Encoders, decoders, and corresponding methods

Abstract

A method of decoding a video or picture bitstream implemented by a decoding device, the bitstream including data representing a current video coding layer, the method including, if it is determined that the current video coding layer is the only layer in the bitstream, using an identifier of a NAL unit of the current video coding layer as an identifier of the current video coding layer.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims priority to International Patent Application PCT / EP2020 / 057229, filed March 17, 2020. The disclosure of the aforementioned patent application is incorporated herein by reference in its entirety.

[0002] TECHNICAL FIELD Embodiments of the present application relate generally to the field of picture processing, and more specifically to video coding. [Background technology]

[0003] Video coding (video encoding and decoding) is used in a wide range of digital video applications, such as, for example, digital television broadcasting, video transmission over the Internet and mobile networks, real-time interactive applications such as video chat, video conferencing, DVDs and Blu-ray® discs, video content acquisition and editing systems, and camcorders in security applications. Summary of the Invention [Problem to be solved by the invention]

[0004] The amount of video data required to render even a relatively short video can be substantial, which can pose difficulties when streaming or otherwise communicating the data over communication networks that have limited bandwidth capacity. Thus, video data is typically compressed before being communicated over modern telecommunications networks. The size of the video can also be an issue when storing the video on a storage device, since memory resources may be limited. Video compression devices often use software and / or hardware at the source to code the video data before transmission or storage, thereby reducing the amount of data required to represent a digital video image. The compressed data is then received at the destination by a video decompression device that decodes the video data. With limited network resources and an ever-increasing demand for higher video quality, improved compression and decompression techniques are desired that improve compression ratios with little or no sacrifice in picture quality. [Means for solving the problem]

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

[0006] These and other objects are achieved by the subject matter of the independent claims. Further embodiments are evident from the dependent claims, the description and the drawings.

[0007] According to a first aspect, the present invention relates to a method for decoding a video or picture bitstream implemented by a decoding device, the bitstream comprising data representing a current video coding layer, the method comprising the steps of determining whether the current video coding layer is the only layer in the bitstream, and if it is determined (e.g. determined only if) that the current video coding layer is the only layer in the bitstream (e.g. sps_video_parameter_set_id is equal to 0), using an identifier of a NAL unit of the current video coding layer (e.g. nuh_layer_id) as an identifier of the current video coding layer (e.g. vps_layer_id).

[0008] The VPS is an arbitrary parameter set. For example, in the case of a single-layer bitstream, there may be no VPS in the bitstream, and therefore the identifier of the current video coding layer that may be present in the VPS may not be present in the bitstream, and using the identifier of the NAL unit of the current video coding layer as the identifier of the current video coding layer of the single-layer bitstream ensures the implementation of the video coding.

[0009] According to an implementation, the method may further include predicting a current slice of the current video coding layer using the identifier of the current video coding layer.

[0010] According to one implementation, the method may further include, if it is determined that the bitstream includes multiple layers (e.g., sps_video_parameter_set_id is greater than 0), obtaining an identifier of the current video coding layer by parsing the bitstream.

[0011] The so provided method of decoding a video bitstream ensures efficient signaling of the identifier of the current video coding layer and saves bitrate.

[0012] According to one implementation, the identifier of the current video coding layer may be used to construct one or more reference picture lists for the current slice of the current video coding layer, and predicting the current slice of the current video coding layer using the identifier of the current video coding layer may include predicting the current slice using the one or more reference picture lists.

[0013] According to one implementation, the NAL unit of the current video coding layer may be a VCL NAL unit of the current video coding layer present in the bitstream.

[0014] When a single-layer bitstream is obtained from a sub-bitstream extraction, it is more accurate to use the identifier of the VCL NAL unit of the current video coding layer as the identifier of the current video coding layer of the single-layer bitstream, because the non-VCL units in the single-layer bitstream may have different layer identifiers.

[0015] According to an implementation, the VCL NAL unit of the current video coding layer may be any one VCL NAL unit (or all VCL NAL units) of the current video coding layer present in the bitstream.

[0016] According to a second aspect, the present invention relates to a method for encoding a video or picture bitstream implemented by an encoding device, the bitstream comprising data representing a current video coding layer, the method comprising the steps of determining whether the current video coding layer is the only layer in the bitstream and, if it is determined that the current video coding layer is the only layer in the bitstream, using an identifier of a NAL unit of the current video coding layer as an identifier of the current video coding layer.

[0017] According to an implementation, the method may further include predicting a current slice of the current video coding layer using the identifier of the current video coding layer.

[0018] According to one implementation, the method may further include, if it is determined that the bitstream includes multiple layers (eg, sps_video_parameter_set_id is greater than 0), encoding an identifier of the current video coding layer into the bitstream.

[0019] According to one implementation, the identifier of the current video coding layer may be used to construct one or more reference picture lists for the current slice of the current video coding layer, and predicting the current slice of the current video coding layer using the identifier of the current video coding layer may include predicting the current slice using the one or more reference picture lists.

[0020] According to one implementation, the NAL unit of the current video coding layer may be a VCL NAL unit of the current video coding layer present in the bitstream.

[0021] According to an implementation, the VCL NAL unit of the current video coding layer may be any one VCL NAL unit (or all VCL NAL units) of the current video coding layer present in the bitstream.

[0022] According to a third aspect, the present invention relates to an apparatus for decoding a (coded) video bitstream, the apparatus comprising: a determination unit configured to determine whether a current video coding layer is the only layer in the bitstream; and a prediction unit configured to use an identifier of a NAL unit of the current video coding layer (e.g., nuh_layer_id) as an identifier of the current video coding layer (e.g., vps_layer_id) if it is determined (e.g., determined only if) that the current video coding layer is the only layer in the bitstream (e.g., sps_video_parameter_set_id is equal to 0).

[0023] According to an implementation, the prediction unit may be further configured to predict a current slice of the current video coding layer using the identifier of the current video coding layer.

[0024] According to one implementation, if it is determined that the bitstream includes multiple layers (e.g., sps_video_parameter_set_id is greater than 0), the device may further include an acquisition unit configured to acquire an identifier of the current video coding layer by parsing the bitstream.

[0025] According to an implementation, the identifier of the current video coding layer may be used to construct one or more reference picture lists for a current slice of the current video coding layer, and the prediction unit is configured to predict the current slice of the current video coding layer using the identifier of the current video coding layer and predict the current slice using the one or more reference picture lists. It can be configured as follows: .

[0026] According to one implementation, the NAL unit of the current video coding layer may be a VCL NAL unit of the current video coding layer present in the bitstream.

[0027] According to an implementation, the VCL NAL unit of the current video coding layer may be any one VCL NAL unit (or all VCL NAL units) of the current video coding layer present in the bitstream.

[0028] According to a fourth aspect of the present invention, the present invention relates to an apparatus for encoding a video bitstream, the apparatus comprising: a determination unit configured to determine whether a current video coding layer is the only layer in the bitstream; and a prediction unit configured to use an identifier of a NAL unit of the current video coding layer as an identifier of the current video coding layer if it is determined that the current video coding layer is the only layer in the bitstream.

[0029] According to an implementation, the prediction unit may be further configured to predict a current slice of the current video coding layer using the identifier of the current video coding layer.

[0030] According to one implementation, if it is determined that the bitstream includes multiple layers (e.g., sps_video_parameter_set_id is greater than 0), the device may further include an encoding unit configured to encode an identifier of the current video coding layer into the bitstream.

[0031] According to an implementation form, an identifier of the current video coding layer may be used to construct one or more reference picture lists for a current slice of the current video coding layer, and a prediction unit may be configured to predict the current slice of the current video coding layer using the identifier of the current video coding layer and may also be configured to predict the current slice using the one or more reference picture lists.

[0032] According to one implementation, the NAL unit of the current video coding layer is a VCL NAL unit of the current video coding layer present in the bitstream.

[0033] According to one implementation, a VCL NAL unit of the current video coding layer is any one VCL NAL unit (or all VCL NAL units) of the current video coding layer that are present in the bitstream.

[0034] The method according to the first aspect of the invention may be performed by an apparatus according to the third aspect of the invention. Further features and implementations of the apparatus according to the third aspect of the invention correspond to the features and implementations of the method according to the first aspect of the invention.

[0035] The method according to the second aspect of the invention may be performed by an apparatus according to the fourth aspect of the invention. Further features and implementations of the apparatus according to the fourth aspect of the invention correspond to the features and implementations of the method according to the second aspect of the invention.

[0036] The above methods may be implemented in a decoding device or an encoding device, respectively, and thus an encoder is provided that includes a processing circuit for performing a method for encoding a video bitstream according to any one of the above examples. Further, an encoder is provided that includes one or more processors and a non-transitory computer-readable storage medium coupled to the processors and storing programming for execution by the processors, the programming, when executed by the processors, configures the encoder to perform a method for encoding a video bitstream according to any one of the above examples. Similarly, a decoder is provided that includes a processing circuit for performing a method for decoding a video bitstream according to any one of the above examples, and a decoder is provided that includes one or more processors and a non-transitory computer-readable storage medium coupled to the processors and storing programming for execution by the processors, the programming, when executed by the processors, configures the decoder to perform a method for decoding a video bitstream according to any one of the above examples.

[0037] Further provided is a computer program product including program code for performing a method according to any one of the above examples when executed on a computer or processor. Similarly, provided is a non-transitory computer readable medium carrying program code that, when executed by a computing device, causes the computing device to perform a method according to any one of the above examples.

[0038] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will become apparent from the description, drawings, and claims.

[0039] In the following, embodiments of the invention are explained in more detail with reference to the accompanying figures and drawings. [Brief description of the drawings]

[0040] [Figure 1A] 1 is a block diagram illustrating an example of a video coding system configured to implement embodiments of the present invention. [Figure 1B] 2 is a block diagram illustrating another example of a video coding system configured to implement embodiments of the present invention. [Diagram 2] FIG. 2 is a block diagram illustrating an example of a video encoder configured to implement embodiments of the present invention. [Diagram 3] 2 is a block diagram illustrating an exemplary structure of a video decoder configured to implement embodiments of the present invention. [Figure 4] 1 is a block diagram showing an example of an encoding device or a decoding device. [Diagram 5] 11 is a block diagram showing another example of an encoding device or a decoding device. [Figure 6] FIG. 13 is a diagram illustrating an example of a raster scan order. [Figure 7] A diagram showing examples of tiles, slices, and subpictures. [Figure 8] FIG. 2 illustrates an example of layers and sub-layers for scalable video coding. [Figure 9] FIG. 2 illustrates a method for decoding a video bitstream according to one embodiment. [Figure 10] FIG. 2 illustrates a method for encoding a video bitstream according to one embodiment. [Figure 11] FIG. 2 illustrates a method for decoding a video bitstream according to one embodiment. [Figure 12] FIG. 2 illustrates a method for encoding a video bitstream according to one embodiment. [Figure 13] 31 is a block diagram showing an exemplary structure of a content delivery system 3100 for implementing a content distribution service. [Figure 14] FIG. 2 is a block diagram illustrating the structure of an example of a terminal device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] In the following description, reference is made to the accompanying drawings which form a part of this disclosure and which show, by way of example, certain aspects of the embodiments of the invention or in which the embodiments of the invention may be used. It is understood that the embodiments of the invention may be used in other ways and include structural or logical changes not shown in the drawings. Therefore, the following detailed description should not be taken in a limiting sense, and the scope of the invention is defined by the appended claims.

[0042] For example, it is understood that disclosure related to a described method also applies to a corresponding device or system configured to perform the method, and vice versa. For example, when one or more particular method steps are described, the corresponding device may include one or more units (e.g., one unit performing one or more steps, or multiple units each performing one or more of the multiple steps), e.g., functional units, to perform the described one or more method steps, even if such one or more units are not explicitly described or illustrated. On the other hand, when, for example, a particular apparatus is described based on one or more units, e.g., functional units, the corresponding method may include one step (e.g., one step performing the function of one or more units, or multiple steps each performing one or more functions of multiple units) to perform the function of one or more units, even if such one or more steps are not explicitly described or illustrated. Furthermore, it is to be understood that features of various exemplary embodiments and / or aspects described herein may be combined with each other, unless otherwise specified.

[0043] Video coding typically refers to the processing of a sequence of pictures forming a video or a 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) includes two parts: video encoding and video decoding. Video encoding is performed on the source side and typically involves processing of 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 process of the encoder to reconstruct the video picture. The embodiments referring to "coding" of a video picture (or pictures in general) should be understood to relate to "encoding" or "decoding" of the video picture or the respective video sequence. The combination of the encoding and decoding parts is also called CODEC (Coding and Decoding).

[0044] In the case of lossless video coding, the original video picture can be reconstructed, i.e. the reconstructed video picture is of the same quality as the original video picture (assuming there is no transmission loss or other data loss during storage or transmission). In the case of lossy video coding, further compression, e.g. by quantization, is performed to reduce the amount of data representing the video picture, which cannot be completely reconstructed at the decoder, i.e. the quality of the reconstructed video picture is low or inferior compared to the quality of the original video picture.

[0045] Some video coding standards belong to the group of "lossy hybrid video codecs" (i.e., they combine spatial and temporal prediction in the sample domain and perform 2D transform coding to apply quantization in the transform domain). Each picture of a video sequence is usually partitioned into a set of non-overlapping blocks, and coding is usually performed at the block level. In other words, in the encoder, a video is usually processed, i.e., encoded, at the block (video block) level, for example, by using spatial (intra-picture) and / or temporal (inter-picture) prediction to generate a prediction block, subtracting the prediction block from a current block (the block currently being / to be processed) to obtain a residual block, and transforming and quantizing the residual block in the transform domain to reduce (compress) the amount of data to be transmitted, while in the decoder, the inverse process is applied to the encoded or compressed block to reconstruct the current block for representation. Furthermore, the encoder replicates the processing loop of the decoder so that both generate the same prediction (e.g., intra-prediction and inter-prediction) and / or processing of subsequent blocks, i.e., reconstruction for coding.

[0046] In the following embodiment of a video coding system 10, a video encoder 20 and a video decoder 30 are described based on FIGS. 1 to 3. FIG.

[0047] 1A is a schematic block diagram illustrating an example coding system 10 that may utilize techniques of the present application, such as video coding system 10 (or short coding system 10). A video encoder 20 (or short encoder 20) and a video decoder 30 (or short decoder 30) of video coding system 10 represent examples of devices that may be configured to perform techniques according to various examples described in the present application.

[0048] As shown in FIG. 1A, coding system 10 may generate encoded picture data 21, e.g., encoded picture data 21 The present invention includes a source device 12 configured to provide a destination device 14 with a digital signal for decoding.

[0049] The source device 12 includes an encoder 20 , and may additionally, i.e. optionally, include a picture source 16 , a pre-processor (or pre-processing unit) 18 , for example a picture pre-processor 18 , and a communication interface or unit 22 .

[0050] Picture source 16 may include or be any kind of picture capture device, e.g., a camera for capturing real-world pictures, and / or any kind of picture generation device, e.g., a computer graphics processor for generating computer-animated pictures, or any kind of other device for obtaining / 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). Picture source may be any kind of memory or storage that stores any of the aforementioned pictures.

[0051] In distinction from the pre-processor 18 and the processing performed by the pre-processing unit 18 , the picture or picture data 17 may also be referred to as a raw picture or raw picture data 17 .

[0052] The pre-processor 18 is configured to receive the (raw) picture data 17 and perform pre-processing on the picture data 17 to obtain a pre-processed picture 19 or pre-processed picture data 19. The pre-processing performed by the pre-processor 18 may include, for example, cropping, color format conversion (e.g., from RGB to YCbCr), color correction, or noise removal. It should be understood that the pre-processing unit 18 may be an optional component.

[0053] Video encoder 20 is configured to receive pre-processed picture data 19 and to provide encoded picture data 21 (further details are described below, eg, with reference to FIG. 2).

[0054] The communications interface 22 of the source device 12 may be configured to receive the encoded picture data 21 and transmit the encoded picture data 21 (or a further processed version thereof) via the communications channel 13 to another device, such as the destination device 14 or any other device for storage or direct reconstruction.

[0055] The destination device 14 includes a decoder 30 (eg, a video decoder 30), and may further, i.e. optionally, include a communications interface or unit 28, a post-processor 32 (or a post-processing unit 32), and a display device 34.

[0056] The communications interface 28 of the destination device 14 is configured to receive the encoded picture data 21 (or a further processed version thereof), 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 a decoder 30.

[0057] Communications interface 22 and communications interface 28 may communicate encoded picture data 21 or encoded data 22 over a direct communications link between source device 12 and destination device 14, e.g., a direct wired or wireless connection, or over any type of network, e.g., a wired or wireless network, or any combination thereof, or any type of private and public network, or any combination thereof. Ta It may be configured to transmit or receive.

[0058] The communications interface 22 may be configured, for example, to package the encoded picture data 21 in an appropriate format, e.g., into packets, and / or to process the encoded picture data using any type of transmission encoding or processing for transmission over a communications link or network.

[0059] Communications interface 28, which forms a counterpart of communications interface 22, may be configured, for example, to receive transmitted data and process the transmitted data using any kind of corresponding transmission decoding or processing and / or depackaging to obtain encoded picture data 21.

[0060] Both communication interface 22 and communication interface 28 may be configured as unidirectional communication interfaces, as indicated by the arrow of communication channel 13 in FIG. 1A pointing from source device 12 to destination device 14, or as bidirectional communication interfaces, and may be configured, e.g., to set up a connection, e.g., to send and receive messages, to confirm and exchange a communication link and / or any other information related to a data transmission, e.g., an encoded picture data transmission.

[0061] The decoder 30 is configured to receive the encoded picture data 21 and to provide decoded picture data 31 or a decoded picture 31 (further details are described below, for example, based on FIG. 3 or FIG. 5).

[0062] The post-processor 32 of the destination device 14 is configured to post-process the decoded picture data 31 (also referred to as reconstructed picture data), e.g., the decoded picture 31, to obtain post-processed picture data 33, e.g., the post-processed picture 33. The post-processing performed by the post-processing unit 32 may include, for example, color format conversion (e.g., from YCbCr to RGB), color correction, cropping or resampling, or any other processing to prepare the decoded picture data 31, for example, for display by a display device 34.

[0063] A display device 34 of destination device 14 is configured to receive the post-processed picture data 33, for example for displaying the picture to a user or viewer. The display device 34 may be or include any type of display for presenting the reconstructed picture, for example, an internal or external display or monitor. The display may include, for example, a liquid crystal display (LCD), an organic light emitting diode (OLED) display, a plasma display, a projector, a micro LED display, liquid crystal on silicon (LCoS), a digital light processor (DLP), or any type of other display.

[0064] 1A illustrates source device 12 and destination device 14 as separate devices, an embodiment of the devices may also include both source device 12 or corresponding functionality, and destination device 14 or corresponding functionality, or both. In such an embodiment, source device 12 or corresponding functionality, and destination device 14 or corresponding functionality may be implemented using the same hardware and / or software, or by separate hardware and / or software, or any combination thereof.

[0065] As will be apparent to those skilled in the art based on this description, the presence and (exact) split of different units or functions within source device 12 and / or destination device 14 as shown in FIG. 1A may vary depending on the actual device and application.

[0066] 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 circuitry shown in FIG. 1B, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), discrete logic, hardware, dedicated to video coding, or any combination thereof. The encoder 20 may be implemented via processing circuitry 46 to embody various modules described with respect to the encoder 20 of FIG. 2 and / or any other encoder system or subsystem described herein. The decoder 30 may be implemented via processing circuitry 46 to embody various modules described with respect to the decoder 30 of FIG. 3 and / or any other decoder system or subsystem described herein. The processing circuitry may be configured to perform various operations, as described below. As shown in FIG. 5, if the techniques are implemented partially in software, the device may store instructions of the software in a suitable non-transitory computer-readable storage medium and execute the instructions in hardware using one or more processors to perform the techniques of this disclosure. Either video encoder 20 and video decoder 30 may be integrated as part of a combined encoder / decoder (CODEC) in a single device, for example, as shown in FIG. 1B.

[0067] Source device 12 and destination device 14 may include any of a wide range of devices, including any type of handheld or fixed device, such as a notebook or laptop computer, a mobile phone, a smartphone, a tablet or tablet computer, a camera, a desktop computer, a set-top box, a television, a display device, a digital media player, a video game console, a video streaming device (such as a content service server or a content delivery server), a broadcast receiving device, a broadcast transmitter device, and the like, and may use no operating system at all or any type of operating system. In some cases, source device 12 and destination device 14 may be equipped for wireless communication. Thus, source device 12 and destination device 14 may be wireless communication devices.

[0068] In some cases, the video coding system 10 shown in FIG. 1A is merely an example, and techniques of the present application may apply to video coding settings (e.g., video encoding or video decoding) that do not necessarily include data communication between an encoding device and a decoding device. In other examples, data may be retrieved from a local memory, streamed over a network, etc. A video encoding device may encode and store data in a memory, and / or a video decoding device may retrieve and decode data from a memory. In some examples, encoding and decoding are performed by devices that do not communicate with each other, but simply encode data in a memory and / or retrieve data from a memory and decode it.

[0069] For convenience of explanation, embodiments of the present invention are described herein by reference to reference software of, for example, High-Efficiency Video Coding (HEVC) or Versatile Video coding (VVC), a next-generation video coding standard developed by the Joint Collaboration Team on Video Coding (JCT-VC) of the ITU-T Video Coding Experts Group (VCEG) and the ISO / IEC Motion Picture Experts Group (MPEG). Those skilled in the art will appreciate that embodiments of the present invention are not limited to HEVC or VVC.

[0070] Encoders and encoding methods FIG. 2 shows a schematic block diagram of an exemplary video encoder 20 configured to implement the techniques of the present application. In the example of FIG. 2, the video encoder 20 includes an input 201 (or an input interface 201), a residual calculation unit 204, a transform processing unit 206, a quantization unit 208, an inverse quantization unit 210, and an inverse transform 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 encoding unit 270, and an output 272 (or an output interface 272). The mode selection unit 260 may include an inter prediction unit 244, an intra prediction unit 254, and a partitioning unit 262. The inter prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown). The video encoder 20 shown in FIG. 2 may also be referred to as a hybrid video encoder or a video encoder with a hybrid video codec.

[0071] The residual calculation unit 204, the transform processing unit 206, the quantization unit 208, and the mode selection unit 260 may be said to form a forward signal path of the encoder 20, while the inverse quantization unit 210, the inverse transform 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 be said to form a backward signal path of the video encoder 20, which corresponds to the signal path of the decoder (see the video decoder 30 of FIG. 3). The inverse quantization unit 210, the inverse transform 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 may also be said to form a “built-in decoder” of the video encoder 20.

[0072] Pictures and picture partitioning (pictures and blocks) The encoder 20 may be configured to receive, via an input 201, a picture 17 (or picture data 17), e.g. a picture of a sequence of pictures forming a video or a video sequence. The received picture or picture data may also be a preprocessed picture 19 (or preprocessed picture data 19). For simplicity, the following description refers to the picture 17. The picture 17 may also be called the current picture or the picture to be coded (particularly in video coding, to distinguish the current picture from other pictures, e.g. previously encoded and / or decoded pictures of the same video sequence, i.e. a video sequence that also includes the current picture).

[0073] A (digital) picture is or can be considered as a two-dimensional array or matrix of samples with intensity values. A sample in the array may also be called a pixel (short for picture element) or a 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, three color components are usually used, i.e. a picture may be represented by or may contain three sample arrays. In an RBG format or color space, a picture contains corresponding red, green and blue sample arrays. However, in video coding, each pixel is usually represented in a luminance and chrominance format or color space, e.g. YCbCr, which contains a luminance component denoted by Y (sometimes L is used instead) and two chrominance components denoted by Cb and Cr. The luminance (or short luma) component Y represents the brightness or intensity of the gray level (e.g., as in a grayscale picture), and the two chrominance (or short chroma) components Cb and Cr represent the chromaticity or color information components. Thus, a picture in YCbCr format contains 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 or transformed into YCbCr format and vice versa, a process also known as color conversion or transformation. If the picture is monochrome, the picture may contain only a luminance sample array. Thus, a picture may be, for example, an array of luminance samples in monochrome format, or an array of luminance samples and two corresponding arrays of chroma samples in 4:2:0, 4:2:2, and 4:4:4 color formats.

[0074] An embodiment of video encoder 20 may include a picture partitioning unit (not shown in FIG. 2) configured to partition picture 17 into multiple (usually non-overlapping) picture blocks 203. These blocks may also be called root blocks, macroblocks (H.264 / AVC), or coding tree blocks (CTBs), or coding tree units (CTUs) (H.265 / HEVC and VVC). The picture partitioning unit may be configured to use the same block size for all pictures of a video sequence and a corresponding grid that defines the block size, or to vary the block size among pictures or subsets of pictures or groups of pictures, and to partition each picture into corresponding blocks.

[0075] In further embodiments, the video encoder may be configured to directly receive block 203 of picture 17, e.g., one, more than one, or all of the blocks that form picture 17. Picture block 203 may also be referred to as a current picture block or a picture block to be coded.

[0076] Similar to the picture 17, the picture block 203 is also a two-dimensional array or matrix of samples having intensity values ​​(sample values), but with smaller dimensions than the picture 17, or can be considered as such. In other words, the block 203 may include, for example, one sample array (e.g., a luma array in case of a monochrome picture 17, or a luma or chroma array in case of a color picture) or three sample arrays (e.g., one luma array and two chroma arrays in case of a color picture 17), or any other number and / or type of arrays depending on the color format applied. The number of samples in the horizontal and vertical directions (or axes) of the block 203 defines the size of the 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 transform coefficients.

[0077] The embodiment of video encoder 20 shown in FIG. 2 may be configured to encode picture 17 block-by-block, eg, encoding and prediction is performed for each block 203.

[0078] The embodiment of video encoder 20 shown in FIG. 2 may be further configured to partition and / or encode pictures by using slices (also referred to as video slices), where a picture may be partitioned or encoded using one or more slices (typically non-overlapping), each of which may include one or more blocks (e.g., CTUs).

[0079] The embodiment of video encoder 20 shown in FIG. 2 may be further configured to partition and / or encode a picture by using tile groups (also referred to as video tile groups) and / or tiles (also referred to as video tiles), where a picture may be partitioned or encoded using one or more tile groups (typically non-overlapping), each tile group may include, for example, one or more blocks (e.g., CTUs) or one or more tiles, and each tile may be, for example, rectangular and may include one or more blocks (e.g., CTUs), and may be, for example, a full block or a partial block.

[0080] Residual calculation The residual calculation unit 204 may be configured to calculate the residual block 205 (also referred to as residual 205) based on the picture block 203 and the prediction block 265, for example, by subtracting sample values ​​of the prediction block 265 from sample values ​​of the picture block 203 on a sample-by-sample (pixel-by-pixel) basis to obtain the residual block 205 in the sample domain (further details about the prediction block 265 are provided later).

[0081] conversion The transform processing unit 206 may be configured to apply a transform, for example, a discrete cosine transform (DCT) or a discrete sine transform (DST) to the sample values ​​of the residual block 205, to obtain transform coefficients 207 in the transform domain. The transform coefficients 207 are also called transform residual coefficients and represent the residual block 205 in the transform domain.

[0082] The transform processing unit 206 may be configured to apply an integer approximation of a DCT / DST, such as a transform specified for H.265 / HEVC. Compared to an orthogonal DCT transform, such an integer approximation is typically scaled by a certain factor. In order to preserve the norm of the residual block processed by the forward transform and the inverse transform, an additional scaling factor is applied as part of the transform process. The scaling factor is typically selected based on certain constraints, such as a scaling factor that is a power of two of the shift operation, a bit depth of the transform coefficients, a trade-off between accuracy and implementation cost, etc. A specific scaling factor may be specified, for example, for the inverse transform, e.g., by the inverse transform processing unit 212 (and a corresponding inverse transform, e.g., by the inverse transform processing unit 312 in the video decoder 30), and the corresponding scaling factor of the forward transform, e.g., by the transform processing unit 206 in the encoder 20, may be specified accordingly.

[0083] An embodiment of the video encoder 20 (respectively the transform processing unit 206) may be configured to output transform parameters, e.g., one or more types of transform, encoded or compressed, e.g., directly or via the entropy encoding unit 270, such that the video decoder 30 may receive and use the transform parameters for decoding.

[0084] quantization The quantization unit 208 may be configured to quantize the transform coefficients 207, for example by applying scalar quantization or vector quantization, to obtain quantized coefficients 209. The quantized coefficients 209 may also be referred to as quantized transform coefficients 209 or quantized residual coefficients 209.

[0085] The quantization process may reduce the bit depth associated with some or all of the transform coefficients 207. For example, an n-bit transform coefficient may be rounded to an m-bit transform coefficient during quantization, where n is greater than m. The degree of quantization may be modified by adjusting a quantization parameter (QP). For example, in the case of scalar quantization, different scaling may be applied to achieve finer or coarser quantization. A smaller quantization step size corresponds to finer quantization and a larger quantization step size corresponds to coarser quantization. The applicable quantization step sizes may be indicated by a quantization parameter (QP). The quantization parameter may be, for example, an index into a predefined set of applicable quantization step sizes. For example, a small quantization parameter may correspond to fine quantization (small quantization step size) and a large quantization parameter may correspond to coarse quantization (large quantization step size), or vice versa. Quantization may include division by the quantization step size, and corresponding dequantization and / or inverse dequantization, e.g., by the inverse quantization unit 210, may include multiplication by the quantization step size. Some standard embodiments, e.g., HEVC, may be configured to use a quantization parameter to determine the quantization step size. In general, the quantization step size may be calculated based on the quantization parameter using a fixed-point approximation of an equation that includes a division. To restore the norm of the residual block, an additional scaling factor may be introduced in the quantization and dequantization, which may be corrected for the scaling used in the fixed-point approximation of the equation for the quantization step size and the quantization parameter. In one exemplary implementation, the scaling and dequantization of the inverse transform may be combined. Alternatively, customized quantization tables may be used and signaled, e.g., in the bitstream, from the encoder to the decoder. Quantization is a lossy operation, and the loss increases with increasing quantization step size.

[0086] An embodiment of the video encoder 20 (respectively, the quantization unit 208) may be configured to output a quantization parameter (QP), e.g., encoded directly or via the entropy encoding unit 270, such that the video decoder 30, for example, may receive and apply the quantization parameter for decoding.

[0087] inverse quantization Inverse quantization unit 210 is configured to apply the inverse quantization of quantization unit 208 to the quantized coefficients to obtain dequantized coefficients 211, e.g., by applying the inverse of the quantization scheme applied by quantization unit 208, e.g., based on or using the same quantization step size as quantization unit 208. The dequantized coefficients 211, also referred to as dequantized residual coefficients 211, may correspond to the transform coefficients 207, although they are not typically identical to the transform coefficients due to losses due to quantization.

[0088] Inverse transformation The inverse transform processing unit 212 is configured to apply an inverse transform of the transform applied by the transform processing unit 206, for example an inverse discrete cosine transform (DCT) or an inverse discrete sine transform (DST) or other inverse transform, to obtain a reconstructed residual block 213 (or corresponding dequantized coefficients 213) in the sample domain. The reconstructed residual block 213 may also be referred to as a transform block 213.

[0089] Rebuild The reconstruction unit 214 (e.g., an adder or analog summer 214) is configured to add the transform block 213 (i.e., the reconstructed residual block 213) to the prediction block 265, sample by sample, for example, by adding the sample values ​​of the reconstructed residual block 213 and the sample values ​​of the prediction block 265 to obtain a reconstructed block 215 in the sample domain.

[0090] filtering The loop filter unit 220 (or "loop filter" 220 for short) is configured to filter the reconstructed block 215 to obtain a filtered block 221, or in general, to filter the reconstructed samples to obtain filtered samples. The loop filter unit is configured, for example, to smooth pixel transitions or otherwise improve video quality. The loop filter unit 220 may include one or more loop filters, such as a deblocking filter, a sample adaptive offset (SAO) filter, or one or more other filters, for example, a bilateral filter, an adaptive loop filter (ALF), a sharpening, a smoothing filter, or a collaborative filter, or any combination thereof. Although in FIG. 2 the loop filter unit 220 is illustrated 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 referred to as a filtered reconstruction block 221.

[0091] An embodiment of video encoder 20 (respectively, loop filter unit 220) may be configured to output loop filter parameters (such as sample adaptive offset information), e.g., encoded directly or via entropy encoding unit 270, such that decoder 30, for example, may receive and apply the same loop filter parameters or respective loop filters for decoding.

[0092] Decoded Picture Buffer The decoded picture buffer (DPB) 230 may be a memory that stores reference pictures, or generally reference picture data, for encoding video data by the video encoder 20. The DPB 230 may be formed by any of a variety of memory devices, such as a dynamic random access memory (DRAM), including a synchronous dynamic random access memory (SDRAM), a magnetoresistive RAM (MRAM), a 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 further be configured to store other previously filtered blocks, e.g., previously reconstructed and filtered blocks 221 of the same current picture or a different picture, e.g., a previously reconstructed picture, and may provide, e.g., a complete previously reconstructed, i.e., decoded picture (and corresponding reference blocks and samples) and / or a partially reconstructed current picture (and corresponding reference blocks and samples), e.g., for inter prediction. The decoded picture buffer (DPB) 230 may also be configured to store one or more unfiltered reconstructed blocks 215, or unfiltered reconstructed samples in general, for example if the reconstructed blocks 215 are not filtered by the loop filter unit 220, or any other further processed version of the reconstructed blocks or samples.

[0093] Mode Selection (Partitioning and Prediction) The mode selection unit 260 includes a partitioning unit 262, an inter prediction unit 244, and an intra prediction unit 254, and is configured to receive or obtain original picture data, e.g., an original block 203 (current block 203 of current picture 17), as well as reconstructed picture data, e.g., filtered and / or unfiltered reconstructed samples or blocks of the same (current) picture, and / or filtered and / or unfiltered reconstructed samples or blocks from one or more previously decoded pictures, e.g., from a decoded picture buffer 230 or other buffer (e.g., line buffer, not shown). The reconstructed picture data is used as reference picture data for prediction, e.g., inter prediction or intra prediction, to obtain a prediction block 265 or predictor 265.

[0094] The mode selection unit 260 may be configured to determine or select a partitioning of the current block prediction mode (including no partitioning) and a prediction mode (e.g., intra or inter prediction mode) and generate a corresponding prediction block 265, which is used for calculation of the residual block 205 and reconstruction of the reconstructed block 215.

[0095] An embodiment of the mode selection unit 260 may be configured to select a partitioning and prediction mode (e.g., from those supported by or available to the mode selection unit 260) that provides the best match, or in other words the smallest residual (smallest residual means better compression for transmission or storage), or the smallest signaling overhead (smallest signaling overhead means better compression for transmission or storage), or considers or balances both. The mode selection unit 260 may be configured to determine the partitioning and prediction mode based on rate-distortion optimization (RDO), i.e., select the prediction mode that provides the smallest rate-distortion. Terms such as "best," "minimum," "optimum" in this context do not necessarily refer to an overall "best," "minimum," "optimum," etc., but may also refer to the satisfaction of a termination or selection criterion, such as a value above or below a threshold, or other constraint that may lead to a "suboptimal selection" but reduces complexity and processing time.

[0096] In other words, the partitioning unit 262 may be configured to partition the block 203 into smaller block partitions or sub-blocks (again forming blocks), e.g., using quad-tree partitioning (QT), binary tree partitioning (BT) or ternary tree partitioning (TT) or any combination thereof repeatedly, and, e.g., to perform prediction for each of the block partitions or sub-blocks, where the mode selection includes selecting a tree structure of the partitioning block 203, and a prediction mode is applied to each of the block partitions or sub-blocks.

[0097] In the following, the partitioning performed by the exemplary video encoder 20 (e.g., partitioning unit 262 2A and 2B, the prediction process (by the inter prediction unit 244 and the intra prediction unit 254) will be described in more detail.

[0098] Partitioning The partitioning unit 262 may partition (or split) the current block 203 into smaller partitions, e.g., small blocks of square or rectangular size. These smaller blocks (which may also be called sub-blocks) may be further partitioned into even smaller partitions. This is also called tree partitioning or hierarchical tree partitioning, where, for example, a root block at root tree level 0 (hierarchical level 0, depth 0) may be recursively partitioned, e.g., into two or more blocks at the next lower tree level, e.g., a node at tree level 1 (hierarchical level 1, depth 1), which may be partitioned again into two or more blocks at the next lower level, e.g., tree level 2 (hierarchical level 2, depth 2), and so on, until partitioning terminates, e.g., because a termination criterion is met, e.g., a maximum tree depth or a 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 a partitioning into two partitions is called a binary tree (BT), a tree that uses a partitioning into three partitions is called a ternary tree (TT), and a tree that uses a partitioning into four partitions is called a quad tree (QT).

[0099] As mentioned above, the term "block" as used herein may be a portion of a picture, particularly a square or rectangular portion. For example, with reference to HEVC and VVC, a block may be or correspond to a coding tree unit (CTU), a coding unit (CU), a prediction unit (PU), and a transform unit (TU), and / or a corresponding block, such as a coding tree block (CTB), a coding block (CB), a transform block (TB), or a prediction block (PB).

[0100] For example, a coding tree unit (CTU) may be or include a CTB of luma samples, two corresponding CTBs of chroma samples for a picture with three sample arrangements, or a CTB of a monochrome picture or a sample of a picture coded using three separate color planes and a syntax structure used to code the sample. Correspondingly, a coding tree block (CTB) may be an N×N block of samples for some value of N, such that the division of components into CTBs is a partitioning. A coding unit (CT) may be or include a coding block of luma samples, two corresponding coding blocks of chroma samples for a picture with three sample arrangements, or a coding block of samples for a monochrome picture or a picture coded using three separate color planes and a syntax structure used to code the sample. Correspondingly, a coding block (CB) may be an M×N block of samples for some values ​​of M and N, such that the division of a CTB into coding blocks is a partitioning.

[0101] In an embodiment, for example, according to HEVC, a coding tree unit (CTU) may be split into CUs by using a quadtree structure, denoted as a coding tree. The decision of whether to code a picture region using inter-picture (temporal) or intra-picture (spatial) prediction is made at the CU level. Each CU may be further split into one, two, or four PUs according to a PU split type. Within one PU, the same prediction process is applied, and related information is transmitted to the decoder on a PU basis. After obtaining a residual block by applying a prediction process based on the PU split type, the CU may be partitioned into transform units (TUs) according to another quadtree structure similar to the coding tree of the CU.

[0102] In an embodiment, according to the latest video coding standard currently under development, for example called Versatile Video Coding (VVC), a combined quad-tree and binary tree (QTBT) partitioning is used to partition, for example, coding blocks. In the QTBT block structure, a CU can have either a square or rectangular shape. For example, a coding tree unit (CTU) is first partitioned by a quad-tree structure. The quad-tree leaf node is further partitioned by a binary tree or a ternary (or triple) tree structure. The partitioning tree leaf node is called a coding unit (CU), and its segmentation is used for prediction and transformation processes without further partitioning. This means that CUs, PUs, and TUs have the same block size in the QTBT coding block structure. In parallel, multiple partitions, for example, ternary tree partitions, can be used with the QTBT block structure.

[0103] In one example, mode selection unit 260 of video encoder 20 may be configured to perform any combination of the partitioning techniques described herein.

[0104] As mentioned above, video encoder 20 may be configured to determine or select a best or optimal prediction mode from a (e.g., predetermined) set of prediction modes. The set of prediction modes may include, for example, intra-prediction modes and / or inter-prediction modes.

[0105] Intra prediction The set of intra prediction modes may include 35 different intra prediction modes, e.g., omnidirectional modes such as DC (or average) mode and planar mode, or directional modes as defined, e.g., in HEVC, and may include 67 different intra prediction modes, e.g., omnidirectional modes such as DC (or average) mode and planar mode, or directional modes as defined, e.g., in VVC.

[0106] The intra prediction unit 254 is configured to use reconstructed samples of neighboring blocks of the same current picture to generate an intra prediction block 265 according to an intra prediction mode of the set of intra prediction modes.

[0107] The intra prediction unit 254 (or, generally, the mode selection unit 260) is further configured to output the intra prediction parameters (or, generally, information indicating the selected intra prediction mode for the block) to the entropy encoding unit 270 in the form of syntax elements 266 for inclusion in the encoded picture data 21 so that the video decoder 30 can receive and use the prediction parameters for decoding.

[0108] Inter Prediction The set of inter prediction modes (or possible inter prediction modes) depends on the available reference pictures (i.e., previous, at least partially decoded pictures, e.g., those stored in DBP 230) and other inter prediction parameters, e.g., whether the entire reference picture or only a portion thereof, e.g., a search window region around the area of ​​the current block in the reference picture, is used to search for the best matching reference block, and / or whether pixel interpolation is applied, e.g., half / semi-pel and / or quarter-pel interpolation.

[0109] In addition to the above prediction modes, skip mode and / or direct mode may be applied.

[0110] The inter prediction unit 244 may include a motion estimation (ME) unit and a motion compensation (MC) unit (both not shown in FIG. 2). The motion estimation unit may be configured to receive or obtain the picture block 203 (current picture block 203 of current picture 17) and the decoded picture 231, or at least one or more previously reconstructed blocks, e.g., reconstructed blocks of one or more other / different previously decoded pictures 231, for motion estimation. For example, a video sequence may include the current picture and the previously decoded picture 231, or in other words, the current picture and the previously decoded picture 231 may be part of or form a sequence of pictures that form a video sequence.

[0111] The encoder 20 may be configured to, for example, select a reference block from multiple reference blocks of the same or different pictures of multiple other pictures, and to, for example, provide a reference picture (or a reference picture index) and / or an offset (spatial offset) between the position (x, y coordinates) of the reference block and the position of the current block as an inter-prediction parameter to the motion estimation unit. This offset is also called a motion vector (MV).

[0112] The motion compensation unit is configured to obtain, for example, receive, inter prediction parameters and perform inter prediction based on or using the inter prediction parameters to obtain the inter prediction block 265. The motion compensation performed by the motion compensation unit may include fetching or generating a prediction block based on a motion / block vector determined by motion estimation, possibly performing interpolation to sub-pixel accuracy. Interpolation filtering may generate additional pixel samples from known pixel samples, thus increasing the number of candidate prediction blocks that may be used to code the picture block. Upon receiving the motion vector of the PU of the current picture block, the motion compensation unit may locate the prediction block to which the motion vector points in one of the reference picture lists.

[0113] The motion compensation unit may also generate syntax elements associated with the blocks and video slices that are used by video decoder 30 in decoding picture blocks of the 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.

[0114] Entropy Coding The entropy encoding unit 270 is configured to, for example, apply an entropy encoding algorithm or scheme (e.g., a variable length coding (VLC) scheme, a context-adaptive VLC scheme (CAVLC), an arithmetic coding scheme, binarization, context-adaptive binary arithmetic coding (CABAC), syntax-based context-adaptive binary arithmetic coding (SBAC), probability interval partitioning entropy (PIPE) coding or other entropy encoding methodology or technique), or bypass (no compression) 209 of quantized coefficients, inter prediction parameters, intra prediction parameters, loop filter parameters and / or other syntax elements, to obtain encoded picture data 21, which may be output via an output 272, for example, in the form of an encoded bitstream 21, such that the video decoder 30 can receive the parameters and use them for decoding. The encoded bitstream 21 may be transmitted to the video decoder 30 or may be stored in a memory for later transmission or retrieval by the video decoder 30.

[0115] Other structural variations of the video encoder 20 can be used to encode the video stream. For example, the non-transform-based encoder 20 can directly quantize the residual signal for a particular block or frame without the transform processing unit 206. In other implementations, the encoder 20 can combine the quantization unit 208 and the inverse quantization unit 210 into a single unit.

[0116] Decoder and decoding method 3 illustrates an example of a video decoder 30 configured to implement the techniques of the present application. The video decoder 30 is configured to receive encoded picture data 21 (e.g., encoded bitstream 21), e.g., encoded by encoder 20, to obtain a decoded picture 331. The encoded picture data or bitstream includes information for decoding the encoded picture data, e.g., data representing picture blocks of encoded video slices (and / or tile groups or tiles) and associated syntax elements.

[0117] In the example of Figure 3, the decoder 30 includes an entropy decoding unit 304, an inverse quantization unit 310, an inverse transform processing unit 312, a reconstruction unit 314 (e.g., an analog summer 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. The video decoder 30 may, in some examples, perform a decoding path that is generally inverse to the encoding path described with respect to the video encoder 100 from Figure 2.

[0118] As described with respect to encoder 20, inverse quantization unit 210, inverse transform processing unit 212, reconstruction unit 214, loop filter 220, decoded picture buffer (DPB) 230, inter prediction unit 344, and intra prediction unit 354 are also referred to as forming a “built-in decoder” of video encoder 20. Thus, inverse quantization unit 310 is 210The inverse transform processing unit 312 may be functionally identical to the inverse transform 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. Oye Encoder 20 The descriptions provided for the respective units and functions of the video decoder 30 correspond to the respective units and functions of the video decoder 30.

[0119] Entropy Decoding The entropy decoding unit 304 is configured to parse the bitstream 21 (or generally the encoded picture data 21) and, e.g., perform entropy decoding on the encoded picture data 21, e.g., to obtain some or all of the quantized coefficients 309 and / or decoded coding parameters (not shown in FIG. 3), e.g., inter-prediction parameters (e.g., reference picture indexes and motion vectors), intra-prediction parameters (e.g., intra-prediction modes or indices), transform 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 the encoding scheme, as described with respect to the entropy encoding 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 provide other parameters to other units of the decoder 30. The video decoder 30 may receive syntax elements at a video slice level and / or a 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.

[0120] inverse quantization Inverse quantization unit 310 may be configured to receive a quantization parameter (QP) (or information generally related to inverse quantization) and quantized coefficients from encoded picture data 21 (e.g., by parsing and / or decoding by entropy decoding unit 304), and apply inverse quantization to the decoded quantized coefficients 309 based on the quantization parameter to obtain unquantized coefficients 311, also referred to as transform coefficients 311. The inverse quantization process may include using the quantization parameter determined by video encoder 20 for each video block within a video slice (or a tile or tile group) to determine the degree of quantization, and similarly, the degree of inverse quantization to be applied.

[0121] Inverse transformation The inverse transform processing unit 312 may be configured to receive the unquantized coefficients 311, also referred to as transform coefficients 311, and to apply a transform to the unquantized coefficients 311 to obtain a reconstructed residual block 213 in the sample domain. The reconstructed residual block 213 may also be referred to as a transform block 313. The transform may be an inverse transform, e.g., an inverse DCT, an inverse DST, an inverse integer transform, or a conceptually similar inverse transform process. The inverse transform processing unit 312 may further be configured to receive transform parameters or corresponding information from the encoded picture data 21 (e.g., by parsing and / or decoding, e.g., by the entropy decoding unit 304) to determine a transform to apply to the unquantized coefficients 311.

[0122] Rebuild The reconstruction unit 314 (e.g., an adder or analog adder 314) may be configured to add the reconstructed residual block 313 to the prediction block 365, for example, by adding sample values ​​of the reconstructed residual block 313 and sample values ​​of the prediction block 365, to obtain a reconstructed block 315 in the sample domain.

[0123] filtering A loop filter unit 320 (either in the coding loop or after the coding loop) is configured to filter the reconstructed block 315, e.g., to smooth pixel transitions or otherwise improve video quality, to obtain a filtered block 321. 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, e.g., a bilateral filter, an adaptive loop filter (ALF), a sharpening, a smoothing filter, or a collaborative filter, or any combination thereof. Although in FIG. 3, the loop filter unit 320 is shown as an in-loop filter, in other configurations, the loop filter unit 320 may be implemented as a post-loop filter.

[0124] Decoded Picture Buffer The decoded video blocks 321 of the picture are then stored in a decoded picture buffer 330, which stores the decoded picture 331 as a reference picture for subsequent motion compensation of other pictures and / or for their respective output display.

[0125] The decoder 30 outputs the decoded picture 331 to a user, for presentation or viewing, for example via output 312.

[0126] 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 identical in function to the inter prediction unit 254, performing split or partitioning decisions and predictions based on partitioning and / or prediction parameters, or respective information, received from the encoded picture data 21 (e.g., by parsing and / or decoding, by the entropy decoding unit 304). The mode application unit 360 may be configured to perform prediction (intra prediction or inter prediction) for each block based on the reconstructed picture, block, or respective samples (filtered or unfiltered) to obtain a prediction block 365.

[0127] If the 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 predictive block 365 of a picture block of the current video slice based on the signaled intra prediction mode and data from a previously decoded block of the current picture. If the video picture is coded as an inter-coded (i.e., B or P) slice, the inter prediction unit 344 (e.g., a motion compensation unit) of the mode application unit 360 is configured to generate a predictive block 365 of a video block of the current video slice based on the motion vector and other syntax elements received from the entropy decoding unit 304. For inter prediction, the predictive block may be generated from one of the reference pictures included in one of the reference picture lists. The video decoder 30 may construct the reference frame lists, List 0 and List 1, using a default construction technique based on the reference pictures stored in the DPB 330. The same or similar may apply to or depending on the embodiment that uses 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), e.g., video may be coded using I, P, or B tile groups and / or tiles.

[0128] Mode application unit 360 is configured to determine prediction information for video blocks of the current video slice by parsing motion vectors or related information and other syntax elements, and uses the prediction information to generate predictive blocks for the current video block being decoded. For example, mode application unit 360 uses some of the received syntax elements to determine a prediction mode (e.g., intra or inter prediction) used to code the video blocks of the video slice, an inter prediction slice type (e.g., B slice, P slice, or GPB slice), construction information of one or more of the reference picture lists of the slice, a motion vector for each inter encoded video block of the slice, an inter prediction status for each inter coded video block of the slice, and other information for decoding video blocks in the current video slice. The same or similar may apply to or depending on the embodiment that uses 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), e.g., video may be coded using I, P, or B tile groups and / or tiles.

[0129] The embodiment of video decoder 30 shown in FIG. 3 may be configured to partition and / or decode a picture by using slices (also referred to as video slices), and a picture may be partitioned or decoded using one or more slices (typically non-overlapping), and each slice may include one or more blocks (e.g., CTUs).

[0130] The embodiment of video decoder 30 shown in FIG. 3 may be configured to partition and / or decode a picture by using tile groups (also referred to as video tile groups) and / or tiles (also referred to as video tiles), and a picture may be partitioned or decoded using one or more tile groups (typically non-overlapping), each tile group may include, for example, one or more blocks (e.g., CTUs) or one or more tiles, and each tile may be, for example, rectangular, may include one or more blocks (e.g., CTUs), and may be, for example, a full block or a partial block.

[0131] Other variations of the video decoder 30 may be used to decode the encoded picture data 21. For example, the decoder 30 may generate an output video stream without the loop filtering unit 320. For example, the non-transform-based decoder 30 may directly inverse quantize the residual signal for a particular block or frame without the inverse transform processing unit 312. In other implementations, the video decoder 30 may combine the inverse quantization unit 310 and the inverse transform processing unit 312 into a single unit.

[0132] It should be understood that in the encoder 20 and the decoder 30, the processing result of the current step may be further processed and output to the next step. For example, after the interpolation filtering, the motion vector derivation, or the loop filtering, further operations such as clipping or shifting may be performed on the processing result of the interpolation filtering, the motion vector derivation, or the loop filtering.

[0133] It should be noted that further operations (including but not limited to control point motion vectors in affine mode, sub-block motion vectors in affine, planar, ATMVP modes, temporal motion vectors, etc.) may be applied to the derived motion vector of the current block. For example, the value of the motion vector is restricted to a predefined range according to its representation bit. If the representative bit of the motion vector is bitDepth, the range is 2^(bitDepth-1) to 2^(bitDepth-1)-1, where "^" means exponentiation. For example, if bitDepth is set equal to 16, the range is -32768 to 32767, and if bitDepth is set equal to 18, the range is -131072 to 131071. For example, the value of the derived motion vector (e.g., MVs of four 4x4 sub-blocks in one 8x8 block) is constrained such that the maximum difference between the integer parts of the four 4x4 sub-block MVs is less than or equal to N pixels, such as less than or equal to 1 pixel. Here we present two methods for constraining motion vectors according to bitDepth.

[0134] Method 1: Remove the overflow MSB (Most Significant Bit) by using flow arithmetic ux=(mvx+2 bitDepth ) % 2 bitDepth (1) mvx=( ux >= 2 bitDepth-1 ) ? (ux - 2 bitDepth ) : ux (2) uy=(mvy+2 bitDepth ) % 2 bitDepth (3) mvy=( uy >= 2 bitDepth-1 ) ? (uy - 2 bitDepth ) : uy (4) In the above formula, mvx is the horizontal component of the motion vector of the image block or sub-block, mvy is the vertical component of the motion vector of the image block or sub-block, and ux and uy denote intermediate values.

[0135] For example, if the value of mvx is -32769, then after applying equations (1) and (2), the resulting value will be 32767. In computer systems, decimal numbers are stored as two's complement numbers. The two's complement of -32769 is 1, 0111, 1111, 1111, 1111 (17 bits) and since the MSB is discarded, the resulting two's complement is 0111, 1111, 1111, 1111 (decimal 32767), which is the same as the output by applying equations (1) and (2). ux=(mvpx + mvdx +2 bitDepth ) % 2 bitDepth (5) mvx=( ux >= 2 bitDepth-1 ) ? (ux - 2 bitDepth ) : ux (6) uy=(mvpy + mvdy +2 bitDepth ) % 2 bitDepth (7) mvy=( uy >= 2 bitDepth-1 ) ? (uy - 2 bitDepth ) : uy (8)

[0136] An operation may be applied between the sums of mvp and mvd as shown in equations (5) through (8).

[0137] Method 2: Remove the overflow MSB by clipping the value vx=Clip3(-2 bitDepth-1 , 2 bitDepth-1 -1, vx) vy=Clip3(-2 bitDepth-1 , 2 bitDepth-1 -1, vy) In the above equation, vx is the horizontal component of the motion vector of the image block or sub-block, vy is the vertical component of the motion vector of the image block or sub-block, x, y, and z correspond to the three input values ​​of the MV clipping process respectively, and the definition of the function Clip3 is as follows:

[0138]

number

[0139] 4 is a schematic diagram of a video coding device 400 according to one embodiment of the present disclosure. The video coding device 400 is suitable for implementing the disclosed embodiments described herein. In one embodiment, the video coding device 400 may be a decoder, such as the video decoder 30 of FIG. 1A, or an encoder, such as the video encoder 20 of FIG. 1A.

[0140] Video coding device 400 includes an input 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 output port 450 (or output port 450) for transmitting data, and a memory 460 for storing data. Video coding device 400 may also include optical-electrical (OE) and electrical-optical (EO) components coupled to the input port 410, the receiver unit 420, the transmitter unit 440, and the output port 450 for entering and leaving optical or electrical signals.

[0141] The processor 430 is implemented by hardware and software. The processor 430 may be implemented as one or more CPU chips, cores (e.g., as a multi-core processor), FPGA, ASIC, and DSP. 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 above-disclosed embodiments. For example, the coding module 470 implements, processes, prepares, or provides various coding operations. Thus, the inclusion of the coding module 470 significantly improves the functionality of the video coding device 400 and transforms the video coding device 400 into a different state. Alternatively, the coding module 470 is implemented as instructions stored in the memory 460 and executed by the processor 430.

[0142] Memory 460 may include one or more disks, tape drives, and solid state drives, and may be used as an overflow data storage device to store programs when such programs are selected for execution and to store instructions and data read during execution of the programs. 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).

[0143] FIG. 5 is a simplified block diagram of an apparatus 500 that may be used as either or both of source device 12 and destination device 14 of FIG. 1, according to an example embodiment.

[0144] The processor 502 in the device 500 may be a central processing unit. Alternatively, the processor 502 may be any other type of device or devices capable of manipulating or processing information, now existing or later developed. Although the disclosed implementations may be implemented with a single processor, e.g., processor 502, as shown, advantages of speed and efficiency may be achieved using multiple processors.

[0145] The memory 504 in the device 500 may be a read-only memory (ROM) device or a random access memory (RAM) device in implementation. Any other suitable type of storage device may be used as the memory 504. The memory 504 may include code and data 506 accessed by the processor 502 using a bus 512. The memory 504 may further include an operating system 508 and application programs 510, which include at least one program that allows the processor 502 to perform the methods described herein. For example, the application programs 510 may include applications 1 to N, which further include a video coding application that performs the methods described herein.

[0146] The apparatus 500 may also include one or more output devices, such as a display 518. The display 518, in one example, may be a touch-sensitive display that combines a display with a touch-sensitive element operable to sense touch input. The display 518 may be coupled to the processor 502 via the bus 512.

[0147] Although shown herein as a single bus, bus 512 of device 500 may be comprised of multiple buses. Additionally, secondary storage 514 may be directly coupled to other components of device 500 or may be accessible over 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 may be implemented in a wide variety of configurations.

[0148] background Parameter Set The parameter sets are fundamentally similar and share the same fundamental design goals: bitrate efficiency, error resilience, and providing a system layer interface. HEVC (H.265) has a hierarchy of parameter sets, including video parameter sets (VPS), sequence parameter sets (SPS), and picture parameter sets (PPS), similar to their counterparts in AVC and VVC. Each slice references a single active PPS, SPS, and VPS to access information used to decode the slice. The PPS contains information that applies to all slices in a picture, so all slices in a picture must reference the same PPS. Slices in different pictures can also reference the same PPS. Similarly, the SPS contains information that applies to all pictures in the same coded video sequence.

[0149] Although the PPS may vary for individual pictures, it is common for many or all pictures in a coded video sequence to reference the same PPS. Reusing parameter sets is bitrate efficient, since it eliminates the need to transmit shared information multiple times, and it is loss tolerant, since the contents of the parameter sets can be carried by more reliable external communication links or repeated frequently within the bitstream to ensure they are not lost.

[0150] Sequence Parameter Set (SPS): A syntax structure containing zero or more syntax elements that apply across CLVS, determined by the contents of syntax elements in the PPS referenced by syntax elements in each picture header.

[0151] Scalable Video Coding, Layers, and Video Parameter Sets (VPS) Scalable video coding provides a mechanism for coding video in multiple layers, with each layer representing a different quality representation of the same video scene. The base layer is the lowest quality representation. One or more enhancement layers (ELs) may be coded to provide improved video quality by referencing lower layers. Decoding a subset of the layers of a scalable coded video bitstream results in lower quality video than if the full bitstream were decoded, but still acceptable video. This allows for a more gradual degradation compared to non-scalable video bitstreams, where lowering the bitrate typically results in a significant degradation of video quality, often quickly becoming unwatchable.

[0152] In a scalable video sequence, there are multiple types of scalability, such as temporal scalability, spatial scalability, and quality scalability. Figure 8 provides an example showing both spatial and temporal scalability. In Figure 8, there are two layers coded with different resolutions. BL is lower resolution and EL is higher resolution, and spatial scalability is achieved by providing a decoder that decodes BL, EL, or both.

[0153] In addition to spatial scalability, temporal scalability is achieved within the coding layers. In this example, each coding layer is divided into two temporal sub-layers, labeled by temporal IDs 0 and 1, respectively. Temporal scalability is achieved by providing a decoder to decode temporal sub-layer 0 (temporal ID equals 0) or both sub-layers 0 and 1.

[0154] Pictures in different layers are assigned different layer IDs, i.e. the syntax element nuh_layer_id. A Coding Layer Video Sequence (CLVS) is a sequence of pictures with the same value of nuh_layer_id, and consists of a special Coding Layer Video Sequence that starts, in decoding order, with a coding picture (CLVSS, e.g., an intra picture), followed by zero or more pictures that are not CLVSS pictures, including all subsequent pictures up to, but not including, any subsequent pictures that are CLVSS pictures.

[0155] A coded video sequence (CVS) to which a VPS can be applied is composed of one or more coded layer video sequences (CLVS). In the example of Figure 8, assuming that the first pictures of BL and EL are CLVSS pictures and all other pictures are not CLVSS pictures, this is a CVS composed of two CLVS.

[0156] Pictures in different layers at the same position (such as A and B in Figure 8) form an access unit (AU). An access unit consists of a set of pictures that belong to different layers and contain coded pictures associated with the same time output from the decoded picture buffer.

[0157] The layers include independent layers or dependent layers, where the dependent layers predict the need to use inter-layer prediction by referring to one or more of their reference layers, where the layer ID of the reference layer may be smaller than the layer ID of the dependent layer. The independent layers are predicted without using inter-layer prediction.

[0158] The following table is an example of syntax elements that may be signaled in the VPS.

[0159] [Table 1A]

[0160] [Table 1B]

[0161] [Table 1C]

[0162] For example, vps_video_parameter_set_id represents an ID that can be referenced by the SPS introduced in the next section.

[0163] For example, vps_max_layers_minus1+1 represents the maximum number of layers allowed in a CVS.

[0164] For example, vps_max_sublayers_minus1+1 represents the maximum number of temporal sublayers allowed in a CV.

[0165] For example, vps_all_layers_same_num_sublayers_flag characterizes a CVS whose all coding layers contain the same number of temporal sublayers. It is signaled only if the maximum number of layers allowed and the maximum number of temporal sublayers allowed are greater than 1.

[0166] For example, vps_all_independent_layers_flag characterizes the CVS such that all coding layers are independent layers, i.e., there are no inter-layer reference pictures in each layer. Inter-layer reference pictures may be used when inter prediction uses pictures from other layers rather than the same layer.

[0167] For example, vps_layer_id[i], for i in the range 0 to vps_max_layers_minus1, inclusive, represents the layer IDs of each layer, from layer index 0 to vps_max_layers_minus1. Note the distinction between layer indexes and layer IDs. WorthYes. vps_layer_id[0] gives the ID of the 0th layer, which may not be equal to 0.

[0168] For simplicity, this document skips the introduction of the remaining syntax elements: please refer to VVC Draft 8 for their description.

[0169] Sequence Parameter Set (SPS) An SPS applies to one or more layers of a coded video sequence and contains parameters that do not change from picture to picture in the coded video sequence. In particular, an SPS contains information signaling subpictures.

[0170] The following table shows a snapshot of some of the sub-picture signaling in the SPS of ITU JVET-Q2001-v13, and the download links are as follows: http: / / phenix.it-sudparis.eu / jvet / doc_end_user / documents / 17_Brussels / wg11 / JVET-Q2001-v13.zip. In the remainder of this application, this prior art document will be designated VVC Draft 8 for simplicity.

[0171] [Table 2A]

[0172] [Table 2B]

[0173] If sps_video_parameter_set_id is greater than 0, it specifies the value of vps_video_parameter_set_id of the VPS referenced by the SPS.

[0174] If sps_video_parameter_set_id is equal to 0, the following applies: -The SPS does not refer to the VPS, and the VPS is not referenced when decoding each CLVS by referencing the SPS. A value of -vps_max_layers_minus1 is inferred to be equal to 0. - A CVS shall contain only one layer (i.e., all VCL NAL units in a CVS shall have the same value of nuh_layer_id).

[0175] Several syntax elements in the SPS signal the position information and control flags of each sub-picture. The position information of the ith sub-picture includes: subpic_ctu_top_left_x[i] gives the horizontal component of the top left coordinate of subpicture i in the picture, or subpic_ctu_top_left_y[i] gives the vertical component of the top-left coordinate of subpicture i in the picture, or subpic_width_minus1[i] gives the width of subpicture i within the picture, or · subpic_height_minus1[i] gives the height of subpicture i within the picture.

[0176] Some syntax elements, for example sps_num_subpics_minus1, indicate the number of subpictures in a picture.

[0177] Partitioning a picture into CTUs, slices, tiles, and subpictures

[0178] Partitioning a picture into CTUs A picture is partitioned into a sequence of coding tree units (CTUs). The term CTB (coding tree block) is sometimes used interchangeably. The concept of a CTU is the same as that of HEVC. For a picture with three sample arrays, a CTU consists of an NxN block of luma samples and two corresponding blocks of chroma samples. Figure 6 shows an example of partitioning a picture into CTUs. The size of CTUs within a frame must be the same, except for those at picture boundaries (where incomplete CTUs may exist).

[0179] Partitioning a Picture into Tiles When tiling is enabled, the picture is divided into rectangular groups of CTUs separated by vertical and / or horizontal boundaries. Vertical and horizontal tile boundaries, respectively, divide the picture into Top to bottom , and crossing from the left picture boundary to the right picture boundary. The bitstream contains instructions related to the location of the aforementioned horizontal and vertical tile boundaries.

[0180] Partitioning a Picture into Slices The concept of slices provides a partitioning of pictures so that each slice can be decoded independently of other slices of the same picture, where decoding refers to entropy, residual and predictive decoding. The difference with tiles is that slices can have a more arbitrary shape (making the partitioning possibilities more flexible) and the purpose of slice partitioning is not parallelism but packet size matching and error resilience in the transmission environment.

[0181] A slice may consist of a complete picture and its parts. In HEVC, a slice consists of CTUs of multiple consecutive pictures in processing order. A slice is identified by its starting CTU address, which is signaled in the slice header or picture parameter set or other unit.

[0182] In VVC draft 8, a slice contains an integer number of complete tiles, or an integer number of contiguous CTU rows within a tile of a picture. Thus, each vertical slice boundary is always also a vertical tile boundary. It is possible that a horizontal boundary of a slice is not a tile boundary, but contains a horizontal CTU boundary within a tile, which occurs when a tile is split into multiple rectangular slices, where each slice contains an integer number of contiguous complete CTU rows within the tile.

[0183] In some examples, there are two slice modes: raster scan slice mode and rectangular slice mode. In raster scan slice mode, a slice contains a sequence of tiles in a tile raster scan of the picture. In rectangular slice mode, a slice contains multiple tiles that collectively form a rectangular region of the picture, or a slice contains multiple contiguous CTU rows of one tile that collectively form a rectangular region of the picture. The tiles in a rectangular slice are scanned in tile raster scan order within the rectangular region corresponding to the slice.

[0184] All slices of a picture collectively form the whole picture, i.e., every CTU of a picture must be contained in one of the picture's slices. Similar rules apply to tiles and subpictures.

[0185] Partitioning a picture into subpictures Subpicture rectangular partition of a picture. A subpicture can be an entire picture or a portion of a picture. A subpicture is a partitioning of a picture such that each subpicture is independently decodable from other subpictures in the entire video sequence. In VVC Draft 8, this is the case if indicated in the bitstream. That is, if the subpic_treated_as_pic_flag[i] indication applies for subpicture i, then that subpicture i is independently decodable from other subpictures in the entire video sequence.

[0186] The difference between a subpicture and a tile or slice is that a subpicture creates an independently decodable video sequence within a video sequence, whereas for tiles and slices, independent decoding is only guaranteed within one picture of a video sequence.

[0187] In VVC Draft 8, a subpicture contains one or more slices that collectively cover a rectangular region of the picture. Thus, each subpicture boundary is always a slice boundary, and each vertical subpicture boundary is always a vertical tile boundary.

[0188] FIG. 7 provides examples of tiles, slices, and subpictures.

[0189] 7, the picture is partitioned into 2 16 CTUs, 4 tiles, 4 slices, and 3 subpictures. The value of sps_num_subpics_minus1 is 2, and the position-related syntax elements have the following values: For subpicture 0 · subpic_ctu_top_left_x[0] is not signaled but is inferred to be 0. · subpic_ctu_top_left_y[0] is not signaled but is inferred to be 0. subpic_width_minus1[0], with a value of 8. subpic_height_minus1[0], with a value of 11. For subpicture 1 subpic_ctu_top_left_x[1], with a value of 9. subpic_ctu_top_left_y[1], with a value of 0. subpic_width_minus1[1], with a value of 8. subpic_height_minus1[1], with a value of 5. For subpicture 2 subpic_ctu_top_left_x[2], its value is 9. subpic_ctu_top_left_y[2], with a value of 6. · subpic_width_minus1[2] is not signaled but is inferred to be 8. · subpic_height_minus1[2] is not signaled but is inferred to be 5.

[0190] The coded bitstream is composed of Network Abstraction Layer (NAL) units, which are syntactic structures that contain an indication of the type of data to follow and the bytes that contain that data, in the form of a Raw Byte Sequence Payload (RBSP), interspersed with emulation prevention bytes as necessary.

[0191] The RBSP is a syntax structure that contains an integer number of bytes encapsulated in a NAL unit, either empty or in the form of a string of data bits containing syntax elements, followed by an RBSP stop bit and zero or more trailing bits equal to 0. The emulation prevention byte is a byte equal to 0x03.

[0192] A parameter set such as an SPS or a VPS is encapsulated in a NAL unit. Except for the syntax element information specified in the SPS and VPS, there is a NAL unit header for each NAL unit. The NAL unit header provides information such as layer ID (i.e., syntax nuh_layer_id), NAL unit type (i.e., syntax nal_unit_type), etc. For example, the NAL unit type of a NAL unit containing a VPS is VPS_NUT, and the NAL unit type of a NAL unit containing an SPS is SPS_NUT.

[0193] In general, NAL units in a bitstream can be divided into two classes: video coding layer (VCL) NAL units and non-VCL NAL units. NAL units that contain parameter sets (such as VPS or SPS) that do not provide the intrinsic coded data of a picture belong to the non-VCL NAL unit type. In contrast, NAL units that contain the intrinsic coded data of a picture (such as I-picture coded video data) are called VCL NAL units.

[0194] Table 5 of VVC Draft 8 defines the NAL unit types for each NAL unit and their classification.

[0195] For further details, please see VVC Draft 8.

[0196] Decoding process for constructing reference picture list This process is invoked at the start of the decoding process for each slice of a picture.

[0197] Reference pictures are addressed through a reference index, which is an index into the RPL. When decoding an I slice, the RPL is not used when decoding the slice data. When decoding a P slice, only RPL0 (i.e., RefPicList[0]) is used for decoding the slice data. When decoding a B slice, both RPL0 and RPL1 (i.e., RefPicList[1]) are used for decoding the slice data.

[0198] At the beginning of the decoding process for each slice of a picture, the RPLs RefPicList[0] and RefPicList[1] are derived. The RPL is used for marking reference pictures as specified in section 8.3.3 or for decoding slice data. NOTE 1 - For an I-slice of a picture, RefPicList[0] and RefPicList[1] may be derived for the purposes of bitstream conformance checking, but their derivation is not required for decoding of the current picture or pictures that follow the current picture in decoding order. For a P-slice of a picture, RefPicList[1] may be derived for the purposes of bitstream conformance checking, but its derivation is not required for decoding of the current picture or pictures that follow the current picture in decoding order.

[0199] If sps_idr_rpl_present_flag is equal to 0, pps_rpl_info_in_ph_flag is equal to 0, and nal_unit_type is equal to IDR_W_RADL or IDR_N_LP, then RPL RefPicList[0] and RefPicList[1] are both derived to be empty, i.e., to contain 0 entries, and the following applies for each i equal to 0 or 1: The value of RplsIdx[i] is inferred to be equal to sps_num_ref_pic_lists[i]. The value of num_ref_entries[i][RplsIdx[i]] is inferred to be equal to 0. The value of NumRefIdxActive[i] is inferred to be equal to 0.

[0200] Otherwise, the RPL 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 RprConstraintsActiveFlag[0][j] and RprConstraintsActiveFlag[1][j] are derived as follows: for( i = 0 ; i < 2 ; i++ ) { for( j = 0, k = 0, pocBase = PicOrderCntVal; j < num_ref_entries[i][RplsIdx[i]]; j++) { if( !inter_layer_ref_pic_flag[i][RplsIdx[i]][j] ) { if( st_ref_pic_flag[i][RplsIdx[i]][j] ) { RefPicPocList[i][j] = pocBase+DeltaPocValSt[i][RplsIdx[i]][j] if( there is a reference picture picA in the DPB with the same nuh_layer_id as the current picture and PicOrderCntVal equal to RefPicPocList[i][j] ) RefPicList[i][j] = picA else RefPicList[i][j] = "no reference picture" (200) pocBase = RefPicPocList[i][j] }else{ if( !delta_poc_msb_cycle_present_flag[i][k] ) { if(there is a reference picA in the DPB with the same nuh_layer_id as the current picture and PicOrderCntVal&(MaxPicOrderCntLsb-1) equal to PocLsbLt[i][k] ) RefPicList[i][j] = picA else RefPicList[i][j] = "no reference picture" RefPicLtPocList[i][j] = PocLsbLt[i][k] } else { if( there is a reference picA in the DPB with the same nuh_layer_id as the current picture and PicOrderCntVal equal to FullPocLt[i][k] ) RefPicList[i][j] = picA else RefPicList[i][j] = "no reference picture" RefPicLtPocList[i][j] = FullPocLt[i][k] } k++ } } else { layerIdx = DirectRefLayerIdx[GeneralLayerIdx[nuh_layer_id]][ilrp_idx[i][RplsIdx[i]][j]] refPicLayerId = vps_layer_id[layerIdx] if( there is a reference picture picA in the DPB with nuh_layer_id equal to refPicLayerId and the same PicOrderCntVal as the current picture ) RefPicList[i][j] = picA else RefPicList[i][j] = "no reference picture" } fRefWidth is set equal to CurrPicScalWinWidthL of the reference picture RefPicList[i][j] fRefHeight is set equal to CurrPicScalWinHeightL of the reference picture RefPicList[i][j] refPicWidth, refPicHeight, refScalingWinLeftOffset, refScalingWinRightOffset, refScalingWinTopOffset, and refScalingWinBottomOffset, are set equal to the values of pps_pic_width_in_luma_samples, pps_pic_height_in_luma_samples, pps_scaling_win_left_offset, pps_scaling_win_right_offset, pps_scaling_win_top_offset, and pps_scaling_win_bottom_offset, respectively, of the reference picture RefPicList[i][j] fRefNumSubpics is set equal to sps_num_subpics_minus1 of the reference picture RefPicList[i][j] RefPicScale[i][j][0] = ((fRefWidth<<14)+(CurrPicScalWinWidthL>>1)) / CurrPicScalWinWidthL RefPicScale[i][j][1] = ((fRefHeight<<14)+(CurrPicScalWinHeightL>>1)) / CurrPicScalWinHeightL RprConstraintsActiveFlag[i][j] = ( pps_pic_width_in_luma_samples != refPicWidth || pps_pic_height_in_luma_samples != refPicHeight || pps_scaling_win_left_offset != refScalingWinLeftOffset || pps_scaling_win_right_offset != refScalingWinRightOffset || pps_scaling_win_top_offset != refScalingWinTopOffset || pps_scaling_win_bottom_offset != refScalingWinBottomOffset || sps_num_subpics_minus1 != fRefNumSubpics ) } }

[0201] 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].

[0202] Problem and solution description Problem 1 A VPS is an arbitrary set of parameters. For example, in the case of a single-layer bitstream, there may be no VPS in the bitstream. It has been observed that the semantics of some syntax elements in a VPS are incomplete. If a VPS is not in a bitstream, there is no definition for them.

[0203] For example, in VVC draft 8, the semantics of the syntax element vps_max_layers_minus1 is specified as follows: vps_max_layers_minus1+1 specifies the maximum number of layers allowed in each CVS that references the VPS.

[0204] EMBODIMENT 1 According to the first embodiment, to account for the case where a VPS is not present in the bitstream, the semantics of vps_max_layers_minus1 are modified as follows: vps_max_layers_minus1+1 specifies the maximum number of layers allowed in each CV that references a VPS. In the absence, the value of vps_max_layers_minus1 is inferred to be equal to 0.

[0205] In other words, if VPS doesn't exist. CVS only has one tier.

[0206] Second problem The other syntax element vps_layer_id[i] in the range 0 to vps_max_layers_minus in VPS has the same problem, i.e. it does not specify an inferred value if no VPS is present. The semantics of vps_layer_id[i] are specified in VVC draft 8 as follows: 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] shall be less than vps_layer_id[n]. nuh_layer_id represents the layer ID. vps_layer_id[i] specifies the layer ID of the i-th layer. This definition also constrains that if there are more layers, the layer ID of the higher layer (with layer index n) must be greater than the layer ID of the lower layer (with layer index m), i.e., the layer IDs specified in the vps_layer_id array are in ascending order.

[0207] Note that the value of vps_layer_id[i] is used to derive some intermediate variables in VVC draft 8. For example, the derivation of the variable OutputLayerIdInOls[0][0] depends on the value of vps_layer_id[i] for i in the range 0 to vps_max_layers_minus1, inclusive, and OutputLayerIdInOls[0][0] may be further used to determine the decoding process as specified in clause 8.1.2 of VVC draft 8. If a VPS is not present in the bitstream, the decoding process may be undefined since the value of OutputLayerIdInOls[0][0] is undefined due to the absence of an inferred value of vps_layer_id[i] for i in the range 0 to vps_max_layers_minus1, inclusive.

[0208] EMBODIMENT 2 According to the second embodiment, to account for the case where a VPS is not present in the bitstream, the semantics of vps_layer_id[i] are modified as follows: 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] shall be less than vps_layer_id[n]. In the absence, vps_layer_id[0] is inferred to be equal to the value of nuh_layer_id in the sequence parameter set (SPS).

[0209] In other words, if there is no VPS, there is only one video coding layer: the syntax element vps_layer_id array can have only one entry (i.e., the 0th layer), whose value vps_layer_id[0] is inferred to be equal to the layer ID of the SPS.

[0210] EMBODIMENT 3 According to the third embodiment, to account for the case where a VPS is not present in the bitstream, the semantics of vps_layer_id[i] are modified as follows: 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, the value of vps_layer_id[m] shall be less than vps_layer_id[n] if m is less than n. In the absence, vps_layer_id[0] is inferred to be equal to the value of nuh_layer_id of the first non-VCL NAL unit.

[0211] In other words, if no VPS is present, there is only one video coding layer: the syntax element vps_layer_id array can have only one entry (i.e., the 0th layer), whose value vps_layer_id[0] is inferred to be equal to the value of the layer ID of the non-VCL NAL unit.

[0212] EMBODIMENT 4 According to the fourth embodiment, to account for the case where a VPS is not present in the bitstream, the semantics of vps_layer_id[i] are modified as follows: 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, the value of vps_layer_id[m] shall be less than vps_layer_id[n] if m is less than n. In the absence, vps_layer_id[0] is inferred to be equal to the value of nuh_layer_id of the first VCL NAL unit.

[0213] In other words, if no VPS is present, there is only one video coding layer: the syntax element vps_layer_id array can have only one entry (i.e., the 0th layer), whose value vps_layer_id[0] is inferred to be equal to the value of the layer ID of the VCL NAL unit.

[0214] EMBODIMENT 5 According to the fifth embodiment, to account for the case where a VPS is not present in the bitstream, the semantics of vps_layer_id[i] are modified as follows: 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, the value of vps_layer_id[m] shall be less than vps_layer_id[n] if m is less than n. In the absence, vps_layer_id[0] is inferred to be equal to the value of nuh_layer_id of any NAL unit.

[0215] In other words, if no VPS is present, there is only one video coding layer, i.e., all NAL units have the same value of nuh_layer_id in their NAL unit headers. The syntax element vps_layer_id array can have only one entry (i.e., the 0th layer), whose value vps_layer_id[0] is inferred to be equal to the value of layer ID of any NAL unit.

[0216] According to the above description, a method for decoding a video bitstream and a method for encoding a video bitstream are provided herein. Correspondingly, an apparatus for decoding a (coded) video bitstream and an apparatus for decoding a video bitstream are provided herein.

[0217] FIG. 9 shows a method of decoding a video bitstream implemented by a decoding device, the bitstream including data representing a current video coding layer, the method including step 910 of determining whether the current video coding layer is the only layer in the bitstream, and step 920 of using an identifier of a NAL unit of the current video coding layer (e.g., nuh_layer_id) as an identifier of the current video coding layer (e.g., vps_layer_id) if (e.g., determined only if) it is determined that the current video coding layer is the only layer in the bitstream (e.g., sps_video_parameter_set_id is equal to 0).

[0218] It should be noted that the bit stream may be obtained by a wireless network or a wired network: the bit stream may be 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, microwave, WIFI, Bluetooth, LTE, or 5G.

[0219] A bitstream may be a sequence of bits in the form of a Network Abstraction Layer (NAL) unit stream or a byte stream, forming a representation of a sequence of access units (AUs) that form one or more Coded Video Sequences (CVSs).

[0220] In a particular example, a bitstream format specifies the relationship between Network Abstraction Layer (NAL) unit streams and byte streams, both of which are referred to as bitstreams.

[0221] A bitstream can be in one of two formats: a NAL unit stream format or a byte stream format. The NAL unit stream format is conceptually the more "basic" type. It contains a sequence of syntactic structures called NAL units, arranged in decoding order. Constraints are imposed on the decoding order (and content) of the NAL units within a NAL unit stream.

[0222] A byte stream format can be constructed from the NAL unit stream format by arranging the NAL units in decoding order and prefixing each NAL unit with a start code prefix and zero or more zero-valued bytes to form a byte stream. The NAL unit stream format can be extracted from the byte stream format by searching for the location of a unique start code prefix pattern in the byte stream.

[0223] FIG. 10 shows a method for encoding a video bitstream implemented by an encoding device, the bitstream including data representing a current video coding layer, the method including step 1010 determining whether the current video coding layer is the only layer in the bitstream, and step 1020 using an identifier of a NAL unit of the current video coding layer as an identifier of the current video coding layer if it is determined that the current video coding layer is the only layer in the bitstream.

[0224] The above-mentioned methods can be implemented in a video decoding device or a video encoding device (producing a bitstream), respectively, as described below.

[0225] As shown in Figure 11, a video decoding apparatus 1100 provided herein according to an embodiment includes a decision unit 1110 and a prediction unit 1120. As shown in Figure 12, a video encoding apparatus 1200 provided herein according to an embodiment includes a decision unit 1210 and a prediction unit 1220.

[0226] The determining unit 1110 included in the video decoding device 1100 shown in FIG. 11 is configured to determine whether the current video coding layer is the only layer in the bitstream. The prediction unit 1120 included in the video decoding device 1100 shown in FIG. 11 is configured to use an identifier of the NAL unit of the current video coding layer (e.g., nuh_layer_id) as an identifier of the current video coding layer (e.g., vps_layer_id) if (e.g., only if) the current video coding layer is the only layer in the bitstream (e.g., sps_video_parameter_set_id is equal to 0). In It has been made.

[0227] The determining unit 1210 included in the video encoding apparatus 1200 shown in Figure 12 is configured to determine whether the current video coding layer is the only layer in the bitstream. The predicting unit 1220 included in the video encoding apparatus 1200 shown in Figure 12 is configured to use an identifier of a NAL unit of the current video coding layer as an identifier of the current video coding layer if it determines that the current video coding layer is the only layer in the bitstream.

[0228] The video decoding device 1100 shown in FIG. 11 may be or may be configured by the decoder 30 shown in FIG. 1A, FIG. 1B, and FIG. 3, and the video decoder 3206 shown in FIG. 14. Device1100 may be configured by the video coding device 400 shown in FIG. 4, the apparatus 500 shown in FIG. 5, and the terminal device 3106 shown in FIG. 13. Device 1200 may be, or may be configured by, the encoder 20 shown in FIGS. 1A, 1B, and 3. Device 1200 may be composed of the video coding device 400 shown in FIG. 4, the apparatus 500 shown in FIG. 5, and the capture device 3102 shown in FIG.

[0229] Hereinafter, application examples of the encoding method and the decoding method shown in the above embodiment and a system using them will be described.

[0230] 13 is a block diagram showing a content supply system 3100 for realizing a content distribution service. The content supply system 3100 includes a capture device 3102, a terminal device 3106, and optionally a display 3126. The capture device 3102 communicates with the terminal device 3106 via 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, WIFI, Ethernet, cable, wireless (3G / 4G / 5G), USB, or any type of combination thereof, etc.

[0231] The capture device 3102 may generate data and encode the data by the encoding method as shown in the above embodiment. Alternatively, the capture device 3102 may deliver the data to a streaming server (not shown), which encodes the data and transmits the encoded data to the terminal device 3106. The capture device 3102 may include, but is not limited to, a camera, a smartphone or pad, 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 above-mentioned source device 12. If the data includes video, the video encoder 20 included in the capture device 3102 may actually perform the video encoding process. If the data includes audio (i.e., voice), the audio encoder included in the capture device 3102 may actually perform the audio encoding process. In some practical scenarios, the capture device 3102 delivers the encoded video data and the audio data by multiplexing them together. In other practical scenarios, for example in a video conferencing system, the encoded audio data and the encoded video data are not multiplexed. The capture device 3102 delivers the encoded audio data and the encoded video data separately to the terminal device 3106 .

[0232] In the content supply system 3100, a terminal device 3106receives and plays the encoded data. The terminal device 3106 may be a device with data receiving and recovering capabilities, such as a smartphone or pad 3108, a computer or laptop 3110, a network video recorder (NVR) / digital video recorder (DVR) 3112, a television 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, or one that can decode the encoded data described above. For example, the terminal device 3106 may include the destination device 14 described above. If the encoded data includes video, the video decoder 30 included in the terminal device is prioritized to perform video decoding. If the encoded data includes audio, the audio decoder included in the terminal device is prioritized to perform audio decoding processing.

[0233] For example, in the case of a terminal device with a display, such as a smartphone or pad 3108, a computer or laptop 3110, a network video recorder (NVR) / digital video recorder (DVR) 3112, a television 3114, a personal digital assistant (PDA) 3122, or an in-vehicle device 3124, the terminal device can provide the decoded data to its display. In the case of a terminal device without a display, such as an STB 3116, a video conferencing system 3118, or a video surveillance system 3120, it contacts an external display 3126 to receive and display the decoded data.

[0234] If each device in the system performs encoding or decoding, it can use a picture encoding device or a picture decoding device as shown in the above embodiment.

[0235] 14 is a diagram showing the structure of an example of a terminal device 3106. After the terminal device 3106 receives a stream from the capture device 3102, the protocol progression unit 3202 analyzes the transmission protocol of the stream. The protocol includes, but is not limited to, Real Time Streaming Protocol (RTSP), Hypertext Transfer Protocol (HTTP), HTTP Live Streaming Protocol (HLS), MPEG-DASH, Real Time Transport Protocol (RTP), Real Time Messaging Protocol (RTMP), or any kind of combination thereof.

[0236] After the protocol proceeding 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 mentioned above, for example, in some practical scenarios, for example in a video conferencing system, the encoded audio data and the encoded video data are not multiplexed. In this situation, the encoded data is transmitted to the video decoder 3206 and the audio decoder 3208 without passing through the demultiplexing unit 3204.

[0237] Through the demultiplexing process, a video elementary stream (ES), an audio ES, and optionally a subtitle are generated. The video decoder 3206, including the video decoder 30 described in the above embodiment, decodes the video ES by a decoding method as shown in the above embodiment to generate a video frame, and supplies the data to the synchronization unit 3212. The audio decoder 3208 decodes the audio ES to generate an audio frame, and supplies the data to the synchronization unit 3212. Alternatively, the video frame may be stored in a buffer (not shown in FIG. 14) before supplying it to the synchronization unit 3212. Similarly, the audio frame may be stored in a buffer (not shown in FIG. 14) before supplying it to the synchronization unit 3212.

[0238] The synchronization unit 3212 synchronizes the video and audio frames and transmits the video / audio to the video / audio display. 3216 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 the coded audio and visual data and for the delivery of the data stream itself.

[0239] The subtitle decoder 3210 decodes the subtitles, if any are included in the stream, synchronizes them with the video and audio frames, and provides the video / audio / subtitles to the video / audio / subtitle display 3216 .

[0240] It should be noted that the present invention is not limited to the above system, and the picture encoding device or the picture decoding device in the above embodiment can be incorporated into other systems, for example, an automobile system.

[0241] Mathematical Operators The arithmetic 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 additional operations such as exponentiation and real value division are defined. The numbering and counting conventions generally start from 0, e.g., "first" corresponds to the 0th, "second" corresponds to the 1st, etc.

[0242] Arithmetic Operators The following arithmetic operators are defined as follows:

[0243] [Table 3]

[0244] Logical Operators The following logical operators are defined as follows: x && y Boolean logic "and" of x and y x||y Boolean logic "or" of x and y ! Boolean logic "not" x ? y : zIf x is TRUE or not equal to 0, evaluates to the value of y, otherwise it evaluates to the value of z.

[0245] Relational Operators The following relational operators are defined as follows: > Greater than >= Greater than or equal to < Less than <= Less than or equal = = equal to != not equal

[0246] When a relational operator is applied to a syntax element or variable that has been 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 equal to any other value.

[0247] Bitwise Operators The following bitwise operators are defined as follows: & Bitwise "and". When operating on an integer argument, the two's complement representation of the integer value is operated on. When operating on a binary argument that has fewer bits than the other argument, the shorter argument is extended by appending significant bits equal to 0. Bitwise "or". When operating on an integer argument, the two's complement representation of the integer value is operated on. When operating on a binary argument that has fewer bits than the other argument, the shorter argument is extended by appending significant bits equal to 0. ^ Bitwise "exclusive or". When operating on integer arguments, the two's complement representation of the integer value is operated on. When operating on a binary argument that has fewer bits than the other argument, the shorter argument is extended by appending significant bits equal to 0. Arithmetic right shift of the two's complement integer representation of x by the binary digits x >> yy. This function is defined only for nonnegative 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. Arithmetic left shift of the two's complement integer representation of x by the binary digits x << yy. This function is defined only for nonnegative integer values ​​of y. The bit shifted into the least significant bit (LSB) as a result of the left shift has value equal to 0.

[0248] Assignment Operators Next Assignment The operators are defined as follows: = assignment operator ++ Increment, i.e., x++ is equivalent to x=x+1, and when used in an array index, evaluates to the value of the variable before the increment operation. -- Decrement, i.e., x- -- is equivalent to x=x-1, and when used in an array index, evaluates to the value of the variable before the decrement operation. += Increment by the specified amount, i.e., x+=3 is equal to x=x+3 and x+=(-3) is equal to x=x+(-3). -= Decrement by the specified amount, i.e. x-=3 is equal to x=x-3 and x-=(-3) is equal to x=x-(-3).

[0249] Range Notation To specify a range of values, the following notation is used: x = y..zx takes integer values ​​between y and z, inclusive, where x, y, and z are integers and z is greater than y.

[0250] Mathematical Functions The following mathematical functions are defined:

[0251]

number

[0252] Asin(x) is the trigonometric arcsine function that operates on an argument x in the range -1.0 to 1.0, inclusive, and has an output value in radians in the range -π÷2 to π÷2, inclusive. Atan(x) is the trigonometric arctangent function operated on the argument x, with output values ​​in the range -π÷2 to π÷2, inclusive, in radians.

[0253]

number

[0254] Ceil(x) The smallest integer greater than or equal to x. Clip1 Y (x)=Clip3(0,(1 < <BitDepth Y )-1,x) Clip1 C (x)=Clip3(0,(1 < <BitDepth C )-1,x)

[0255]

number

[0256] Cos(x) The trigonometric cosine function of the argument x, calculated in radians. Floor(x) The largest integer less than or equal to x.

[0257]

number

[0258] Ln(x) The natural logarithm of x (logarithm to the base e, where e is the constant base of the natural logarithm, 2.718 281 828...). Log2(x) The base 2 logarithm of x. Log10(x) The base 10 logarithm of x.

[0259]

number

[0260] Round(x)=Sign(x)*Floor(Abs(x)+0.5)

[0261]

number

[0262] Sin(x) The trigonometric sine function of the argument x in radians.

[0263]

number

[0264] Swap(x, y)=(y, x) Tan(x) The trigonometric tangent function of the argument x in radians.

[0265] Action Priority If the precedence of an expression is not stated explicitly using parentheses, the following rules apply: - Operations with higher precedence are evaluated before operations with lower precedence. - Operations of equal precedence are evaluated in order from left to right.

[0266] The following table lists the precedence of operations from highest to lowest, with higher positions in the table indicating higher precedence.

[0267] For operators that are also used in the C programming language, the precedence used herein is the same as that used in the C programming language.

[0268] [Table 4]

[0269] Text description of logical operations In the text, a statement of logical operations written mathematically in the following form: if( condition 0 ) statement 0 else if( condition 1 ) statement 1 ... else / * informative remark on remaining condition * / statement n can be written as follows: ... as follows / ... the following applies: - If condition 0, statement 0 - Otherwise, if condition 1, statement 1 - ... - Otherwise (informative remark on remaining condition), statement n Each "If ... Otherwise, if ... Otherwise, ..." statement in the text begins with "... as follows" or "... the following applies" and is immediately followed by "If ...". The last condition in an "If ... Otherwise, if ... Otherwise, ..." is always "Otherwise, ...". Interleaved "If ... Otherwise, if ... Otherwise, ..." statements can be identified by matching the "... as follows" or "... the following applies" with the trailing "Otherwise, ...".

[0270] In the text, a statement of logical operations written mathematically in the following form: if( condition 0a && condition 0b ) statement 0 else if( condition 1a || condition 1b ) statement 1 ... else statement n can be written as follows: ... as follows / ... the following applies: - If all of the following conditions are true, statement 0: - condition 0a - condition 0b - Otherwise, if one or more of the following conditions are true, statement 1: - condition 1a - condition 1b - ... - Otherwise, statement n

[0271] In the text, a statement of logical operations written mathematically in the following form: if( condition 0 ) statement 0 if( condition 1 ) statement 1 can be written as follows: When condition 0, statement 0 When condition 1, statement 1.

[0272] Although the embodiments of the present invention have been described mainly based on video coding, it should be noted that the coding system 10, encoder 20 and decoder 30 (and corresponding system 10) embodiments, as well as other embodiments described herein, may also be configured for still image processing or coding, i.e., processing or coding of individual pictures, independent of preceding or successive pictures as in video coding. In general, only the inter prediction units 244 (encoder) and 344 (decoder) may not be available when picture processing coding is limited to a single picture 17. All other functions (also called tools or techniques) of the video encoder 20 and video decoder 30 may be equally used for still image processing, e.g., residual calculation 204 / 304, transform 206, quantization 208, inverse quantization 210 / 310, (inverse) transform 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.

[0273] The embodiments, e.g., of the encoder 20 and the decoder 30, and the functions described herein with respect to the encoder 20 and the decoder 30, can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on a computer-readable medium or transmitted as one or more instructions or codes 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 any medium that facilitates the transfer of a computer program from one place to another, e.g., according to a communication protocol. Thus, the computer-readable medium may generally correspond to (1) a tangible computer-readable storage medium that is non-transitory, or (2) a communication medium, such as a signal or carrier wave. The data storage medium may be any available medium that can be accessed by one or more computers or one or more processors to retrieve instructions, code, and / or data structures for implementing the techniques described in this disclosure. The computer program product may include a computer-readable medium.

[0274] By way of example, and not limitation, such computer-readable storage media may include 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 that can be accessed by a computer. Moreover, all connections are properly referred to as computer-readable media. 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, microwave, etc., the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, microwave, etc., are included in the definition of media. However, it should be understood that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transitory media, but instead cover non-transitory, tangible storage media. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray® disc, where disks typically reproduce data magnetically, while discs reproduce data optically using a laser. Combinations of the above should also be included within the scope of computer readable media.

[0275] The instructions can be written to one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), or field-programmable gateThe encoding and decoding techniques may be implemented by one or more processors, such as FPGAs, FPGA arrays, or other equivalent integrated or discrete logic circuits. Thus, the term "processor" as used herein may refer to any of the aforementioned structures, or any other structure suitable for implementing the techniques described herein. Furthermore, in some aspects, the functionality described herein may be provided within dedicated hardware and / or software modules configured for encoding and decoding, or may be incorporated into a combined codec. Furthermore, these techniques may be implemented entirely in one or more circuits or logic elements.

[0276] The techniques of the present disclosure may be implemented in a wide variety of devices or apparatuses, including wireless handsets, integrated circuits (ICs), or sets of ICs (e.g., chipsets). In this disclosure, various components, modules, or units are described to highlight functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require realization by different hardware units. Rather, as described above, the various units may be combined into a codec hardware unit or may be provided by a collection of interoperable hardware units including one or more processors as described above, together with appropriate software and / or firmware.

[0277] In particular, the following ten additional embodiments are also provided herein, listed as Embodiments 1-10.

[0278] 1. An aspect of a method for decoding a video or picture bitstream implemented by a decoding device, the bitstream including data representing a current video coding layer, the method including: if a syntax element specifying an identifier of the current video coding layer (e.g., vps_layer_id[0]) is not present in the bitstream (e.g., no VPS is present), using an identifier of a sequence parameter set in the bitstream as an identifier of the current video coding layer; and predicting a current slice of the current video coding layer using the identifier of the current video coding layer.

[0279] 2. An aspect of the method of aspect 1, wherein the step of using an identifier of a sequence parameter set in the bitstream as an identifier of the current video coding layer is to construct one or more reference picture lists for a current slice of the current video coding layer, and the step of predicting the current slice of the current video coding layer using the identifier of the current video coding layer includes predicting the current slice using the one or more reference picture lists.

[0280] 3. An aspect of a method for decoding a video or picture bitstream implemented by a decoding device, the bitstream including data representing a current video coding layer, the method including: if a syntax element specifying an identifier of the current video coding layer (e.g., vps_layer_id[0]) is not present in the bitstream (e.g., no VPS is present), using an identifier of a NAL unit of the current video coding layer as an identifier of the current video coding layer; and predicting a current slice of the current video coding layer using the identifier of the current video coding layer.

[0281] 4. An aspect of the method of aspect 3, wherein the step of using an identifier of the NAL unit of the current video coding layer as an identifier of the current video coding layer is constructing one or more reference picture lists for a current slice of the current video coding layer, and the step of predicting the current slice of the current video coding layer using the identifier of the current video coding layer includes predicting the current slice using the one or more reference picture lists.

[0282] 5. An embodiment of the method of embodiment 3 or 4, wherein the NAL unit of the current video coding layer is the first non-VCL NAL unit or the first VCL NAL unit of the current video coding layer present in the bitstream.

[0283] 6. An embodiment of the method of embodiment 3 or 4, wherein the NAL unit of the current video coding layer is any one of the NAL units of the current video coding layer present in the bitstream.

[0284] 7. An embodiment of a decoder (30) including processing circuitry for performing a method according to any one of embodiments 1 to 6.

[0285] 8. An embodiment of a computer program product comprising program code for, when executed on a computer or processor, performing a method according to any one of embodiments 1 to 6 above.

[0286] 9. An aspect of a decoder including one or more processors and a non-transitory computer-readable storage medium coupled to the processors and storing programming for execution by the processors, the programming, when executed by the processors, configuring the decoder to perform a method according to any one of aspects 1 to 6 above.

[0287] 10. An embodiment of a non-transitory computer readable medium carrying program code that, when executed by a computing device, causes the computing device to perform the method of any one of embodiments 1 to 6 above. [Explanation of symbols]

[0288] 10 Coding Systems 10. Video Coding System 10. Short Coding System 12 Source Device 13 Communication Channels 14 Destination Device 16 Picture Source 17 Picture or Picture Data 17 Raw Picture or Raw Picture Data 18 Preprocessor (or Preprocessing Unit) 18 Picture Preprocessor 19 Preprocessed Pictures 19 Preprocessed Picture Data 20 Video Encoder 20 Short Encoder 21 Encoded picture data 21 Encoded bitstream 22 Communication interface or communication unit 28 Communication Interface or Communication Unit 30 Decoder 30 Video Decoder 30 Short Decoder 31 Decoded picture data 31 Decoded Picture 32 Post Processor 32 Post Processing Unit 33 Post-Processed Picture Data 33 Post-processed pictures 34 Display Devices 201 Input 201 Input Interface 203 Picture Block 204 Residual Calculation Unit 205 Residual Blocks 205 Residual 206 Conversion Processing Unit 207 Conversion Factors 208 Quantization Units 209 Quantized Coefficients 209 Quantized Transform Coefficients 209 Quantized Residual Coefficients 210 Inverse Quantization Unit 211 Unquantized Coefficients 212 Inverse Transformation Processing Unit 213 Reconstructed Residual Blocks 213 Conversion Block 214 Reconstruction Unit 214 Adder or Summer 215 reconstructed blocks 216 Buffers 220 Loop Filter Unit 220 Loop Filter 221 Filtered Blocks 221 Filtered Reconstruction Blocks 230 Decoded Picture Buffer (DPB) 231 Decoded Picture 244 Inter Prediction Units 254 intra prediction units 260 Mode Selection Unit 262 Partitioning Unit 265 predicted blocks 265 Intra Prediction Blocks 265 Predictors 266 Syntax Elements 270 Entropy Encoding Units 272 Output 272 Output Interface 304 Entropy Decoding Unit 309 Quantized Coefficients 310 Inverse Quantization Unit 311 Conversion Factors 311 Unquantized Coefficients 312 Inverse Transformation Processing Unit 313 Conversion Block 313 Reconstructed Residual Blocks 314 Reconstruction Unit 314 Analog Adder 315 Reconstructed Blocks 320 Loop Filter 320 Loop Filter Unit 321 Filtered Blocks 321 Decoded Video Block 330 Decoded Picture Buffer (DBP) 331 Decoded Picture 344 Inter Prediction Units 354 intra prediction units 360 mode application unit 365 predicted blocks 400 Video Coding Device 410 Input Port 420 Receiver Unit (Rx) 430 Central Processing Unit (CPU) 430 Processor 440 Transmitter Unit (Tx) 450 output ports 460 Memory 470 Coding Module 500 devices 502 processor 504 Memory 506 Code and Data 508 Operating Systems 510 Application Program 512 Bus 514 Secondary Storage 518 Display 1100 Video Decoding Device 1110 Decision Unit 1120 prediction units 1200 Video Encoding Device 1210 Decision Unit 1220 prediction units 3100 Contents Supply System 3102 Capture Device 3104 Communication Links 3106 Terminal Device 3108 Smartphone or Pad 3110 Computer or Laptop 3112 Network Video Recorder (NVR) / Digital Video Recorder (DVR) 3114 Television 3116 Set-top box (STB) 3118 Video Conference System 3120 Video Surveillance System 3122 Personal digital assistant (PDA) 3124 In-vehicle devices 3126 Display 3126 External Display 3202 Protocol Progression Unit 3204 Demultiplexing Unit 3206 Video Decoder 3208 Audio Decoder 3210 Subtitle Decoder 3212 Synchronous Unit 3214 Video / Audio Display 3216 Video / Audio / Subtitle Display

Claims

1. 1. A method of decoding a video or picture bitstream implemented by a decoding device, the bitstream including data representing a current video coding layer, the method comprising: determining that the current video coding layer is the only layer in the bitstream if no video parameter set (VPS) is present in the bitstream; if it is determined that the current video coding layer is the only layer in the bitstream, using a layer identifier nuh_layer_id of a NAL unit of the current video coding layer indicated outside the VPS as an identifier vps_layer_id of the current video coding layer; A method comprising:

2. The method comprises: The method of claim 1 , further comprising predicting a current slice of the current video coding layer using the identifier of the current video coding layer.

3. The method comprises: The method of claim 1 or 2, further comprising: if it is determined that the bitstream includes multiple layers, obtaining the identifier of the current video coding layer by parsing the bitstream.

4. the identifier of the current video coding layer is used to construct one or more reference picture lists for a current slice of the current video coding layer; 4. The method of claim 1, wherein predicting the current slice of the current video coding layer using the identifier of the current video coding layer comprises predicting the current slice using the one or more reference picture lists.

5. The method according to claim 1 , wherein the NAL unit of the current video coding layer is a VCL NAL unit of the current video coding layer present in the bitstream.

6. The method of claim 5 , wherein the VCL NAL unit of the current video coding layer is a VCL NAL unit of any one of the current video coding layers present in the bitstream.

7. 1. A method of encoding a video or picture bitstream implemented by an encoding device, the bitstream including data representing a current video coding layer, the method comprising: determining that the current video coding layer is the only layer in the bitstream if no video parameter set (VPS) is present in the bitstream; if it is determined that the current video coding layer is the only layer in the bitstream, using a layer identifier nuh_layer_id of a NAL unit of the current video coding layer indicated outside the VPS as an identifier vps_layer_id of the current video coding layer; A method comprising:

8. The method comprises: The method of claim 7 , further comprising predicting a current slice of the current video coding layer using the identifier of the current video coding layer.

9. The method comprises: The method of claim 7 or 8, further comprising the step of encoding the identifier of the current video coding layer into the bitstream if it is determined that the bitstream includes multiple layers.

10. using the layer identifier of the NAL unit of the current video coding layer as the identifier of the current video coding layer comprises constructing one or more reference picture lists of a current slice of the current video coding layer; 10. The method of claim 7, wherein predicting the current slice of the current video coding layer using the identifier of the current video coding layer comprises predicting the current slice using the one or more reference picture lists.

11. The method according to claim 7 , wherein the NAL unit of the current video coding layer is a VCL NAL unit of the current video coding layer present in the bitstream.

12. The method of claim 11 , wherein the VCL NAL unit of the current video coding layer is a VCL NAL unit of any one of the current video coding layers present in the bitstream.

13. A coding device comprising processing circuitry for performing the method of any one of claims 1 to 6.

14. A coding device comprising processing circuitry for performing the method of any one of claims 7 to 12.

15. A computer program comprising a program code for performing the method according to any one of claims 1 to 6, when the computer program is run on a computer or processor.

16. A computer program comprising a program code for performing the method according to any one of claims 7 to 12, when the computer program is run on a computer or processor.

17. 1. A coding device comprising: one or more processors; a non-transitory computer-readable storage medium coupled to the one or more processors and storing programming for execution by the one or more processors; The programming, when executed by the one or more processors, configures the coding device to perform the method of any one of claims 1 to 6.

18. 1. A coding device comprising: one or more processors; a non-transitory computer-readable storage medium coupled to the one or more processors and storing programming for execution by the one or more processors; A coding device, the programming, when executed by the one or more processors, configuring the coding device to perform the method of any one of claims 7 to 12.

19. A non-transitory computer readable storage medium carrying program code which, when executed by a computing device, causes the computing device to perform the method of any one of claims 1 to 6.

20. A non-transitory computer readable storage medium carrying program code which, when executed by a computing device, causes the computing device to perform the method of any one of claims 7 to 12.

21. 1. An apparatus for decoding a video bitstream, comprising: a determining unit configured to determine that a current video coding layer is the only layer in the bitstream if no video parameter set (VPS) is present in the bitstream; a prediction unit configured to use a layer identifier nuh_layer_id of a NAL unit of the current video coding layer indicated outside the VPS as the identifier vps_layer_id of the current video coding layer when it is determined that the current video coding layer is the only layer in the bitstream; 13. An apparatus comprising:

22. 1. An apparatus for encoding a video bitstream, comprising: a determining unit configured to determine that a current video coding layer is the only layer in the bitstream if no video parameter set (VPS) is present in the bitstream; a prediction unit configured to use a layer identifier nuh_layer_id of a NAL unit of the current video coding layer indicated outside the VPS as the identifier vps_layer_id of the current video coding layer when it is determined that the current video coding layer is the only layer in the bitstream; 13. An apparatus comprising:

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