited to, computer-readable storage media, such as RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and is accessible by a computer. Any connection is also appropriately called a computer-readable medium. For example, if instructions are transmitted from a website, server or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of a medium. However, it should be understood that computer-readable storage media and data storage media do not include connections, carriers, signals, or other temporary media, but instead refer to non-temporary tangible storage media. When used herein, "disk" and "disc" include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy discs, and Blu-ray discs, where a "disk" typically reproduces data magnetically, and a "disc" reproduces data optically using a laser. Any combination of the above should also be included in the scope of computer-readable media.

[0567] Instructions may be executed by one or more processors, such as digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field-programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Therefore, when used herein, the term "processor" may refer to any of the above structures or any other structure suitable for the implementation of the technology described herein. Furthermore, in some embodiments, the functions described herein may be provided within dedicated hardware and / or software modules configured for encoding and decoding, or incorporated into a combined codec. The technology may also be fully implemented in one or more circuits or logic elements.

[0568] The technology of this disclosure may be implemented in a wide range of devices or apparatus, including wireless handsets, integrated circuits (ICs), or sets of ICs (e.g., chipsets). Various components, modules, or units are described in this disclosure to highlight the functional aspects of devices configured to perform the technology of this disclosure, but implementation by different hardware units is not necessarily required. Rather, as described above, various units may be coupled to a codec hardware unit in combination with appropriate software and / or firmware, or they may be provided by a collection of interoperable hardware units including one or more processors as described above.

Claims

1. A method for decoding a coded video bitstream, The steps include: obtaining a reference layer syntax element by parsing the coded video bitstream, wherein the value of the reference layer syntax element specifies whether the layer having index k is a direct reference layer of the layer having index i, and both i and k are integers and greater than or equal to 0; The step of determining whether the layer having index j is a reference layer of the layer having index i, based on the value of the reference layer syntax element, wherein the layer having index j is a reference layer of the layer having index k, and j is an integer and greater than or equal to 0. Steps include, if a condition is met, predicting the picture of the layer having index i based on the layer having index j, wherein the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, and the condition is that the layer having index j is a reference layer of the layer having index i. A method that includes this.

2. The method according to claim 1, wherein if the value of the reference layer syntax element specifies that the layer having index k is a direct reference layer of the layer having index i, then the layer having index j is a reference layer of the layer having index i.

3. A method for decoding a coded video bitstream, The steps include: obtaining a reference layer syntax element by parsing the coded video bitstream, wherein the value of the reference layer syntax element specifies whether the layer having index j is a direct reference layer of the layer having index i, and both i and j are integers and greater than or equal to 0; Steps include, if a condition is met, predicting the picture of the layer having index i based on the layer having index j, wherein the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, and the condition includes the value of the reference layer syntax element specifying that the layer having index j is a direct reference layer of the layer having index i. A method that includes this.

4. The method according to any one of claims 1 to 3, wherein the reference layer syntax element is a video parameter set (VPS) level syntax element, and the VPS is applied to the layer having index j and the layer having index i.

5. The method according to any one of claims 1 to 3, wherein the chroma format-related syntax element is a sequence parameter set (SPS) level syntax element, and the SPS is applied to the layer having index j or the layer having index i.

6. The method according to any one of claims 1 to 5, further comprising the step of parsing the coded video bitstream to obtain the chroma format-related syntax element applied to the layer having index i and the chroma format-related syntax element applied to the layer having index j, wherein the condition further includes that the value of the chroma format-related syntax element applied to the layer having index i is the same as the value of the chroma format-related syntax element applied to the layer having index j.

7. The method according to claim 1 or 2, further comprising the step of stopping decoding the coded video bitstream if the layer having index j is a reference layer of the layer having index i, and the value of the chroma format-related syntax element applied to the layer having index i is not the same as the value of the chroma format-related syntax element applied to the layer having index j.

8. The method according to claim 1 or 2, further comprising the step of predicting the picture of the layer having index i without using the layer having index j, if the layer having index j is not a reference layer of the layer having index i.

9. The method according to any one of claims 1 to 8, further comprising the step of determining that, if the conditions are met, the value of the chroma format-related syntax element applied to the layer having index i is the value of the chroma format-related syntax element applied to the layer having index j, without obtaining the chroma format-related syntax element applied to the layer having index i by parsing the coded video bitstream.

10. A method for decoding a coded video bitstream, The steps include: obtaining a reference layer syntax element by parsing the coded video bitstream, wherein the value of the reference layer syntax element specifies whether the layer having index k is a direct reference layer of the layer having index i, and both i and k are integers and greater than or equal to 0; The step of determining whether the layer having index j is a reference layer of the layer having index i, based on the value of the reference layer syntax element, wherein the layer having index j is a reference layer of the layer having index k, and j is an integer and greater than or equal to 0. Steps include, if a condition is met, predicting the picture of the layer having index i based on the layer having index j, wherein the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j, and the condition is that the layer having index j is a reference layer of the layer having index i. A method that includes this.

11. The method according to claim 10, wherein if the value of the reference layer syntax element specifies that the layer having index k is a direct reference layer of the layer having index i, then the layer having index j is a reference layer of the layer having index i.

12. A method for decoding a coded video bitstream, The steps include: obtaining a reference layer syntax element by parsing the coded video bitstream, wherein the value of the reference layer syntax element specifies whether the layer having index j is a direct reference layer of the layer having index i, and both i and j are integers and greater than or equal to 0; Steps include, if a condition is met, predicting the picture of the layer having index i based on the layer having index j, wherein the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j, and the condition includes the value of the reference layer syntax element specifying that the layer having index j is a direct reference layer of the layer having index i. A method that includes this.

13. The method according to any one of claims 10 to 12, wherein the reference layer syntax element is a video parameter set (VPS) level syntax element, and the VPS is applied to the layer having index j and the layer having index i.

14. The method according to any one of claims 10 to 12, wherein the bit depth-related syntax element is a sequence parameter set (SPS) level syntax element, and the SPS is applied to the layer having index j or the layer having index i.

15. The method according to any one of claims 10 to 14, further comprising the step of parsing the coded video bitstream to obtain the bit depth-related syntax element applied to the layer having index i and the bit depth-related syntax element applied to the layer having index j, wherein the condition is that the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j.

16. The method according to claim 10 or 11, further comprising the step of stopping decoding the coded video bitstream if the layer having index j is a reference layer of the layer having index i, and the value of the bit depth-related syntax element applied to the layer having index i is not the same as the value of the bit depth-related syntax element applied to the layer having index j.

17. The method according to claim 10 or 11, further comprising the step of predicting the picture of the layer having index i without using the layer having index j, if the layer having index j is not a reference layer of the layer having index i.

18. The method according to any one of claims 10 to 17, further comprising the step of determining that the value of the bit depth-related syntax element applied to the layer having index i is the value of the bit depth-related syntax element applied to the layer having index j, without obtaining the bit depth-related syntax element applied to the layer having index i by parsing the coded video bitstream.

19. The method according to any one of claims 10 to 18, wherein the bit depth-related syntax element specifies the bit depth of the luma and chroma samples of a picture in the layer to which the bit depth-related syntax element is applied.

20. A method for encoding video, The step of determining whether a layer having index j is a direct reference layer of a layer having index i, where both i and j are integers and greater than or equal to 0, and If the layer having index j is a direct reference layer of the layer having index i, the steps are to encode a reference layer syntax element having a value that specifies that the layer having index j is a direct reference layer of the layer having index i into the video bitstream, and to encode a chroma format related syntax element applied to the layer having index i and a chroma format related syntax element applied to the layer having index j into the video bitstream, wherein the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j. A method that includes this.

21. The method according to claim 20, further comprising the step of predicting the picture of the layer having index i based on the layer having index j, if the layer having index j is the direct reference layer of the layer having index i.

22. The method according to claim 20, further comprising the step of predicting the picture of the layer having index i without using the layer having index j, if the layer having index j is not a reference layer of the layer having index i.

23. A method for encoding video, The step of determining whether a layer having index j is a direct reference layer of a layer having index i, where both i and j are integers and greater than or equal to 0, and If the layer having index j is a direct reference layer of the layer having index i, the steps are to encode a reference layer syntax element having a value that specifies that the layer having index j is a direct reference layer of the layer having index i into the video bitstream, and to encode a bit depth-related syntax element applied to the layer having index i and a bit depth-related syntax element applied to the layer having index j into the video bitstream, wherein the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j. A method that includes this.

24. The method according to claim 23, further comprising the step of predicting the picture of the layer having index i based on the layer having index j, if the layer having index j is the direct reference layer of the layer having index i.

25. The method according to claim 23, further comprising the step of predicting the picture of the layer having index i without using the layer having index j, if the layer having index j is not a reference layer of the layer having index i.

26. The method according to any one of claims 23 to 25, wherein the bit depth-related syntax element specifies the bit depth of the luma and chroma samples of a picture in the layer to which the bit depth-related syntax element is applied.

27. A device for decoding a coded video bitstream, An acquisition unit configured to obtain a reference layer syntax element by parsing the coded video bitstream, wherein the value of the reference layer syntax element specifies whether the layer having index k is a direct reference layer of the layer having index i, and both i and k are integers and greater than or equal to 0. A decision unit configured to determine whether the layer having index j is a reference layer of the layer having index i, based on the value of the reference layer syntax element, wherein the layer having index j is a reference layer of the layer having index k, and j is an integer and greater than or equal to 0. A prediction unit configured to predict the picture of the layer having index i based on the layer having index j, provided that the conditions are met, wherein the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, and the conditions include the layer having index j being a reference layer of the layer having index i. A device that includes this.

28. The apparatus according to claim 17, wherein if the value of the reference layer syntax element specifies that the layer having index k is a direct reference layer of the layer having index i, then the layer having index j is a reference layer of the layer having index i.

29. A device for decoding a coded video bitstream, An acquisition unit configured to obtain a reference layer syntax element by parsing the coded video bitstream, wherein the value of the reference layer syntax element specifies whether the layer having index j is a direct reference layer of the layer having index i, and both i and j are integers and greater than or equal to 0. A prediction unit configured to predict a picture of a layer having index i based on a layer having index j, provided that a condition is met, wherein the value of a chroma format related syntax element applied to the layer having index i is the same as the value of a chroma format related syntax element applied to the layer having index j, and the condition includes the value of the reference layer syntax element specifying that the layer having index j is a direct reference layer of the layer having index i. A device that includes this.

30. The apparatus according to any one of claims 27 to 29, wherein the reference layer syntax element is a video parameter set (VPS) level syntax element, and the VPS is applied to the layer having index j and the layer having index i.

31. The apparatus according to any one of claims 27 to 29, wherein the chroma format-related syntax element is a sequence parameter set (SPS) level syntax element, and the SPS is applied to the layer having index j or the layer having index i.

32. The apparatus according to any one of claims 27 to 31, wherein the acquisition unit is further configured to acquire the chroma format-related syntax element applied to the layer having index i and the chroma format-related syntax element applied to the layer having index j by parsing the coded video bitstream, the condition further comprising that the value of the chroma format-related syntax element applied to the layer having index i is the same as the value of the chroma format-related syntax element applied to the layer having index j.

33. Further including a stopping unit, The apparatus according to claim 27 or 28, wherein the stop unit is configured to stop decoding the coded video bitstream if the layer having index j is a reference layer of the layer having index i, and the value of the chroma format-related syntax element applied to the layer having index i is not the same as the value of the chroma format-related syntax element applied to the layer having index j.

34. The apparatus according to claim 27 or 28, wherein the acquisition unit is further configured to predict the picture of the layer having index i without using the layer having index j if the layer having index j is not a reference layer of the layer having index i.

35. The apparatus according to any one of claims 27 to 34, wherein the determination unit is further configured to determine, when the condition is met, that the value of the chroma format-related syntax element applied to the layer having index i is the value of the chroma format-related syntax element applied to the layer having index j, without obtaining the chroma format-related syntax element applied to the layer having index i by parsing the coded video bitstream.

36. A device for decoding a coded video bitstream, An acquisition unit configured to obtain a reference layer syntax element by parsing the coded video bitstream, wherein the value of the reference layer syntax element specifies whether the layer having index k is a direct reference layer of the layer having index i, and both i and k are integers and greater than or equal to 0. A decision unit configured to determine whether the layer having index j is a reference layer of the layer having index i, based on the value of the reference layer syntax element, wherein the layer having index j is a reference layer of the layer having index k, and j is an integer and greater than or equal to 0. A prediction unit configured to predict a picture of a layer having index i based on a layer having index j, provided that a condition is met, wherein the value of a bit depth-related syntax element applied to the layer having index i is the same as the value of a bit depth-related syntax element applied to the layer having index j, and the condition includes the layer having index j being a reference layer of the layer having index i. A device that includes this.

37. The apparatus according to claim 36, wherein if the value of the reference layer syntax element specifies that the layer having index k is a direct reference layer of the layer having index i, then the layer having index j is a reference layer of the layer having index i.

38. A device for decoding a coded video bitstream, An acquisition unit configured to obtain a reference layer syntax element by parsing the coded video bitstream, wherein the value of the reference layer syntax element specifies whether the layer having index j is a direct reference layer of the layer having index i, and both i and j are integers and greater than or equal to 0. A prediction unit configured to predict a picture of a layer having index i based on a layer having index j, provided that a condition is met, wherein the value of a bit depth-related syntax element applied to the layer having index i is the same as the value of a bit depth-related syntax element applied to the layer having index j, and the condition includes the value of the reference layer syntax element specifying that the layer having index j is a direct reference layer of the layer having index i. A device that includes this.

39. The apparatus according to any one of claims 36 to 38, wherein the reference layer syntax element is a video parameter set (VPS) level syntax element, and the VPS is applied to the layer having index j and the layer having index i.

40. The apparatus according to any one of claims 36 to 38, wherein the bit depth-related syntax element is a sequence parameter set (SPS) level syntax element, and the SPS is applied to the layer having index j or the layer having index i.

41. The apparatus according to any one of claims 36 to 40, wherein the acquisition unit is further configured to acquire the bit depth-related syntax element applied to the layer having index i and the bit depth-related syntax element applied to the layer having index j by parsing the coded video bitstream, the condition further comprising that the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j.

42. Further including a stopping unit, The apparatus according to claim 36 or 37, wherein the stop unit is configured to stop decoding the coded video bitstream if the layer having index j is a reference layer of the layer having index i, and the value of the bit depth-related syntax element applied to the layer having index i is not the same as the value of the bit depth-related syntax element applied to the layer having index j.

43. The apparatus according to claim 36 or 37, wherein the prediction unit is further configured to predict the picture of the layer having index i without using the layer having index j if the layer having index j is not a reference layer of the layer having index i.

44. The apparatus according to any one of claims 36 to 43, wherein the determination unit is further configured to determine that the value of the bit depth-related syntax element applied to the layer having index i is the value of the bit depth-related syntax element applied to the layer having index j, without obtaining the bit depth-related syntax element applied to the layer having index i by parsing the coded video bitstream.

45. The apparatus according to any one of claims 36 to 44, wherein the bit depth-related syntax element specifies the bit depth of the luma and chroma samples of a picture in the layer to which the bit depth-related syntax element is applied.

46. A device for encoding video, A decision unit configured to determine whether a layer having index j is a direct reference layer of a layer having index i, wherein both i and j are integers and greater than or equal to 0, An encoding unit configured to encode a reference layer syntax element having a value specifying that the layer having index j is a direct reference layer of the layer having index i into a video bitstream, and to encode a chroma format related syntax element applied to the layer having index i and a chroma format related syntax element applied to the layer having index j into the video bitstream, wherein the value of the chroma format related syntax element applied to the layer having index i is the same as the value of the chroma format related syntax element applied to the layer having index j, and A device that includes this.

47. Further including the first prediction unit, The apparatus according to claim 46, wherein the first prediction unit is configured to predict a picture of the layer having index i based on the layer having index j, when the layer having index j is the direct reference layer of the layer having index i.

48. Further including a second prediction unit, The apparatus according to claim 46, wherein the first prediction unit is configured to predict the picture of the layer having index i without using the layer having index j if the layer having index j is not a reference layer of the layer having index i.

49. A device for encoding video, A decision unit configured to determine whether a layer having index j is a direct reference layer of a layer having index i, wherein both i and j are integers and greater than or equal to 0, An encoding unit configured to encode a reference layer syntax element having a value specifying that the layer having index j is a direct reference layer of the layer having index i into a video bitstream, and to encode a bit depth-related syntax element applied to the layer having index i and a bit depth-related syntax element applied to the layer having index j into the video bitstream, wherein the value of the bit depth-related syntax element applied to the layer having index i is the same as the value of the bit depth-related syntax element applied to the layer having index j, and A device that includes this.

50. Further including the first prediction unit, The apparatus according to claim 49, wherein the first prediction unit is configured to predict a picture of the layer having index i based on the layer having index j, when the layer having index j is the direct reference layer of the layer having index i.

51. Further including a second prediction unit, The apparatus according to claim 49, wherein the second prediction unit is configured to predict the picture of the layer having index i without using the layer having index j if the layer having index j is not a reference layer of the layer having index i.

52. The apparatus according to any one of claims 49 to 51, wherein the bit depth-related syntax element specifies the bit depth of the luma and chroma samples of a picture in the layer to which the bit depth-related syntax element is applied.

53. An encoder comprising a processing circuit for performing the method according to any one of claims 20 to 26.

54. A decoder including a processing circuit for performing the method according to any one of claims 1 to 19.

55. A computer program product comprising program code for performing the method described in any one of claims 1 to 26 when executed on a computer or processor.

56. One or more processors, A non-temporary computer-readable storage medium coupled to one or more processors and storing a program for execution by the processors. A decoder that includes, A decoder wherein, when the programming is executed by the processor, the decoder is configured to perform the method described in any one of claims 1 to 19.

57. One or more processors, A non-temporary computer-readable storage medium coupled to the processor and storing a program for execution by the processor. An encoder that includes, An encoder wherein, when the programming is executed by the processor, the encoder is configured to perform the method according to any one of claims 20 to 26.

58. A non-temporary computer-readable medium that, when executed by a computer device, carries program code that causes the computer device to execute the method according to any one of claims 1 to 26.

59. A non-temporary storage medium containing an encoded bitstream that is decoded by an image decoding device, A non-temporary storage medium wherein the bitstream includes encoded data of at least one layer, the bitstream further includes a chroma format-related syntax element of a layer having index i and a chroma format-related syntax element of a layer having index j, and when the layer having index j is a reference layer of the layer having index i, the value of the chroma format-related syntax element of the layer having index i is the same as the value of the chroma format-related syntax element of the layer having index j, and both i and j are integers and greater than or equal to 0.

60. A non-temporary storage medium containing an encoded bitstream that is decoded by an image decoding device, A non-temporary storage medium wherein the bitstream includes encoded data of at least one layer, the bitstream further includes a bit depth-related syntax element of a layer having index i and a bit depth-related syntax element of a layer having index j, and when the layer having index j is a reference layer of the layer having index i, the value of the bit depth-related syntax element of the layer having index i is the same as the value of the bit depth-related syntax element of the layer having index j, and both i and j are integers and greater than or equal to 0.

61. The non-temporary storage medium according to claim 60, wherein the bit depth-related syntax element specifies the bit depth of the luma and chroma samples of a picture in the layer to which the bit depth-related syntax element is applied.

62. The non-temporary storage medium according to any one of claims 59 to 61, wherein the bitstream further includes a reference layer syntax element, the value of the reference layer syntax element specifies that the layer having index j is a reference layer of the layer having index i, or that the layer having index j is a direct reference layer of the layer having index i.

Images