Method for decoding video information, method for encoding video information, method for storing a bitstream of video information, and method for transmitting a bitstream of video information

Abstract

A method for decoding video information according to one aspect of the present disclosure may include acquiring video information including supplemental enhancement information (SEI) processing order information including a processing order for a group of SEI message types, and determining a processing order for the SEI message type group based on the SEI processing order information. The SEI processing order information may include payload type information indicating a type of SEI message, prefix presence information indicating whether prefix information for the SEI message is present, and processing order information indicating a processing order according to the SEI message type. The SEI processing order information may further include parallel processing capability information indicating whether at least two SEI messages having the same processing order are invoked in parallel.

Description

[Technical Field]

[0001] The present disclosure relates to methods for decoding video information, encoding video information, storing a bitstream of video information, and / or transmitting a bitstream of video information. [Background technology]

[0002] Recently, demand for high-resolution, high-quality images, such as HD (High Definition) images and UHD (Ultra High Definition) images, has been increasing in various fields. As image data becomes higher in resolution and quality, the amount of information or bits to be transmitted increases relatively compared to conventional image data. The increase in the amount of information or bits to be transmitted results in an increase in transmission costs and storage costs.

[0003] This requires highly efficient image compression techniques for effectively transmitting, storing, and reproducing high-resolution, high-quality image information. Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure seeks to provide an encoding / decoding method and / or apparatus with improved encoding / decoding efficiency.

[0005] This disclosure seeks to provide a method for supporting parallel grouping of SEIs in an SEI processing order SEI message for a coded video bitstream.

[0006] The present disclosure seeks to utilize a flag indicating whether parallel invocation of SEI messages with the same processing order is preferred to support parallel grouping of SEIs.

[0007] The present disclosure aims to provide a method and / or a computer-readable recording medium for storing a bitstream generated by the encoding method according to the present disclosure.

[0008] The present disclosure seeks to provide a method and / or apparatus for transmitting a bitstream generated by an encoding method according to the present disclosure.

[0009] The technical problems to be achieved by the present disclosure are not limited to the technical problems described above, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the following description. [Means for solving the problem]

[0010] A method for decoding video information according to one aspect of the present disclosure may include acquiring video information including SEI (supplemental enhancement information) processing order information including a processing order for a group of SEI message types, and determining a processing order for the SEI message type group based on the SEI processing order information. The SEI processing order information may include payload type information indicating a type of SEI message, prefix presence information indicating whether prefix information for the SEI message is present, and processing order information indicating a processing order according to the SEI message type. The SEI processing order information may further include parallel processing capability information indicating whether at least two SEI messages having the same processing order are invoked in parallel.

[0011] According to one aspect of the present disclosure, an apparatus for decoding video information includes a memory and a processor coupled to the memory, wherein the processor acquires video information including supplemental enhancement information (SEI) processing order information including a processing order for a group of SEI message types, and determines a processing order for the SEI message type group based on the SEI processing order information. The SEI processing order information may include payload type information indicating a type of SEI message, prefix presence information indicating whether prefix information for the SEI message is present, and processing order information indicating a processing order according to the SEI message type. The SEI processing order information may further include parallel processing enable information indicating whether at least two SEI messages having the same processing order are invoked in parallel.

[0012] According to one aspect of the present disclosure, a method for encoding video information may include determining a processing order for a group of supplemental enhancement information (SEI) message types, generating SEI processing order information including the processing order for the group of SEI message types based on the processing order, and encoding the video information including the SEI processing order information. The SEI processing order information may include payload type information indicating a type of SEI message, prefix presence information indicating whether prefix information is present in the SEI message, and processing order information indicating a processing order according to the SEI message type. The SEI processing order information may further include parallel processing enable information indicating whether at least two SEI messages having the same processing order are invoked in parallel.

[0013] According to one aspect of the present disclosure, an apparatus for encoding video information includes a memory and a processor coupled to the memory, wherein the processor determines a processing order for a group of supplemental enhancement information (SEI) message types, generates SEI processing order information including the processing order for the group of SEI message types based on the processing order, and encodes the video information including the SEI processing order information. The SEI processing order information may include payload type information indicating a type of SEI message, prefix presence information indicating whether prefix information is present in the SEI message, and processing order information indicating a processing order according to the SEI message type. The SEI processing order information may further include parallel processing enable information indicating whether at least two SEI messages having the same processing order are invoked in parallel.

[0014] According to one aspect of the present disclosure, a method for storing a bitstream for video information may include acquiring video information including SEI (supplemental enhancement information) processing order information including a processing order for a group of SEI message types, and storing data including the bitstream of the video information in a computer-readable storage medium. The SEI processing order information may include payload type information indicating a type of SEI message, prefix presence information indicating whether prefix information of the SEI message is present, and processing order information indicating a processing order according to the type of the SEI message. The SEI processing order information may further include parallel processing capability information indicating whether at least two SEI messages having the same processing order are invoked in parallel.

[0015] According to one aspect of the present disclosure, a computer-readable storage medium stores data including a bitstream of video information, where the video information includes a processing order for a group of supplemental enhancement information (SEI) message types. The SEI processing order information may include payload type information indicating a type of SEI message, prefix presence information indicating whether prefix information is present in the SEI message, and processing order information indicating a processing order according to the type of the SEI message. The SEI processing order information may further include parallel processing capability information indicating whether at least two SEI messages having the same processing order are invoked in parallel.

[0016] According to one aspect of the present disclosure, a method for transmitting a bitstream of video information may include acquiring video information including SEI (supplemental enhancement information) processing order information including a processing order for a group of SEI message types, and transmitting data including the bitstream of the video information. The SEI processing order information may include payload type information indicating a type of SEI message, prefix presence information indicating whether prefix information is present in the SEI message, and processing order information indicating a processing order according to the type of the SEI message. The SEI processing order information may further include parallel processing capability information indicating whether at least two SEI messages having the same processing order are invoked in parallel.

[0017] According to one aspect of the present disclosure, an apparatus for transmitting a bitstream of video information may include a processor that acquires video information including SEI (supplemental enhancement information) processing order information, which includes a processing order for a group of SEI message types, and a transmitter that transmits data including the bitstream of the video information. The SEI processing order information may include payload type information indicating a type of SEI message, prefix presence information indicating whether prefix information of the SEI message is present, and processing order information indicating a processing order according to the type of the SEI message. The SEI processing order information may further include parallel processing enable information indicating whether at least two SEI messages having the same processing order are invoked in parallel.

[0018] In relation to the method / apparatus for decoding / encoding the video information, the method / storage medium for storing the bitstream of the video information, and the method / apparatus for transmitting the bitstream of the video information, a value of 1 for the parallel processing capability information may indicate that at least two SEI messages having the same processing order are invoked in parallel, and a value of 0 for the parallel processing capability information may indicate that the SEI messages are not invoked in parallel.

[0019] In the method / apparatus for decoding / encoding video information, the method / storage medium for storing the video information bitstream, and the method / apparatus for transmitting the video information bitstream, at least two SEI messages of the same type and having the same prefix information may have the same processing order, and at least two SEI messages of the same type and having no prefix information may have the same processing order.

[0020] In the method / apparatus for decoding / encoding video information, the method / storage medium for storing a bitstream of the video information, and the method / apparatus for transmitting a bitstream of the video information, the video information may further include processing order overlap information including position information of a specific SEI message within a processing order defined by the SEI processing order information. At least two SEI messages that have the same type, the same prefix information, and are not included in the processing order overlap information may have the same processing order. Also, at least two SEI messages that have the same type, no prefix information, and are not included in the processing order overlap information may have the same processing order.

[0021] The features briefly summarized above of the present disclosure are merely exemplary aspects of the detailed description of the present disclosure that follows and are not intended to limit the scope of the present disclosure. [Effects of the Invention]

[0022] According to the present disclosure, an encoding / decoding method and / or apparatus with improved encoding / decoding efficiency can be provided.

[0023] According to the present disclosure, parallel grouping can be supported, in which SEI messages with the same processing order are invoked in parallel.

[0024] According to the present disclosure, a method and / or a computer-readable recording medium for storing a bitstream generated by an encoding method according to the present disclosure may be provided.

[0025] According to the present disclosure, a method and / or apparatus for transmitting a bitstream generated by an encoding method according to the present disclosure may be provided.

[0026] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present disclosure pertains from the following description. [Brief explanation of the drawings]

[0027] [Figure 1] 1 illustrates schematically an example of a video / image coding system to which this document can be applied. [Figure 2] 1 is a diagram illustrating a schematic configuration of a video / image encoding device to which the present document can be applied. Hereinafter, the term "video encoding device" may include a video encoding device. [Figure 3] 1 is a diagram illustrating the configuration of a video / image decoding device to which the present document can be applied. [Figure 4] 1 shows an exemplary hierarchical structure for coded images / video. [Figure 5] 1 is a diagram illustrating an interleaved method for deriving a luma channel. [Figure 6] 1 is a diagram illustrating a method for decoding video information according to an embodiment of the present disclosure. [Figure 7] 1 is a diagram illustrating a method for encoding video information according to an embodiment of the present disclosure. [Figure 8] 1 illustrates an exemplary structural diagram of a content streaming system to which the embodiments of this document are applied. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present disclosure will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily implement the present disclosure. However, the present disclosure may be embodied in various different forms and is not limited to the embodiments described herein.

[0029] In describing the embodiments of the present disclosure, if it is determined that a detailed description of a known configuration or function may obscure the gist of the present disclosure, the detailed description thereof will be omitted. In addition, in the drawings, parts that are not related to the description of the present disclosure will be omitted, and similar parts will be designated by similar reference numerals.

[0030] In this disclosure, when a component is referred to as being "coupled," "coupled," or "connected" to another component, this includes not only a direct connection, but also an indirect connection where another component exists between them. Furthermore, when a component is referred to as "including" or "having" another component, this does not mean that the other component is excluded, but that the component can further include the other component, unless otherwise specified.

[0031] In this disclosure, terms such as "first" and "second" are used only to distinguish one component from another component, and do not limit the order or importance of the components unless otherwise specified. Therefore, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0032] In this disclosure, components that are distinguished from one another are used to clearly describe the characteristics of each component and do not necessarily mean that the components are separate. In other words, multiple components may be integrated into a single hardware or software unit, or a single component may be distributed into multiple hardware or software units. Therefore, even if not otherwise specified, such integrated or distributed embodiments are also included within the scope of this disclosure.

[0033] In this disclosure, the components described in various embodiments are not necessarily essential components, and some may be optional components. Therefore, an embodiment consisting of a subset of the components described in one embodiment is also within the scope of this disclosure. Furthermore, an embodiment including other components in addition to the components described in various embodiments is also within the scope of this disclosure.

[0034] This disclosure relates to video encoding and decoding. For example, the methods and embodiments disclosed in this document may be applied to methods disclosed in the versatile video coding (VVC) standard, the essential video coding (EVC) standard, the AOMedia Video 1 (AV1) standard, the second generation audio video coding standard (AVS2), or next generation video / image coding standards (e.g., H.267 or H.268).

[0035] This disclosure provides various embodiments related to video / image coding, and unless otherwise specified, the embodiments may be performed in combination with each other.

[0036] The present disclosure relates to image encoding and decoding, and terms used in this disclosure may have their ordinary meaning in the technical field to which the present disclosure belongs unless they are newly defined in this disclosure.

[0037] In this disclosure, a "picture" generally refers to a unit representing one image at a specific time period, and a slice / tile is a coding unit that constitutes part of a picture, and one picture may consist of one or more slices / tiles. A slice / tile may also include one or more coding tree units (CTUs). A picture may consist of one or more tile groups. A tile group may include one or more tiles. A brick may refer to a rectangular region of a CTU row of tiles within a picture. In this document, the terms tile group and slice may be used interchangeably. For example, in this document, a tile group / tile group header may be referred to as a slice / slice header.

[0038] In this disclosure, "pixel" or "pel" may refer to the smallest unit constituting one picture (or image). Also, "sample" may be used as a term corresponding to pixel. A sample may generally indicate a pixel or a pixel value, may indicate only a pixel / pixel value of a luma component, or may indicate only a pixel / pixel value of a chroma component.

[0039] In this disclosure, the term "unit" may refer to a basic unit of image processing. A unit may include at least one of a specific region of a picture and information related to that region. The term "unit" may be used interchangeably with terms such as "sample array," "block," or "area," depending on the situation. In general, an M×N block may include a set (or array) of samples or transform coefficients consisting of M columns and N rows.

[0040] In the present disclosure, a "current block" may refer to any one of a "current coding block," a "current coding unit," a "block to be coded," a "block to be decoded," or a "block to be processed." When prediction is performed, a "current block" may refer to a "current predicted block" or a "block to be predicted." When transformation (inverse transformation) / quantization (inverse quantization) is performed, a "current block" may refer to a "current transformed block" or a "block to be transformed." When filtering is performed, a "current block" may refer to a "block to be filtered."

[0041] Furthermore, in this disclosure, unless explicitly stated as a chroma block, the term "current block" may refer to a block including both a luma component block and a chroma component block, or to the "luma block of the current block." The luma component block of the current block may be expressed by explicitly including the term "luma block" or "current luma block." The chroma component block of the current block may be expressed by explicitly including the term "chroma block" or "current chroma block."

[0042] In the present disclosure, " / " and "," can be interpreted as "and / or." For example, "A / B" and "A, B" can be interpreted as "A and / or B." Also, "A / B / C" and "A, B, C" can mean "at least one of A, B, and / or C."

[0043] In this disclosure, "or" can be interpreted as "and / or." For example, "A or B" can mean 1) only "A," 2) only "B," or 3) "A and B." Alternatively, in this disclosure, "or" can mean "additionally or alternatively."

[0044] FIG. 1 illustrates schematically an example of a video / image coding system to which this document can be applied.

[0045] As shown in Figure 1, a video / image coding system may include a source device and a receiving device. The source device may transmit encoded video / image information or data to the receiving device in file or streaming form via a digital storage medium or a network.

[0046] The source device may comprise a video source, an encoding device, and a sending unit. The receiving device may comprise a receiving unit, a decoding device, and a renderer. The encoding device may be referred to as a video / video encoding device, and the decoding device may be referred to as a video / video decoding device. The transmitter may be included in the encoding device. The receiver may be included in the decoding device. The renderer may comprise a display unit, which may be a separate device or an external component.

[0047] A video source can acquire video / images through a video / image capture, synthesis, or generation process. A video source can include a video / image capture device and / or a video / image generation device. A video / image capture device can include, for example, one or more cameras, a video / image archive containing previously captured video / images, etc. A video / image generation device can include, for example, a computer, a tablet, a smartphone, etc., and can (electronically) generate video / images. For example, a virtual video / image can be generated via a computer, etc., in which case the video / image capture process can be replaced by a process in which related data is generated.

[0048] An encoding device can encode input video / images. The encoding device can perform a series of steps such as prediction, transformation, and quantization for compression and coding efficiency. The encoded data (encoded video / image information) can be output in the form of a bitstream.

[0049] The transmitter can transmit the encoded video / image information or data output in the form of a bitstream to a receiver in the receiving device via a digital storage medium or a network in the form of a file or streaming. The digital storage medium can include various storage media such as USB, SD, CD, DVD, Blu-ray (registered trademark: the same applies hereinafter), HDD, and SSD. The transmitter can include elements for generating a media file in a predetermined file format and elements for transmission via a broadcasting / communication network. The receiver can receive / extract the bitstream and transmit it to a decoding device.

[0050] The decoding device can decode the video / image by performing a series of steps such as inverse quantization, inverse transform, and prediction that correspond to the operations of the encoding device.

[0051] The renderer can render the decoded video / image, and the rendered video / image can be displayed via a display unit.

[0052] 2 is a diagram illustrating the configuration of a video / image encoding device to which this document can be applied. Hereinafter, the term "video encoding device" may include an image encoding device.

[0053] As shown in FIG. 2, the encoding device 200 may include an image partitioner 210, a predictor 220, a residual processor 230, an entropy encoder 240, an adder 250, a filter 260, and a memory 270. The predictor 220 may include an inter predictor 221 and an intra predictor 222. The residual processor 230 may include a transformer 232, a quantizer 233, a dequantizer 234, and an inverse transformer 235. The residual processor 230 may further include a subtractor 231. The adder 250 may be referred to as a reconstructor or a reconstructed block generator. The image dividing unit 210, the predicting unit 220, the residual processing unit 230, the entropy encoding unit 240, the adding unit 250, and the filtering unit 260 may be configured by one or more hardware components (e.g., an encoder chipset or a processor) depending on the embodiment. Also, the memory 270 may include a decoded picture buffer (DPB) and may be configured by a digital storage medium. The hardware components may further include the memory 270 as an internal / external component.

[0054] The image division unit 210 may divide an input image (or picture or frame) input to the encoding device 200 into one or more processing units. For example, the processing units may be called coding units (CUs). In this case, the coding units may be recursively divided from a coding tree unit (CTU) or a largest coding unit (LCU) according to a quad-tree, binary-tree, ternary-tree (QTBTTT) structure. For example, one coding unit may be divided into multiple coding units of deeper depths based on a quad-tree structure, a binary tree structure, and / or a ternary structure. In this case, for example, the quad-tree structure may be applied first, and then the binary tree structure and / or the ternary structure may be applied. Alternatively, the binary tree structure may be applied first. The coding procedure according to the present disclosure may be performed based on a final coding unit that is not further divided. In this case, the largest coding unit may be used as the final coding unit based on coding efficiency according to image characteristics, or the coding unit may be recursively divided into coding units of lower depths as needed, and a coding unit of an optimal size may be used as the final coding unit. Here, the coding procedure may include procedures such as prediction, transformation, and restoration, which will be described later. As another example, the processing unit may further include a prediction unit (PU) or a transform unit (TU). In this case, the prediction unit and the transform unit may each be divided or partitioned from the final coding unit.The prediction unit may be a unit of sample prediction, and the transform unit may be a unit for deriving transform coefficients and / or a unit for deriving a residual signal from the transform coefficients.

[0055] The term "unit" may be used interchangeably with terms such as "block" or "area." In general, an M×N block may refer to a set of samples or transform coefficients consisting of M columns and N rows. A sample generally refers to a pixel or a pixel value, and may refer to only a pixel / pixel value of a luma component, or may refer to only a pixel / pixel value of a chroma component. A sample can be used as a term corresponding to one pixel or pel of a picture (or image).

[0056] The subtraction unit 231 may subtract a prediction signal (predicted block, prediction sample, or prediction sample array) output from the prediction unit 220 from an input video signal (original block, original sample, or original sample array) to generate a residual signal (residual block, residual sample, or residual sample array), and the generated residual signal is transmitted to the conversion unit 232. The prediction unit 220 may perform prediction on a block to be processed (hereinafter, referred to as a current block) and generate a predicted block including prediction samples for the current block. The prediction unit 220 may determine whether intra prediction or inter prediction is applied in units of the current block or CU. The prediction unit may generate various information related to prediction, such as prediction mode information, and transmit the information to the entropy encoding unit 240, as will be described later in the description of each prediction mode. The prediction information may be encoded by the entropy encoding unit 240 and output in the form of a bitstream.

[0057] The intra prediction unit 222 may predict the current block by referring to samples in the current picture. The referenced samples may be located adjacent to or distant from the current block depending on the prediction mode. Prediction modes in intra prediction may include a plurality of non-directional modes and a plurality of directional modes. The non-directional modes may include, for example, DC mode and planar mode. The directional modes may include, for example, 33 directional prediction modes or 65 directional prediction modes depending on the granularity of the prediction direction. However, this is merely an example, and more or less directional prediction modes may be used depending on the settings. The intra prediction unit 222 may also determine the prediction mode to be applied to the current block using the prediction modes applied to neighboring blocks.

[0058] The inter prediction unit 221 may derive a predicted block for a current block based on a reference block (reference sample array) identified by a motion vector on a reference picture. In this case, to reduce the amount of motion information transmitted in inter prediction mode, the motion information may be predicted in units of blocks, sub-blocks, or samples based on the correlation of motion information between neighboring blocks and the current block. The motion information may include a motion vector and a reference picture index. The motion information may further include information on an inter prediction direction (such as L0 prediction, L1 prediction, or Bi prediction). In the case of inter prediction, the neighboring blocks may include spatial neighboring blocks present in the current picture and temporal neighboring blocks present in the reference picture. The reference picture including the reference block and the reference picture including the temporal neighboring block may be the same or different. The temporal neighboring block may be called a collocated reference block, a collocated CU (col CU), etc., and the reference picture including the temporal neighboring block may be called a collocated picture (colPic). For example, the inter predictor 221 may construct a motion information candidate list based on neighboring blocks and generate information indicating which candidate is used to derive a motion vector and / or a reference picture index for the current block. Inter prediction may be performed based on various prediction modes, and for example, in the case of a skip mode or a merge mode, the inter predictor 221 may use motion information of neighboring blocks as motion information of the current block. In the case of the skip mode, unlike the merge mode, a residual signal may not be transmitted.In the case of motion vector prediction (MVP) mode, the motion vector of the neighboring block can be used as a motion vector predictor, and the motion vector of the current block can be indicated by signaling the motion vector difference.

[0059] The predictor 220 may generate a prediction signal based on various prediction methods, which will be described later. For example, the predictor may apply intra prediction or inter prediction for prediction of a block, or may simultaneously apply intra prediction and inter prediction. This may be referred to as combined inter and intra prediction (CIIP). The predictor may also perform intra block copy (IBC) for prediction of a block. The intra block copy may be used for content image / video coding, such as games, such as screen content coding (SCC). IBC essentially performs prediction within a current picture, but may be similar to inter prediction in deriving a reference block within the current picture. That is, IBC may use at least one of the inter prediction techniques described in this document. Palette mode may be seen as an example of intra coding or intra prediction. When palette mode is applied, sample values ​​within a picture may be signaled based on information about a palette table and a palette index.

[0060] The prediction signal generated by the prediction unit 220 may be used to generate a restored signal and may also be used to generate a residual signal. The subtraction unit 231 may subtract the prediction signal (predicted block, predicted sample array) output from the prediction unit 220 from the input video signal (original block, original sample array) to generate a residual signal (residual signal, residual block, residual sample array). The generated residual signal may be transmitted to the conversion unit 232.

[0061] The transform unit 232 may generate transform coefficients by applying a transform technique to the residual signal. For example, the transform technique may include a discrete cosine transform (DCT), a discrete sine transform (DST), a graph-based transform (GBT), or a conditionally non-linear transform (CNT). Here, GBT refers to a transform obtained from a graph representing inter-pixel relationship information. CNT refers to a transform obtained based on a predicted signal generated using all previously reconstructed pixels. In addition, the transform process may be applied to pixel blocks having the same square size or to non-square blocks of variable size.

[0062] The quantization unit 233 quantizes the transform coefficients and transmits the quantized signal to the entropy encoding unit 240. The entropy encoding unit 240 encodes the quantized signal (information about the quantized transform coefficients) and outputs it as a bitstream. The information about the quantized transform coefficients may be referred to as residual information. The quantization unit 233 may rearrange the quantized transform coefficients in a block form into a one-dimensional vector form based on a coefficient scan order, and may generate information about the quantized transform coefficients based on the quantized transform coefficients in the one-dimensional vector form.

[0063] The entropy encoding unit 240 may perform various encoding methods, such as exponential Golomb, context-adaptive variable length coding (CAVLC), context-adaptive binary arithmetic coding (CABAC), etc. The entropy encoding unit 240 may encode information required for video / image restoration (e.g., values ​​of syntax elements) together with or separately from the quantized transform coefficients. The encoded information (e.g., encoded video / video information) may be transmitted or stored in the form of a bitstream in network abstraction layer (NAL) units. The video / video information may further include information on various parameter sets, such as an adaptation parameter set (APS), a picture parameter set (PPS), a sequence parameter set (SPS), or a video parameter set (VPS). The video / video information may also include general constraint information. The signaling / transmitted information and / or syntax elements described later in this document can be encoded through the encoding procedure described above and included in the bitstream, which can be transmitted over a network or stored on a digital storage medium.

[0064] Here, the network may include a broadcasting network and / or a communication network, and the digital storage medium may include various storage media such as a USB, SD, CD, DVD, Blu-ray, HDD, SSD, etc. A transmitter (not shown) for transmitting the signal output from the entropy encoding unit 240 and / or a storage unit (not shown) for storing the signal may be configured as an internal / external element of the encoding device 200, or the transmitter may be included in the entropy encoding unit 240.

[0065] The quantized transform coefficients output from the quantization unit 233 can be used to generate a prediction signal. For example, a residual signal (residual block or residual sample) can be reconstructed by applying inverse quantization and inverse transform to the quantized transform coefficients via the inverse quantization unit 234 and the inverse transform unit 235.

[0066] Meanwhile, luma mapping with chroma scaling (LMCS) can be applied during picture encoding and / or reconstruction.

[0067] The adder 155 may generate a reconstructed signal (reconstructed picture, reconstructed block, reconstructed sample, or reconstructed sample array) by adding the reconstructed residual signal to the prediction signal output from the prediction unit 220. When there is no residual for the current block, such as when skip mode is applied, the predicted block may be used as the reconstructed block. The generated reconstructed signal may be used for intra prediction of the next current block in the current picture, and may also be used for inter prediction of the next picture after filtering, as described below.

[0068] The filtering unit 260 may apply filtering to the reconstructed signal to improve subjective / objective image quality. For example, the filtering unit 260 may apply various filtering methods to the reconstructed picture to generate a modified reconstructed picture and store the modified reconstructed picture in the memory 270, specifically, in the DPB of the memory 270. The various filtering methods may include, for example, deblocking filtering, sample adaptive offset (SAO), an adaptive loop filter, a bilateral filter, etc. The filtering unit 260 may generate various information related to filtering and transmit it to the entropy encoding unit 240, as will be described later in connection with each filtering method. The filtering information may be encoded by the entropy encoding unit 240 and output in the form of a bitstream.

[0069] The modified reconstructed picture transmitted to the memory 270 can be used as a reference picture in the inter prediction unit 221. When inter prediction is applied through this, the encoding device can avoid prediction mismatch between the encoding device 100 and the decoding device, and can also improve coding efficiency.

[0070] The DPB of the memory 270 may store a modified reconstructed picture to be used as a reference picture in the inter predictor 221. The memory 270 may store motion information of a block from which motion information in the current picture is derived (or encoded) and / or motion information of a block in an already reconstructed picture. The stored motion information may be transmitted to the inter predictor 221 to be used as motion information of a spatially neighboring block or a temporally neighboring block. The memory 270 may store reconstructed samples of reconstructed blocks in the current picture and transmit them to the intra predictor 222.

[0071] FIG. 3 is a diagram illustrating the configuration of a video / image decoding device to which this document can be applied.

[0072] As shown in FIG. 3, the decoding device 300 may include an entropy decoder 310, a residual processor 320, a predictor 330, an adder 340, a filter 350, and a memory 360. The predictor 330 may include an inter-predictor 331 and an intra-predictor 332. The residual processor 320 may include a dequantizer 321 and an inverse transformer 322. The entropy decoder 310, residual processor 320, predictor 330, adder 340, and filter 350 may be configured as a single hardware component (e.g., a decoder chipset or processor) according to an embodiment. The memory 360 may include a decoded picture buffer (DPB) or may be configured as a digital storage medium. The hardware components may further include a memory 360 as an internal / external component.

[0073] When a bitstream including video / image information is input, the decoding device 300 can reconstruct an image corresponding to the process by which the video / image information was processed by the encoding device of FIG. 3. For example, the decoding device 300 can derive units / blocks based on block division-related information obtained from the bitstream. The decoding device 300 can perform decoding using the processing units applied by the encoding device. Therefore, the processing unit for decoding can be, for example, a coding unit, and the coding unit can be divided from a coding tree unit or a maximal coding unit according to a quad tree structure, a binary tree structure, and / or a ternary tree structure. One or more transform units can be derived from the coding unit. The reconstructed video signal decoded and output by the decoding device 300 can be played back via a playback device.

[0074] The decoding device 300 may receive a signal output from the encoding device of FIG. 3 in the form of a bitstream, and the received signal may be decoded via the entropy decoding unit 310. For example, the entropy decoding unit 310 may parse the bitstream to derive information (e.g., video / video information) necessary for video restoration (or picture restoration). The video / video information may further include information on various parameter sets, such as an adaptation parameter set (APS), a picture parameter set (PPS), a sequence parameter set (SPS), or a video parameter set (VPS). The video / video information may also include general constraint information. The decoding device may further decode pictures based on the information on the parameter sets and / or the general constraint information. Signaling / received information and / or syntax elements, which will be described later in this document, may be decoded via the decoding procedure and obtained from the bitstream. For example, the entropy decoding unit 310 may decode information in a bitstream based on a coding method such as Exponential-Golomb coding, CAVLC, or CABAC, and output values ​​of syntax elements required for image restoration and quantized values ​​of transform coefficients related to residuals. More specifically, the CABAC entropy decoding method receives bins corresponding to each syntax element in the bitstream, determines a context model using information on the syntax element to be decoded and decode information on adjacent and current blocks, or information on symbols / bins decoded in previous steps, predicts the occurrence probability of the bins based on the determined context model, and performs arithmetic decoding of the bins to generate symbols corresponding to the values ​​of each syntax element. In this case, after determining the context model, the CABAC entropy decoding method may update the context model using information on the decoded symbols / bins for the context model of the next symbol / bin.Among the information decoded by the entropy decoding unit 310, information related to prediction is provided to the prediction unit 330, and residual information entropy decoded by the entropy decoding unit 310, i.e., quantized transform coefficients and related parameter information, may be input to the inverse quantization unit 321. Among the information decoded by the entropy decoding unit 310, information related to filtering may be provided to the filtering unit 350. Meanwhile, a receiving unit (not shown) that receives a signal output from the encoding device may be further configured as an internal / external element of the decoding device 300, or the receiving unit may be a component of the entropy decoding unit 310. Meanwhile, the decoding device according to this document may be referred to as a video / image / picture decoding device, and the decoding device may be divided into an information decoder (video / image / picture information decoder) and a sample decoder (video / image / picture sample decoder). The information decoder may include the entropy decoding unit 310, and the sample decoder may include at least one of the inverse quantization unit 321, the inverse transform unit 322, the prediction unit 330, the addition unit 340, the filtering unit 350, and the memory 360.

[0075] The inverse quantization unit 321 may inverse quantize the quantized transform coefficients and output the transform coefficients. The inverse quantization unit 321 may rearrange the quantized transform coefficients in a two-dimensional block format. In this case, the rearrangement may be performed based on the coefficient scanning order performed in the encoding device. The inverse quantization unit 321 may inverse quantize the quantized transform coefficients using a quantization parameter (e.g., quantization step size information) to obtain transform coefficients.

[0076] The inverse transform unit 322 performs inverse transform on the transform coefficients to obtain a residual signal (residual block, residual sample array).

[0077] The predictor may generate a prediction signal based on various prediction methods, which will be described later. For example, the predictor may apply intra prediction or inter prediction for prediction of a block, or may simultaneously apply intra prediction and inter prediction. This may be referred to as combined inter and intra prediction (CIIP). The predictor may also perform intra block copy (IBC) for prediction of a block. The intra block copy may be used for content image / video coding, such as games, such as screen content coding (SCC). IBC basically performs prediction within a current picture, but may be performed similarly to inter prediction in deriving a reference block within the current picture. That is, IBC may utilize at least one of the inter prediction techniques described in this document. Palette mode may be considered an example of intra coding or intra prediction. Palette mode may be considered an example of intra coding or intra prediction. When palette mode is applied, sample values ​​within a picture may be signaled based on information related to a palette table and a palette index.

[0078] The intra prediction unit 331 can predict a current block by referring to samples in a current picture. The referenced samples can be located adjacent to or distant from the current block depending on the prediction mode. In intra prediction, prediction modes can include a plurality of non-directional modes and a plurality of directional modes. The intra prediction unit 331 can also determine a prediction mode to be applied to the current block using prediction modes applied to neighboring blocks.

[0079] The inter prediction unit 332 may derive a predicted block for the current block based on a reference block (reference sample array) identified by a motion vector on a reference picture. To reduce the amount of motion information transmitted in inter prediction mode, the motion information may be predicted in units of blocks, sub-blocks, or samples based on the correlation of motion information between neighboring blocks and the current block. The motion information may include a motion vector and a reference picture index. The motion information may further include information on the inter prediction direction (e.g., L0 prediction, L1 prediction, Bi prediction, etc.). In the case of inter prediction, the neighboring blocks may include spatial neighboring blocks in the current picture and temporal neighboring blocks in the reference picture. For example, the inter prediction unit 332 may construct a motion information candidate list based on the neighboring blocks and derive a motion vector and / or a reference picture index for the current block based on received candidate selection information. Inter prediction may be performed based on various prediction modes, and the prediction information may include information indicating the inter prediction mode for the current block.

[0080] The adder 340 may generate a reconstructed signal (reconstructed picture, reconstructed block, reconstructed sample array) by adding the obtained residual signal to the prediction signal (predicted block, predicted sample array) output from the prediction unit. When there is no residual for the current block to be processed, such as when skip mode is applied, the predicted block may be used as the reconstructed block. The adder 340 may be referred to as a reconstruction unit or a reconstructed block generator. The generated reconstructed signal may be used for intra prediction of the next current block to be processed in the current picture, may be output after filtering as described below, or may be used for inter prediction of the next picture.

[0081] Meanwhile, LMCS (luma mapping with chroma scaling) can be applied during the picture decoding process.

[0082] The filtering unit 350 may apply filtering to the reconstructed signal to improve subjective / objective image quality. For example, the filtering unit 350 may apply various filtering methods to the reconstructed picture to generate a modified reconstructed picture, and may transmit the modified reconstructed picture to the memory 360, specifically, to the DPB of the memory 360. The various filtering methods may include, for example, deblocking filtering, sample adaptive offset, an adaptive loop filter, a bilateral filter, etc.

[0083] The (modified) reconstructed picture stored in the DPB of the memory 360 can be used as a reference picture in the inter predictor 332. The memory 360 can store motion information of a block from which motion information in the current picture is derived (or decoded) and / or motion information of a block in an already reconstructed picture. The stored motion information can be transmitted to the inter predictor 332 to be used as motion information of a spatially neighboring block or a temporally neighboring block. The memory 360 can store reconstructed samples of reconstructed blocks in the current picture and transmit them to the intra predictor 331.

[0084] In this specification, the embodiments described for the filtering unit 260, inter prediction unit 221, and intra prediction unit 222 of the encoding device 200 may also be applied identically or correspondingly to the filtering unit 350, inter prediction unit 332, and intra prediction unit 331 of the decoding device 300, respectively.

[0085] FIG. 4 shows an exemplary hierarchical structure for coded images / video.

[0086] Referring to Figure 4, the coded image / video is divided into a VCL (video coding layer) that handles the image / video decoding process and itself, a lower system that transmits and stores the coded information, and a NAL (network abstraction layer) that exists between the VCL and the lower system and is responsible for network adaptation functions.

[0087] The VCL can generate VCL data including compressed video data (slice data), or can generate parameter sets including information such as a Picture Parameter Set (PPS), a Sequence Parameter Set (SPS), and a Video Parameter Set (VPS), or an SEI (Supplemental Enhancement Information) message that is additionally required for the video decoding process.

[0088] In NAL, NAL units can be generated by adding header information (NAL unit header) to RBSP (Raw Byte Sequence Payload) generated by VCL. In this case, RBSP refers to slice data, parameter sets, SEI messages, etc. generated by VCL. The NAL unit header can contain NAL unit type information identified by the RBSP data included in the corresponding NAL unit.

[0089] As shown in the drawing, NAL units can be classified into VCL NAL units and non-VCL NAL units according to the RBSP generated by the VCL. A VCL NAL unit can refer to a NAL unit containing information about a video (slice data), and a non-VCL NAL unit can refer to a NAL unit containing information necessary for decoding a video (parameter set or SEI message).

[0090] The VCL NAL unit and non-VCL NAL unit can be transmitted over a network with header information according to the data standard of the lower system. For example, the NAL unit can be transformed into a data format of a predetermined standard such as H.266 / VVC file format, RTP (Real-time Transport Protocol), TS (Transport Stream), etc. and transmitted over various networks.

[0091] As mentioned above, the NAL unit type of an NAL unit can be identified by the RBSP data structure included in the corresponding NAL unit, and information about such NAL unit type can be stored and signaled in the NAL unit header.

[0092] For example, NAL units can be broadly classified into VCL NAL unit types and non-VCL NAL unit types depending on whether the NAL unit contains information about a video (slice data). The VCL NAL unit types can be classified according to the nature and type of pictures included in the VCL NAL unit, and the non-VCL NAL unit types can be classified according to the type of parameter set.

[0093] The following is an example of a NAL unit type identified by the type of parameter set included in the non-VCL NAL unit type.

[0094] -APS (Adaptation Parameter Set) NAL unit: Type for NAL units including APS -DPS (Decoding Parameter Set) NAL unit: Type for NAL units containing DPS -VPS (Video Parameter Set) NAL unit: Type for NAL unit containing VPS -SPS (Sequence Parameter Set) NAL unit: Type for NAL unit including SPS -PPS (Picture Parameter Set) NAL unit: Type for NAL unit including PPS The above-mentioned NAL unit type has syntax information for the NAL unit type, and the syntax information can be stored in a NAL unit header and signaled. For example, the syntax information can be nal_unit_type, and the NAL unit type can be specified by the nal_unit_type value.

[0095] The slice header (slice header syntax, slice header information) can include information / parameters commonly applicable to the slices. The APS (APS syntax) or PPS (PPS syntax) can include information / parameters commonly applicable to one or more slices or pictures. The SPS (SPS syntax) can include information / parameters commonly applicable to one or more sequences. The VPS (VPS syntax) can include information / parameters commonly applicable to multiple layers. The DPS (DPS syntax) can include information / parameters commonly applicable to video in general. The DPS can include information / parameters related to concatenation of coded video sequences (CVSs). In this document, the term "High level syntax (HLS)" can include at least one of the APS syntax, PPS syntax, SPS syntax, VPS syntax, DPS syntax, picture header syntax, and slice header syntax.

[0096] In this document, image / video information encoded from an encoding device to a decoding device and signaled in the form of a bitstream may include not only intra-picture partitioning-related information, intra / inter prediction information, residual information, in-loop filtering information, etc., but also information included in the slice header, information included in the picture header, information included in the APS, information included in the PPS, information included in the SPS, information included in the VPS, and / or information included in the DPS. In addition, the image / video information may further include information of a NAL unit header.

[0097] In the following, the SEI messages relevant to the present invention will be described.

[0098] Large supplemental enhancement information message (Large SEI message) Table 1 shows an example of the high-capacity SEI message syntax.

[0099] [Table 1] Each large capacity SEI message includes variables that specify the type (payloadType) and size (payloadSize) of the large capacity SEI message payload. The derived large capacity SEI message payload size (payloadSize) is specified in bytes and MUST be equal to the number of RBSP bytes in the large capacity SEI message payload. Note that the NAL unit byte sequence containing the large capacity SEI message includes one or more emulation prevention bytes (represented by the emulation_prevention_three_byte syntax element). Because the payload size of a large capacity SEI message is specified in RBSP bytes, the amount of emulation prevention bytes is not included in the size (payloadSize) of the large capacity SEI payload.

[0100] lsei_position indicates whether the SEI message corresponds to PREFIX_SEI_NUT or SUFFIX_SEI_NUT. If the value of lsei_position is 0, it indicates that the SEI message is processed with PREFIX_SEI_NUT. If the value of lsei_position is 1, it indicates that the SEI message is processed with SUFFIX_SEI_NUT. The values ​​3 and 4 of lsei_position are reserved for future use and should be ignored.

[0101] lsei_relevance indicates the relevance of the SEI message to the target application. lsei_relevance ranges from 0 to 3, with 0 being the least relevant and 3 being the most relevant. Note that the relevance of an SEI message is an arbitrary decision, and its use must be specified by the target application.

[0102] lsei_reserved is reserved for future use and should be ignored.

[0103] lsei_payload_type_byte is the payload type byte of the large SEI message. payloadType=lsei_payload_type_byte. payload_size_16bits is the payload size in bits of the large SEI message. payloadSize=payload_size_16bits. A general post-processing filtering procedure using a Neural-Network Post-Filter The input to this procedure is the bitstream BitstreamToFilter and the output is the list of NNPF output pictures ListNnpfOutputPics.

[0104] First, BitstreamToFilter is decoded, and the list CroppedDecodedPictures is set to a list of cropped and decoded pictures in output order as a result of decoding BitstreamToFilter.

[0105] Second, the filtering process for one picture resides in CroppedDecodedPictures and is applied repeatedly to each cropped decoded picture for which one or more NNPFs are activated, in output order.

[0106] The order of pictures in ListNnpfOutputPics is the same as the output order.

[0107] A picture associated with a particular time instance may not appear more than once in ListNnpfOutputPics. If multiple NNPFs are active for a particular picture in CroppedDecodedPictures, and any of the NNPFs could be selected, but the selection is allowed to apply only one, then this constraint may apply regardless of which NNPF is selected to apply to the particular picture.

[0108] Filtering a single image using NNPF The filtering procedures described below reside in CroppedDecodedPictures and can be applied to each cropped and decoded picture (referred to as the current picture) for which one or more NNPFs are activated.

[0109] When applying the NNPF to the current picture, a filtered and / or interpolated picture is generated by the NNPF by applying the NNPF procedures specified in the semantics of the NNPFC SEI message to the current picture on a patch-by-patch basis.

[0110] When applying an NNPF to a current picture, the order of pictures generated by the NNPF is the output order by applying the NNPF stored in the output tensor of the NNPF.

[0111] If the applied NNPF is the last NNPF applied to the current picture, the pictures generated by the NNPF and output by the NNPF procedure may be included in ListNnpfOutputPics in the same order as the pictures are stored in the NNPF's output tensor.

[0112] Neural-network post-filter characteristics (NNPFC) The combinations in Table 2 show the NNPFC syntax structure.

[0113] [Table 2] JPEG2026505576000004.jpg206128JPEG2026505576000005.jpg206125The NNPFC SEI message can specify neural networks that can be used as post-processing filters. The use of specified post-processing filters (NNPFs) for a particular picture can be indicated using neural-network post-filter activation SEI messages. Here, "post-processing filter" and "post-filter" can have the same meaning.

[0114] To use such an SEI message, it may be necessary to define the following variables:

[0115] The input picture width and height in luma samples can be indicated by CroppedWidth and CroppedHeight, respectively.

[0116] The luma sample array CroppedYPic[idx] and chroma sample arrays CroppedCbPic[idx] and CroppedCrPic[idx] of the input picture with index idx in the range of -0 to numInputPics-1 may be used as input to the NNPF, if present.

[0117] -BitDepthY may indicate the bit depth for the luma sample array of the input picture.

[0118] -BitDepthC can indicate the bit depth of the chroma sample array (if any) of the input picture.

[0119] -ChromaFormatIdc may indicate a chroma format identifier.

[0120] If the value of -nnpfc_auxiliary_inp_idc is 1, the filtering strength control value array StrengthControlVal[idx] must contain real numbers in the range 0 to 1 for input pictures with index idx in the range 0 to numInputPics-1.

[0121] An input picture with index 0 may correspond to a picture for which the NNPF defined by the NNPFC SEI message is activated by the NNPFA SEI message. Input pictures with index i ranging from 0 to numInputPics-1 may precede an input picture with index i-1 in the output order.

[0122] The variables SubWidthC and SubHeightC can be derived from ChromaFormatIdc.

[0123] There can be more than one NNPFC SEI message for the same picture. If two or more NNPFC SEI messages with different nnpfc_id values ​​exist or are activated for the same picture, the two or more NNPFC SEI messages can have the same or different nnpfc_purpose and nnpfc_mode_idx values.

[0124] nnpfc_purpose can indicate the purpose of the NNPF as specified in Table 3.

[0125] [Table 3] Here, if (nnpfc_purpose & bitMask) is not 0, it can indicate that the NNPF has a purpose associated with the bitMask value in Table 3. If nnpfc_purpose is greater than 0 and (nnpfc_purpose & bitMask) is 0, the purpose associated with the bitMask value may not be applied to the NNPF. If nnpfc_purpose is 0, the NNPF can be used.

[0126] The nnpfc_purpose value MUST be present in the bitstream in the range 0 to 63. Values ​​64 to 65535 for nnpfc_purpose MAY be reserved for future use and MAY NOT be present in the bitstream. Decoders MUST ignore NNPFC SEI messages containing an npfc_purpose in the range 64 to 65535.

[0127] The variables chromaUpsamplingFlag, resolutionResamplingFlag, pictureRateUpsamplingFlag, bitDepthUpsamplingFlag, and colorizationFlag, which specify whether nnpfc_purpose indicates the purpose of the NNPF, including chroma upsampling, resolution resampling, pictureRateUpsamplingFlag, bitDepthUpsamplingFlag, and colorizationFlag, respectively, can be derived as shown in Table 4 below.

[0128] [Table 4] If the reserved values ​​of nnpfc_purpose are used in the future, the syntax of the SEI message may be extended to a syntax element whose presence or absence is determined by the nnpfc_purpose that matches the corresponding value.

[0129] If ChromaFormatIdc is 3, then chromaUpsamplingFlag must be equal to 0.

[0130] If ChromaFormatIdc or chromaUpsamplingFlag is not 0, then colorizationFlag must be equal to 0.

[0131] If pictureRateUpsamplingFlag is 1 and an input picture with index 0 is associated with a frame packing arrangement SEI message with fp_arrangement_type equal to 5, then all input pictures may be associated with frame packing arrangement SEI messages with fp_arrangement_type equal to 5 and the same value of fp_current_frame_is_frame0_flag.

[0132] nnpfc_id may contain an identification number that can be used to identify a post-processing filter. nnpfc_id values ​​MUST be in the range 0 to 232-2. nnpfc_id values ​​in the ranges 256 to 511 and 231 to 232-2 may be reserved for future use. Decoders MUST ignore NNPFC SEI messages with nnpfc_id in the ranges 256 to 511 or 231 to 232-2.

[0133] If the NNPFC SEI message is the first NNPFC SEI message in decoding order having a particular nnpfc_id value in the current Coded Layer Video Sequence (CLVS), the following may apply.

[0134] The SEI message may indicate a base post-processing filter (NNPF).

[0135] The SEI message may relate to the currently decoded picture and all subsequent decoded pictures of the current layer, in output order, until the current CLVS is finished.

[0136] A value of 1 for nnpfc_base_flag can indicate that the SEI message specifies a base NNPF. A value of 0 for nnpfc_base_flag can indicate that the SEI message specifies an update related to the base NNPF.

[0137] The following constraints may apply to the nnpfc_base_flag value:

[0138] If the NNPFC SEI message is the first NNPFC SEI message in decoding order with a particular nnpfc_id value in the current CLVS, the nnpfc_base_flag value must be equal to 1.

[0139] If NNPFC SEI message nnpfcB is not the first NNPFC SEI message in decoding order with a particular nnpfc_id value in the current CLVS and the nnpfc_base_flag value is equal to 1, then the NNPFC SEI message must be a repeat of the first NNPFC SEI message nnpfcA with the same nnpfc_id value in decoding order, i.e., the payload content of nnpfcB must be identical to the payload content of nnpfcA.

[0140] If nnpfc_base_flag is 0, the following may apply:

[0141] The SEI message may define updates relative to the preceding base NNPF in decoding order having the same nnpfc_id value. Updates are not cumulative; rather, each update may be applied to the base NNPF currently defined by the NNPF SEI message with a particular nnpfc_id value, which is the first NNPF in decoding order. The NNPF defined by the SEI message may be obtained by applying the updates defined by the SEI message to the base NNPF with the same nnpfc_id value.

[0142] The SEI message relates to the currently decoded picture and all subsequent decoded pictures of the current layer in output order until the current CLVS ends or until a decoded picture that comes after the currently decoded picture in output order within the current CLVS is removed, and may relate to a subsequent NNPFC SEI message in decoding order whose nnpfc_base_flag is 0 and has an earlier specific nnpfc_id value within the current CLVS.

[0143] A value of 0 for nnpfc_mode_idc may indicate that the SEI message specifies a base NNPF (if nnpfc_base_flag is 1) or contains a bitstream compliant with ISO / IEC 15938-17 that is an update relative to a base NNPF with the same nnpfc_id value (if nnpfc_base_flag is 0).

[0144] When nnpfc_mode_idc is 1, the value 1 of nnpfc_mode_idc may indicate that the basic NNPF associated with the nnpfc_id value is a neural network, and the neural network may be a neural network identified by a URI indicated in nnpfc_uri using the format identified in the tag URI nnpfc_tag_uri.

[0145] If nnpfc_mode_idc is 0, a value of 1 in nnpfc_mode_idc can indicate that updates to a base NNPF with the same nnpfc_id value are defined at the URI indicated by nnpfc_uri using the format identified by the tag URI nnpfc_tag_uri.

[0146] Values ​​of nnpfc_mode_idc MUST be present in the bitstream in the range 0 to 1. Values ​​in the range 2 to 255 for nnpfc_mode_idc MAY be reserved for future use and MAY not be present in the bitstream. Decoders MUST ignore NNPFC SEI messages with nnpfc_mode_idc in the range 2 to 255. Values ​​of nnpfc_mode_idc greater than 255 MAY not be present in the bitstream and MAY not be reserved for future use.

[0147] nnpfc_reserved_zero_bit_a MUST be equal to 0 in the bitstream. Decoders MUST ignore NNPFC SEI messages with nnpfc_reserved_zero_bit_a not equal to 0.

[0148] The nnpfc_tag_uri may contain a tag URI having syntax and semantics specified in IETF RFC 4151 that identifies the format and associated information for an update relative to the neural network being used as the base NNPF or the base NNPF having the same nnpfc_id value identified by the nnpfc_uri.

[0149] The nnpfc_tag_uri can uniquely identify the type of neural network data specified by the nnrpf_uri without a central registry.

[0150] An nnpfc_tag_uri equal to "tag:iso.org,2023:15938-17" can indicate that the neural network data identified by the nnpfc_uri complies with ISO / IEC 15938-17.

[0151] The nnpfc_uri may contain a URI with syntax and semantics specified in IETF Internet Standard 66 that identifies a neural network used as a base NNPF or an update to a base NNPF with the same nnpfc_id value.

[0152] A value of 1 for nnpfc_formatting_and_purpose_flag can indicate the presence of syntax elements related to the filter's purpose, input formatting, output formatting, and complexity. A value of 0 for nnpfc_formatting_and_purpose_flag can indicate the absence of syntax elements related to the filter's purpose, input formatting, output formatting, and complexity.

[0153] If nnpfc_base_flag is 1, then nnpfc_property_present_flag must be equal to 1.

[0154] If nnpfc_property_present_flag is 0, the values ​​of all syntax elements that can only be present when nnpfc_property_present_flag is 1 can be inferred to be identical to their respective syntax elements in the NNPFC SEI message containing the basic NNPF to which the SEI message provides updates.

[0155] If the NNPFC SEI message nnpfcCurr is not the first NNPFC SEI message in decoding order currently having a particular nnpfc_id value in the CLVS, is not a repeat of the first NNPFC SEI message having the particular nnpfc_id value (i.e., the nnpfc_base_flag value is equal to 0), and the value of nnpfc_property_present_flag is equal to 1, the following constraint may apply.

[0156] The nnpfc_purpose value of the NNPFC SEI message must be the same as the nnpfc_purpose value of the first NNPFC SEI message in decoding order that has a specific nnpfc_id value in the current CLVS.

[0157] In the NNPFC SEI message, the values ​​of the syntax elements that come before nnpfc_complexity_info_present_flag and after nnpfc_property_present_flag in decoding order must be the same as the values ​​of the corresponding syntax elements of the first NNPFC SEI message in decoding order that currently has a specific nnpfc_id value in the CLVS.

[0158] In the first NNPFC SEI message in decoding order currently having a particular nnpfc_id value in CLVS, nnpfc_complexity_info_present_flag (denoted by nnpfcBase below) must be equal to 0 or all nnpfc_complexity_info_present_flag must be equal to 1, and all of the following may apply:

[0159] The nnpfc_parameter_type_idc of nnpfcCurr must be the same as the nnpfc_parameter_type_idc of nnpfcBase.

[0160] The nnpfc_log2_parameter_bit_length_minus3 of nnpfcCurr, if present, must be less than or equal to the nnpfc_log2_parameter_bit_length_minus3 of nnpfcBase.

[0161] If nnpfc_num_parameters_idc of nnpfcBase is 0, then nnpfc_num_parameters_idc of nnpfcCurr must be equal to 0.

[0162] Otherwise (nnpfc_num_parameters_idc in nnpfcBase is greater than 0), nnpfc_num_parameters_idc in nnpfcCurr must be greater than 0 and less than or equal to nnpfc_num_parameters_idc in nnpfcBase.

[0163] If nnpfc_num_kmac_operations_idc of nnpfcBase is 0, nnpfc_num_kmac_operations_idc of nnpfcCurr must be equal to 0.

[0164] Otherwise (nnpfc_num_kmac_operations_idc in nnpfcBase is greater than 0), nnpfc_num_kmac_operations_idc in nnpfcCurr must be greater than 0 and less than or equal to nnpfc_num_kmac_operations_idc in nnpfcBase.

[0165] If nnpfc_total_kilobyte_size of nnpfcBase is 0, nnpfc_total_kilobyte_size of nnpfcCurr must be equal to 0.

[0166] Otherwise (nnpfc_total_kilobyte_size in nnpfcBase is greater than 0), nnpfc_total_kilobyte_size in nnpfcCurr must be greater than 0 and less than or equal to nnpfc_total_kilobyte_size in nnpfcBase.

[0167] nnpfc_num_input_pics_minus1+_1 can indicate the number of pictures used as input for the NNPF. The value of nnpfc_num_input_pics_minus1 must be in the range of 0 to 63. If pictureRateUpsamplingFlag is equal to 1, the value of nnpfc_num_input_pics_minus1 must be greater than 0.

[0168] The variable numInputPics, which indicates the number of pictures used in the input to the NNPF, can be derived as shown in Table 5 below.

[0169] [Table 5] A value of 1 for nnpfc_input_pic_output_flag[i] can indicate that the NNPF generates the corresponding output picture for the i-th input picture. A value of 0 for nnpfc_input_pic_output_flag[i] can indicate that the NNPF does not generate the corresponding output picture for the i-th input picture. If nnpfc_num_input_pics_minus1 is equal to 0, nnpfc_input_pic_output_flag[0] can be inferred to be 1. If pictureRateUpsamplingFlag is equal to 0 and nnpfc_num_input_pics_minus1 is greater than 0, nnpfc_input_pic_output_flag[i] must be equal to 1 for at least one value of i in the range 0 to nnpfc_num_input_pics_minus1.

[0170] A value of 1 for nnpfc_absent_input_pic_zero_flag may indicate that the NNPF expects input pictures that are not present in the bitstream to be represented by a sample array whose sample value is 0. A value of 0 for nnpfc_absent_input_pic_zero_flag may indicate that the NNPF expects input pictures that are not present in the bitstream to be represented by the nearest input picture in output order within the bitstream.

[0171] nnpfc_out_sub_c_flag can indicate the values ​​of the variables outSubWidthC and outSubHeightC when chromaUpsamplingFlag is 1. A value of 1 for nnpfc_out_sub_c_flag can indicate that the value of outSubWidthC is 1 and the value of outSubHeightC is 1. A value of 0 for nnpfc_out_sub_c_flag can indicate that the value of outSubWidthC is 2 and the value of outSubHeightC is 1. If the value of ChromaFormatIdc is 2 and nnpfc_out_sub_c_flag is present, the value of nnpfc_out_sub_c_flag must be equal to 1.

[0172] nnpfc_out_colour_format_idc can indicate the hue format of the NNPF and consequently the values ​​of the variables outSubWidthC and outSubHeightC when colourizationFlag is 1. A value of 1 for nnpfc_out_colour_format_idc can indicate that the NNPF output hue format is 4:2:0, and that outSubWidthC and outSubHeightC are both 2. A value of 2 for nnpfc_out_colour_format_idc can indicate that the NNPF output hue format is 4:2:2, and that outSubWidthC is 2 and outSubHeightC is 1. A value of 3 for nnpfc_out_colour_format_idc can indicate that the NNPF output hue format is 4:4:4, and that outSubWidthC and outSubHeightC are both 1. The value of nnpfc_out_colour_format_idc must not be 0.

[0173] If chromaUpsamplingFlag and colorizationFlag are both 0, then outSubWidthC and outSubHeightC can be inferred to be identical to SubWidthC and SubHeightC, respectively.

[0174] nnpfc_pic_width_num_minus1+1 and nnpfc_pic_width_denom_minus1+1 may indicate the numerator and denominator, respectively, for the resampling ratio of the NNPF output picture width with respect to CroppedWidth. The value of (nnpfc_pic_width_num_minus1+1)÷(nnpfc_pic_width_denom_minus1+1) must lie in the range 1÷16 to 16. If nnpfc_pic_width_num_minus1 and nnpfc_pic_width_denom_minus1 are not present, the values ​​of nnpfc_pic_width_num_minus1 and nnpfc_pic_width_denom_minus1 can be inferred to be both equal to 0.

[0175] The variable nnpfcOutputPicWidth, which indicates the width of the luma sample array of the picture(s) resulting from applying the NNPF identified by nnpfc_id to the input picture(s), can be derived as shown in Table 6 below.

[0176] [Table 6] It is a bitstream conformance requirement that the value of nnpfcOutputPicWidth%outSubWidthC must be equal to 0.

[0177] nnpfc_pic_height_num_minus1+1 and nnpfc_pic_height_denom_minus1+1 may indicate the numerator and denominator, respectively, for the resampling ratio of the NNPF output picture height with respect to CroppedHeight. The value of (nnpfc_pic_height_num_minus1+1)÷(nnpfc_pic_height_denom_minus1+1) must lie in the range 1÷16 to 16. If nnpfc_pic_height_num_minus1 and nnpfc_pic_height_denom_minus1 are not present, the values ​​of nnpfc_pic_height_num_minus1 and nnpfc_pic_height_denom_minus1 can both be inferred to be equal to 0.

[0178] The variable nnpfcOutputPicHeight, which indicates the height of the luma sample array of the picture(s) resulting from applying the NNPF identified by nnpfc_id to the input picture(s), can be derived as shown in Table 7 below.

[0179] [Table 7] It is a bitstream conformance requirement that the value of nnpfcOutputPicHeight%outSubHeightC must be equal to 0.

[0180] If nnpfc_pic_width_num_minus1, nnpfc_pic_width_denom_minus1, nnpfc_pic_height_num_minus1, and nnpfc_pic_height_denom_minus1 exist, then at least one of the following must be true:

[0181] The value of nnpfcOutputPicWidth is not equal to CroppedWidth.

[0182] The value of nnpfcOutputPicHeight is not equal to CroppedHeight.

[0183] nnpfc_interpolated_pics[i] can indicate the number of interpolated pictures generated by the NNPF between the ith picture and the (i+1)th picture used as input to the NNPF. The value of nnpfc_interpolated_pics[i] must be in the range of 0 to 63. The value of nnpfc_interpolated_pics[i] must be in the range of 0 to nnpfc_num_input_pics_minus1-1 and greater than 0 for at least one value of i.

[0184] The variable NumInpPicsInOutputTensor indicating the number of pictures present in the output tensor of the NNPF with the corresponding input picture, InpIdx[idx] indicating the input picture index of the idxth picture present in the output tensor of the NNPF with the corresponding input picture, and numOutputPics indicating the total number of pictures present in the output tensor of the NNPF can be derived as shown in Table 8 below.

[0185] [Table 8] A value of 1 for nnpfc_component_last_flag can indicate that the last dimension of the input tensor inputTensor for the NNPF and the output tensor outputTensor that is the result of the NNPF are currently used for the channel. A value of 0 for nnpfc_component_last_flag can indicate that the third dimension of the input tensor inputTensor for the NNPF and the output tensor outputTensor that is the result of the NNPF are currently used for the channel.

[0186] The first dimension of the input tensor and output tensor can be used as the batch index used in some neural network frameworks. The formula in the semantics of this SEI message uses the batch size corresponding to the batch index equal to 0, but the size of the batch used as input for neural network inference can be determined by the implementation of post-processing.

[0187] For example, when the value of nnpfc_inp_order_idc is equal to 3 and the value of nnpfc_auxiliary_inp_idc is equal to 1, the input tensor can have seven channels including four luma matrices, two chroma matrices, and one auxiliary input matrix. In this case, the DeriveInputTensors() process can derive each of the seven channels of the input tensor one by one, and when a specific channel among these channels is processed, the corresponding channel can be referred to as the current channel of the process.

[0188] nnpfc_inp_format_idc can indicate how to convert the sample values ​​of the input picture into the input values ​​of the NNPF. If nnpfc_inp_format_idc is 0, the input values ​​for the NNPF are real numbers and the functions InpY() and InpC() can be specified as shown in Table 9 below.

[0189] [Table 9] If the value of nnpfc_inp_format_idc is 1, the input values ​​of the NNPF are unsigned integer numbers, and the functions InpY() and InpC() can be derived as shown in Tables 10 and 11.

[0190] [Table 10]

[0191] [Table 11] The variable inpTensorBitDepthy may be derived from the syntax element nnpfc_inp_tensor_bitlength_minus8 described below. inpTensorBitDepthC may be derived from the syntax element nnpfc_inp_tensor_chroma_bitdepth_minus8 described below.

[0192] Values ​​of nnpfc_inp_format_idc greater than 1 may be reserved for future use and may not be present in the bitstream. Decoders MUST ignore NNPFC SEI messages that contain reserved values ​​of nnpfc_inp_format_idc.

[0193] An nnpfc_auxiliary_inp_idc greater than 0 may indicate that auxiliary input data is present in the input tensor of the NNPF. A value of 0 for nnpfc_auxiliary_inp_idc may indicate that auxiliary input data is not present in the input tensor. A value of 1 for nnpfc_auxiliary_inp_idc may indicate that auxiliary input data is induced as described in Equation 5 below.

[0194] The value of nnpfc_auxiliary_inp_idc must be in the range 0 to 1 in the bitstream.

[0195] Values ​​2 to 255 for nnpfc_auxiliary_inp_idc may be reserved for future use and may not be present in the bitstream. Decoders MUST ignore NNPFC SEI messages containing nnpfc_auxiliary_inp_idc in the range 2 to 255. Values ​​of nnpfc_auxiliary_inp_idc greater than 255 will not be present in the bitstream and are not reserved for future use.

[0196] nnpfc_inp_order_idc can indicate how to order the sample array of the input picture to form the input tensor for the NNPF.

[0197] Values ​​of nnpfc_inp_order_idc MUST be in the range 0 to 3 in the bitstream. Values ​​4 to 255 for nnpfc_inp_order_idc MAY be reserved for future use and will not be present in the bitstream. Decoders MUST ignore NNPFC SEI messages with nnpfc_inp_order_idc in the range 4 to 255. Values ​​of nnpfc_inp_order_idc greater than 255 will not be present in the bitstream and are not reserved for future use.

[0198] If the value of ChromaFormatIdc is not 1, the value of nnpfc_inp_order_idc must not be 3.

[0199] If ChromaFormatIdc is 0, nnpfc_inp_order_idc must be equal to 0.

[0200] If chromaUpsamplingFlag is 1, nnpfc_inp_order_idc must not be 0.

[0201] Table 12 contains descriptions for the nnpfc_inp_order_idc values.

[0202] [Table 12] FIG. 5 referred to in Table 12 is a diagram for explaining an interleaving scheme for deriving the luma channel.

[0203] nnpfc_inp_tensor_bitlength_minus8+8 can indicate the bit depth of the luma sample values ​​in the input constant tensor. The value of inpTensorBitDepthY can be derived as shown in Table 13.

[0204] [Table 13] It is a bitstream conformance requirement that the value of nnpfc_inp_tensor_luma_bitdepth_minus8 must be in the range 0 to 24.

[0205] nnpfc_inp_tensor_chroma_bitdepth_minus8+8 can indicate the bit depth of the chroma sample values ​​in the input constant tensor. The value of inpTensorBitDepthC can be derived as shown in Table 14.

[0206] [Table 14] It is a bitstream conformance requirement that the value of nnpfc_inp_tensor_chroma_bitdepth_minus8 must be in the range 0 to 24.

[0207] If nnpfc_auxiliary_inp_idc is 1, the variable strengthControlScaledVal can be derived as shown in Table 15 below.

[0208] [Table 15] A patch may be a rectangular array of samples from a component of a picture (eg, luma or chroma component).

[0209] The process DeriveInputTensors() for deriving the input tensor inputTensor with respect to the horizontal sample coordinate cLeft that specifies the top-left sample position for the given vertical sample coordinate cTop and the patch of samples included in the input tensor can be shown as a combination in Table 16.

[0210] [Table 16] For the value 0 of nnpfc_out_format_id, it can be shown that the sample values output to the NNPF are real numbers linearly mapped to the unsigned integer value range of 0 to (1<<bitDepth)-1 for the desired bit depth bitDepth for subsequent post-processing or display. Here, the real number can be in the value range of 0 to 1.

[0211] The value 1 of nnpfc_out_format_flag indicates that the luma sample values output by the NNPF are unsigned integers in the range of 0 to (1<<outTensorBitDepthY)-1, and the chroma sample values output by the NNPF are unsigned integers in the range of (1<<outTensorBitDepthC)-1.

[0212] Values of nnpfc_out_format_idc greater than 1 may be reserved for future specifications and do not exist in the bitstream. The decoder must ignore NNPFC SEI messages containing reserved values of nnpfc_out_format_idc.

[0213] nnpfc_out_order_idc can indicate the output order of samples by the NNPF.

[0214] Values ​​of nnpfc_out_order_idc MUST be in the range 0 to 3 in the bitstream. Values ​​4 to 255 for nnpfc_out_order_idc MAY be reserved for future use and will not be present in the bitstream. Decoders MUST ignore NNPFC SEI messages containing nnpfc_out_order_idc in the range 4 to 255. Values ​​of nnpfc_out_order_idc greater than 255 will not be present in the bitstream and are not reserved for future use.

[0215] If chromaUpsamplingFlag is 1, nnpfc_out_order_idc must not be 0 or 3.

[0216] If colorizationFlag is 1, nnpfc_out_order_idc must not be 0.

[0217] Table 17 contains descriptions for the nnpfc_out_order_idc values.

[0218] [Table 17] nnpfc_out_tensor_luma_bitdepth_minus8+8 can indicate the bit depth of the luma sample values ​​of the output constant tensor. The value of nnpfc_out_tensor_luma_bitdepth_minus8 must be in the range of 0 to 24. The value of outTensorBitDepthY can be derived as shown in Table 18.

[0219] [Table 18] nnpfc_out_tensor_chroma_bitdepth_minus8+8 can indicate the bit depth of the chroma sample values ​​of the output constant tensor. The value of nnpfc_out_tensor_chroma_bitdepth_minus8 must be in the range of 0 to 24. The value of outTensorBitDepthC can be derived as shown in Table 19.

[0220] [Table 19] If bitDepthUpsamplingFlag is 1, the value of nnpfc_out_format_idc must be equal to 1, and at least one of the following conditions must be met:

[0221] nnpfc_out_tensor_luma_bitdepth_minus8 exists and outTensorBitDepthY is greater than BitDepthY.

[0222] nnpfc_out_tensor_chroma_bitdepth_minus8 exists and outTensorBitDepthC is greater than BitDepthC.

[0223] If nnpfc_inp_tensor_luma_bitdepth_minus8, nnpfc_inp_tensor_chroma_bitdepth_minus8, nnpfc_out_tensor_luma_bitdepth_minus8, and nnpfc_out_tensor_chroma_bitdepth_minus8 are present and outTensorBitDepthY is greater than inpTensorBitDepthY, then outTensorBitDepthC must be less than inpTensorBitDepthC.

[0224] If nnpfc_inp_tensor_luma_bitdepth_minus8, nnpfc_inp_tensor_chroma_bitdepth_minus8, nnpfc_out_tensor_luma_bitdepth_minus8, and nnpfc_out_tensor_chroma_bitdepth_minus8 are present and outTensorBitDepthC is greater than inpTensorBitDepthC, then outTensorBitDepthY must be less than inpTensorBitDepthY.

[0225] The process StoreOutputTensors() for deriving sample values ​​in filtered output sample arrays FilteredYPic, FilteredCbPic, and FilteredCrPic from the output tensor outputTensor for a given vertical sample coordinate cTop and horizontal sample coordinate cLeft indicating the top left sample position for the patch of samples contained in the input tensor can be expressed as the combination of Table 20.

[0226] [Table 20] JPEG2026505576000027.jpg114129JPEG2026505576000028.jpg207133A value of 1 for nnpfc_separate_colour_description_present_flag can indicate that the unique combination of color primaries, transformation characteristics, matrix coefficients, and scaling and offset values ​​applied in conjunction with the matrix coefficients for the picture by the NNPF is specified in the SEI message syntax structure.A value of 0 for nnpfc_separate_colour_description_present_flag can indicate that the combination of color primaries, transformation characteristics, matrix coefficients, and scaling and offset values ​​applied in conjunction with the matrix coefficients for the picture by the post-processing filter is the same as that displayed in the VUI parameters of the CLVS.

[0227] nnpfc_colour_primaries may have the same semantics as defined for the vui_colour_primaries syntax element, except for the following:

[0228] nnpfc_colour_primaries can indicate the primary colours of the picture that are displayed as a result of applying the NNPF specified in the SEI message, which are not the primary colours used in CLVS.

[0229] If nnpfc_colour_primaries is not present in the NNPFC SEI message, the value of nnpfc_colour_primaries can be inferred to be the same as the value of vui_colour_primaries.

[0230] nnpfc_transfer_characteristics may have the same semantics as defined for the vui_transfer_characteristics syntax element, except for the following:

[0231] nnpfc_transfer_characteristics can indicate the transfer characteristics of the picture that are not the transfer characteristics used in CLVS, but are the result of applying the NNPF specified in the SEI message.

[0232] If nnpfc_transfer_characteristics is not present in the NNPFC SEI message, the value of nnpfc_transfer_characteristics can be inferred to be the same as the value of vui_transfer_characteristics.

[0233] nnpfc_matrix_coeffs may describe the formulas used to derive luma and chroma signals for green, blue, red or Y, Z, X primaries. Its semantics are applied to the picture shown as a result of applying the NNPF specified in the SEI message, and may be the same as those specified for MatrixCoefficients including outTensorBitDepthC and BitDepthC, which are the same as outTensorBitDepthY and outTensorBitDepthC, respectively.

[0234] If nnpfc_matrix_coeffs is not present in the NNPFC SEI message, the value of nnpfc_matrix_coeffs can be inferred to be the same as the value of vui_matrix_coeffs.

[0235] nnpfc_matrix_coeffs cannot be equal to 0 unless all of the following conditions are true:

[0236] nnpfc_out_tensor_chroma_bitdepth_minus8 is the same as nnpfc_out_tensor_luma_bitdepth_minus8.

[0237] nnpfc_out_order_idc is equal to 2, outSubHeightC is equal to 1, and outSubWidthC is equal to 1.

[0238] nnpfc_matrix_coeffs cannot be equal to 8 unless one of the following conditions is true:

[0239] nnpfc_out_tensor_chroma_bitdepth_minus8 is the same as nnpfc_out_tensor_luma_bitdepth_minus8.

[0240] nnpfc_out_tensor_chroma_bitdepth_minus8 is the same as nnpfc_out_tensor_luma_bitdepth_minus8+1, nnpfc_out_order_idc is the same as 2, outSubHeightC is the same as 1, and outSubWidthC is the same as 1.

[0241] nnpfc_full_range_flag can indicate the applied scaling and offset values ​​related to the matrix coefficients, as specified by nnpfc_matrix_coeffs. Its semantics can be identical to that specified for the VideoFullRangeFlag parameter. If it is not present, the value of nnpfc_full_range_flag can be inferred to be identical to 0.

[0242] A value of 1 for nnpfc_chroma_loc_info_present_flag can indicate the presence of the nnpfc_chroma_sample_loc_type_frame syntax element in the NNPFC SEI message. A value of 0 for nnpfc_chroma_loc_info_present_flag can indicate the absence of the nnpfc_chroma_sample_loc_type_frame syntax element in the NNPFC SEI message. If colourizationFlag is 0 or nnpfc_out_colour_format_idc is not 1, the value of nnpfc_chroma_loc_info_present_flag must be equal to 0.

[0243] nnpfc_chroma_sample_loc_type_frame can indicate the location of the chroma samples in the output picture if nnpfc_chroma_sample_loc_type_frame is not 6 and nnpfc_out_colour_format_idc is equal to 1. If nnpfc_chroma_sample_loc_type_frame is 6 and nnpfc_out_colour_format_idc is equal to 1, it can indicate that the chroma sample locations are not known, are not specified, or are specified by other means. The value of nnpfc_chroma_sample_loc_type_frame must be in the range 0 to 6.

[0244] nnpfc_overlap can indicate the number of overlapping horizontal and vertical samples of adjacent input tensors of NNPF. The value of nnpfc_overlap must be in the range of 0 to 16383.

[0245] A value of 1 for nnpfc_constant_patch_size_flag can indicate that the NNPF accepts as input exactly the patch size indicated by nnpfc_patch_width_minus1 and nnpfc_patch_height_minus1. A value of 0 for nnpfc_constant_patch_size_flag can indicate that the NNPF accepts as input all patch sizes whose width is inpPatchWidth and whose height is inpPatchHeight. This allows the width of the extended patch (i.e., patch + overlapping area) equal to inpPatchWidth+2*nnpfc_overlap to be a positive integer multiple of nnpfc_extended_patch_width_cd_delta_minus1+1+2*nnpfc_overlap, and the height of the extended patch equal to inpPatchHeight+2*nnpfc_overlap to be a positive integer multiple of nnpfc_extended_patch_height_cd_delta_minus1+1+2*nnpfc_overlap.

[0246] npfc_patch_width_minus1+1 can indicate the number of horizontal samples of the patch size required for the NNPF input when the value of nnpfc_constant_patch_size_flag is 1. The value of nnpfc_patch_width_minus1 must be in the range of 0 to Min(32766, CroppedWidth-1).

[0247] npfc_patch_height_minus1+1 can indicate the number of vertical samples of the patch size required for the NNPF input when the value of nnpfc_constant_patch_size_flag is 1. The value of nnpfc_patch_height_minus1 must be in the range of 0 to Min(32766, CroppedHeight-1).

[0248] nnpfc_extended_patch_width_cd_delta_minus1+1+2*nnpfc_overlap can indicate the common divisor of all allowed values ​​of the extended patch width required as input to the NNPF when nnpfc_constant_patch_size_flag is 0. The value of nnpfc_extended_patch_width_cd_delta_minus1 must be in the range 0 to Min(32766, CroppedWidth-1).

[0249] nnpfc_extended_patch_height_cd_delta_minus1+1+2*nnpfc_overlap can indicate the common divisor of all allowed values ​​of the extended patch height required as input to the NNPF when nnpfc_constant_patch_size_flag is 0. The value of nnpfc_extended_patch_height_cd_delta_minus1 must be in the range 0 to Min(32766, CroppedHeight-1).

[0250] The variables inpPatchWidth and inpPatchHeight can be set to the patch size width and patch size height, respectively.

[0251] If the value of nnpfc_constant_patch_size_flag is 0, the following may apply:

[0252] The values ​​of inpPatchWidth and inpPatchHeight can be provided by external means or can be set by the post-processor itself.

[0253] The value of inpPatchWidth+2*nnpfc_overlap must be a positive integer multiple of ofnnpfc_extended_patch_width_cd_delta_minus1+1+2*nnpfc_overlap, and inpPatchWidth must be less than or equal to CroppedWidth. The value of inpPatchHeight+2*nnpfc_overlap must be a positive integer multiple of ofnnpfc_extended_patch_height_cd_delta_minus1+1+2*nnpfc_overlap, and inpPatchHeight must be less than or equal to CroppedHeight.

[0254] Otherwise (the value of nnpfc_constant_patch_size_flag is equal to 1), the value of inpPatchWidth may be set equal to nnpfc_patch_width_minus1+1, and the value of inpPatchHeight may be set equal to nnpfc_patch_height_minus1+1.

[0255] The variables outPatchWidth, outPatchHeight, horCScaling, verCScaling, outPatchCWidth, outPatchCHeight, and overlapSize may be derived as in Table 21.

[0256] [Table 21] It is a bitstream conformance requirement that outPatchWidth*CroppedWidth must be equal to nnpfc_pic_width_in_luma_samples*inpPatchWidth and outPatchHeight*CroppedHeight must be equal to nnpfc_pic_height_in_luma_samples*inpPatchHeight.

[0257] As described in Table 22, nnpfc_padding_type can indicate the process of padding when referring to sample positions outside the boundaries of the input picture.

[0258]

Table 22

[0259] When the value of nnpfc_padding_type is 4, nnpfc_luma_padding_val can indicate the luma value used for padding. The value of nnpfc_luma_padding_val must exist in the range of 0 to (1<<BitDepthY)-1.

[0260] When the value of nnpfc_padding_type is 4, nnpfc_cb_padding_val can indicate the Cb value used for padding. The value of nnpfc_cb_padding_val must exist in the range of 0 to (1<<BitDepthC)-1.

[0261] When the value of nnpfc_padding_type is 4, nnpfc_cr_padding_val can indicate the Cr value used for padding. The value of nnpfc_cr_padding_val must exist in the range of 0 to (1<<BitDepthC)-1.

[0262] The function InpSampleVal(y, x, picHeight, picWidth, CroppedPic) with inputs of vertical sample position y, horizontal sample position x, picture height picHeight, picture width picWidth, sample array CroppedPic, and component index cIdx (equal to 0 for luma, equal to 1 for Cb, and equal to 2 for Cr) can return the value of SampleVal derived as shown in Table 23.

[0263] [Table 23] For input to the function InpSampleVal(), the vertical positions may be listed before the horizontal positions for compatibility with the input tensor rules of some inference engines.

[0264] The NNPF PostProcessingFilter() may be a target NNPF guided by the semantics of the NNPFA SEI message. The following example process may be used to generate filtered and / or interpolated picture(s) in a patch-wise manner. The filtered and / or interpolated picture(s) may include a Y sample array, FilteredYPic, a Cb sample array, FilteredCbPic, and a Cr sample array, FilteredCrPic, as specified by nnpfc_out_order_idc.

[0265] [Table 24] The NNPF-generated picture containing index i may contain sample arrays FilteredYPic[i], FilteredCbPic[i], and FilteredCrPic[i], if present, guided by Table 19. The NNPF-generated picture may not contain overlap regions.

[0266] The NNPF process may output NNPF-generated pictures in their increasing index order to form the process defined by Table 19, where all NNPF-generated pictures interpolated by the NNPF are output, and the NNPF-generated pictures corresponding to all input pictures to the NNPF may be output as specified in the semantics of the NNPFA SEI message.

[0267] A value of 1 for nnpfc_complexity_info_present_flag can indicate the presence of one or more syntax elements that indicate the complexity of the NNPF associated with nnpfc_id. A value of 0 for nnpfc_complexity_info_present_flag can indicate the absence of syntax elements that indicate the complexity of the NNPF associated with nnpfc_id.

[0268] A value of 0 for nnpfc_parameter_type_idc can indicate that the neural network uses integer parameters only. A value of 1 for nnpfc_parameter_type_flag can indicate that the neural network can use floating-point or integer parameters. A value of 2 for nnpfc_parameter_type_idc can indicate that the neural network uses binary parameters only. A value of 3 for nnpfc_parameter_type_idc may be reserved for future use and will not be present in the bitstream. Decoders must ignore NNPFC SEI messages with a value of 3 for nnpfc_parameter_type_idc.

[0269] nnpfc_log2_parameter_bit_length_minus3 values ​​0, 1, 2, and 3 can indicate that the neural network does not use parameters with bit lengths greater than 8, 16, 32, and 64, respectively. If nnpfc_parameter_type_idc is present and nnpfc_log2_parameter_bit_length_minus3 is not present, the neural network does not use parameters with bit lengths greater than 1.

[0270] nnpfc_num_parameters_idc can indicate the maximum number of neural network parameters for the NNPF in powers of 2048. A value of 0 for nnpfc_num_parameters_idc can indicate that the maximum number of neural network parameters is unknown. Values ​​of nnpfc_num_parameters_idc MUST be in the range 0 to 52. Values ​​of nnpfc_num_parameters_idc greater than 52 MAY be reserved for future use and will not be present in the bitstream. Decoders MUST ignore NNPFC SEI messages with nnpfc_num_parameters_idc greater than 52.

[0271] If the value of nnpfc_num_parameters_idc is greater than 0, the variable maxNumParameters may be derived as shown in Table 25.

[0272] [Table 25] It is a bitstream conformance requirement that the number of neural network parameters in an NNPF must be less than or equal to maxNumParameters.

[0273] An nnpfc_num_kmac_operations_idc greater than 0 can indicate that the maximum number of multiply-accumulate operations per sample of the NNPF is less than or equal to nnpfc_num_kmac_operations_idc * 1000. A value of 0 for nnpfc_num_kmac_operations_idc can indicate that the maximum number of multiply-accumulate operations of the network is unknown. The value of nnpfc_num_kmac_operations_idc must lie in the range of 0 to 2-2.

[0274] A value of nnpfc_total_kilobyte_size greater than 0 can indicate the total size (in kilobytes) required to store the uncompressed parameters of the neural network. The total size in bits can be a number greater than or equal to the sum of the bits used to store each parameter. nnpfc_total_kilobyte_size can be the total size (in bits) divided by 8000 and rounded up or down. A value of 0 for nnpfc_total_kilobyte_size can indicate that the total size required to store the parameters for the neural network is unknown. The value of nnpfc_total_kilobyte_size must be in the range of 0 to 2-2.

[0275] A value of 0 for nnpfc_metadata_extension_num_bits can indicate that no nnpfc_reserved_metadata_extension is present. A value of nnpfc_metadata_extension_num_bits greater than 0 can indicate the length of the nnpfc_reserved_metadata_extension in bits. nnpfc_metadata_extension_num_bits must be equal to 0. Values ​​in the range 1 to 2048 for nnpfc_metadata_extension_num_bits may be reserved for future use and will not be present in the bitstream. Decoders must accept all values ​​of nnpfc_metadata_extension_num_bits in the range 0 to 2048. Values ​​of nnpfc_metadata_extension_num_bits greater than 2048 will not be present in the bitstream and will not be reserved for future use.

[0276] nnpfc_reserved_metadata_extension shall not be present in the bitstream. However, decoders shall ignore the presence and value of nnpfc_reserved_metadata_extension. If it is present, the length in bits of nnpfc_reserved_metadata_extension may be identical to nnpfc_metadata_extension_num_bits.

[0277] nnpfc_reserved_zero_bit_b MUST be equal to 0 in the bitstream. Decoders MUST ignore NNPFC SEI messages where nnpfc_reserved_zero_bit_b is not equal to 0.

[0278] nnpfc_payload_byte[i] can contain the ith byte of the bitstream. The byte sequence nnpfc_payload_byte[i] for all present values ​​of i must be a complete bitstream conforming to ISO / IEC 15938-17.

[0279] Neural-network post-filter activation (NNPFA) The syntax structure for NNPFA is shown in Table 26.

[0280] [Table 26] The NNPFA SEI message can activate or deactivate the possible use of a target neural network post-processing filter identified by nnpfa_target_id and nnpfc_base_flag for post-processing filtering of a picture set. For a particular picture for which an NNPF is activated, the target NNPF can be derived as follows:

[0281] If nnpfa_target_base_flag is 1, the target NNPF is a base NNPF having the same nnpfc_id as nnpfa_target_id.

[0282] Otherwise (if nnpfa_target_base_flag is 0), the target NNPF is the NNPF identified by the last NNPFC SEI message that precedes the first VCL NAL unit of the current picture in decoding order, is not a repetition of an NNPFC SEI message containing a base NNPF, and has an nnpfc_id that is identical to nnpfa_target_id.

[0283] There can be multiple NNPFA SEI messages for the same picture if the post-processing filter is used for other purposes or filters other hue components.

[0284] nnpfa_target_id can indicate the target NNPF associated with the current picture and specified by one or more NNPFC SEI messages with nnpfc_id equal to nnpfa_target_id. The value of nnpfa_target_id must be in the range of 0 to 2-2.

[0285] An NNPFA SEI message with a specific value of nnpfa_target_id must not currently exist in the Picture Unit (PU) unless one or two of the following conditions are all true:

[0286] Currently in the CLVS there exists an NNPFC SEI message with the same nnpfc_id as the specific value of nnpfa_target_id present in the PU preceding the current PU in decoding order. There is currently an NNPFC SEI message in the PU with an nnpfc_id that is identical to the specified value of nnpfa_target_id. If a PU includes both an NNPFC SEI message with a specific value of nnpfc_id and an NNPFA SEI message with an nnpfa_target_id that is the same as the specific value of nnpfc_id, the NNPFC SEI message must precede the NNPFA SEI message in decoding order.

[0287] A value of 1 for nnpfa_cancel_flag can indicate that the persistence of the target neural network post-processing filter set by any previous NNPFA SEI message with the same nnpfa_target_id as the current SEI message is canceled. That is, the target neural network post-processing filter will no longer be used unless activated by another NNPFA SEI message with the same nnpfa_target_id as the current SEI message and an nnpfa_cancel_flag equal to 0. A value of 0 for nnpfa_cancel_flag can indicate that nnpfa_target_base_flag, nnpfa_persistence_flag, and nnpfa_num_output_entries follow.

[0288] A value of 1 for nnpfa_target_base_flag may indicate that the target NNPF is a base NNPF with the same nnpfc_id as nnpfa_target_id. A value of 0 for nnpfa_target_base_flag may indicate that the target NNPF is the NNPF identified by the last NNPFC SEI message with the same nnpfc_id as nnpfa_target_id that precedes the first VCL NAL unit of the current picture in decoding order.

[0289] nnpfa_persistence_flag can indicate the persistence of the target neural network post-processing filter for the current layer.

[0290] A value of 0 for nnpfa_persistence_flag may indicate that the target neural network post-processing filter can only be used for post-processing filtering on the current picture.

[0291] A value of 1 for nnpfa_persistence_flag may indicate that the target neural network post-processing filter may be used for post-processing filtering on the current picture and all subsequent pictures in the current layer in output order until one or more of the following conditions become true:

[0292] A new CLV for the current layer is started Bitstream ends The picture in the current layer associated with an NNPFA SEI message that has the same nnpfa_target_id as the current SEI message and an nnpfa_cancel_flag equal to 1 is output after the current picture in output order. The target neural network post-processing filter is not applied to subsequent pictures in the current layer associated with an NNPFA SEI message that has the same nnpfa_target_id as the current SEI message and an nnpfa_cancel_flag equal to 1.

[0293] nnpfcTargetPictures shall be the set of pictures associated with the last NNPFC SEI message preceding the current NNPFA SEI message in decoding order and having the same nnpfc_id as nnpfa_target_id. nnpfaTargetPictures shall be the set of pictures for which the target NNPF is activated by the current NNPFA SEI message. It is a bitstream conformance requirement that pictures included in nnpfaTargetPictures must also be included in nnpfcTargetPictures.

[0294] nnpfa_num_output_entries can indicate the number of nnpfa_output_flag[i] syntax elements present in the NNPFA SEI message. The value of nnpfa_num_output_entries is in the range from 0 to NumInpPicsInOutputTensor.

[0295] A value of 1 for nnpfa_output_flag[i] indicates that the NNPF-generated picture corresponding to the input picture with index InpIdx[i] is output by the NNPF process activated by this NNPFA SEI message, where the NNPF process may be specified within the semantics of the NNPFC SEI message. A value of 0 for nnpfa_output_flag[i] may indicate that the NNPF-generated picture corresponding to the input picture with index InpIdx[i] is not output by the NNPF process activated by this NNPFA SEI message. If nnpfa_num_output_entries is less than NumInpPicsInOutputTensor, then nnpfa_output_flag[i] may be inferred to be 1 for each value of i in the range from nnpfa_num_output_entries to NumInpPicsInOutputTensor-1.

[0296] NNPFGC SEI message (Neural-network post-filter group characteristics SEI message) Table 27 shows an example of the NNPFGC SEI message syntax.

[0297] [Table 27] The NNPFGC SEI message specifies an NNPF group. The SEI message indicates whether the NNPF group defines an NNPF cascade, or whether an NNPF or NNPF group in an NNPF cascade is an alternative to another NNPF. The use of an NNPF group in an NNPF cascade for a particular picture is indicated through the NNPFGA SEI message.

[0298] nnpfgc_id contains an identification number that can be used to identify an NNPF group. nnpfgc_id values ​​range from 0 to 2. 32 -2. Must be in the range 256 to 511 and 2 31 From 2 32- nnpfgc_id values ​​up to 2 are reserved for future use by ITU-T | ISO / IEC. 31 From 2 32 Decoders conforming to this document that encounter an NNPFGC SEI message with an nnpfgc_id in the range up to -2 MUST ignore that SEI message. The nnpfgc_id value MUST NOT be the same as any other nnpfgc_id value in any other NNPFGC SEI message present in the same CLVS. If the nnpfgc_id value of an NNPFGC SEI message nnpfgcSeiA is the same as the nnpfgc_id value of another NNPFGC SEI message nnpfgcSeiB present in the same CLVS, then nnpfgcSeiA and nnpfgcSeiB MUST match.

[0299] nnpfgc_grouping_type, if its value is 0, indicates that this SEI message specifies a group of cascaded neural-network post-filters.

[0300] nnpfgc_grouping_type, if its value is 1, indicates that the NNPFs or NNPF groups identified by nnpfgc_member_id[i] are mutually selectable such that the post-processor must select only one of them to apply.

[0301] nnpfgc_grouping_type, if its value is 2, specifies the NNPF group with which this SEI message is intended to be used, and indicates that these NNPFs are alternately activated for at most one or all pictures.

[0302] nnpfgc_grouping_type, if its value is 3, indicates that the NNPF or NNPF group identified by nnpfgc_member_id[i] is intended to be used in parallel.

[0303] nnpfgc_grouping_type, if its value is 4, indicates that the NNPF or NNPF group identified by nnpfgc_member_id[i] is selective, i.e., it may or may not be applied by the post-processor.

[0304] nnpfgc_grouping_type values ​​MUST be in the range 0 to 255. nnpfgc_grouping_type values ​​in the range 5 to 255 are reserved for future clarification by ITU-T | ISO / IEC and MUST NOT be present in bitstreams conforming to this document. Decoders conforming to this document MUST ignore NNPFGC SEI messages with nnpfgc_grouping_type in the range 5 to 255.

[0305] The nnpfgc_purpose has the symmetries of the nnpfgc_purpose, except that the symmetries are specified for the NNPF group defined by this SEI message rather than the NNPF defined by the NNPFC SEI message.

[0306] nnpfgc_num_members_minus2 plus 2 indicates the number of NNPFs or NNPF groups in the NNPF group that this SEI message defines.

[0307] nnpfgc_member_id[i] indicates the i-th member of the NNPF group defined by this SEI message as follows:

[0308] If there is an NNPF having the same nnpfc_id as the nnpfgc_member_id[i] defined in the CLVS, the i-th member of the NNPF group defined by this SEI message is the NNPF having the same nnpfc_id as the nnpfgc_member_id[i].

[0309] Or (if there is no NNPF with the same nnpfc_id as nnpfgc_member_id[i] defined in CLVS), the i-th member of the NNPF group defined by this SEI message is the NNPF group with the same nnpfgc_id as nnpfgc_member_id[i].

[0310] If the nnpfgc_member_id[i] value refers to the nnpfgc_id value of the NNPFGC SEI message nnpfgcSei, it is a bitstream conformance requirement that the NNPFGC SEI message nnpfgcSei must have an nnpfgc_grouping_type whose value is 0. If nnpfgc_grouping_type is 0 or 2, it is a bitstream conformance requirement that there exists an NNPF with an nnpfc_id value identical to nnpfgc_member_id[i] defined in CLVS. If nnpfgc_grouping_type is 1, 3, or 4, it is a bitstream conformance requirement that there exists an NNPF with an nnpfc_id value identical to nnpfgc_member_id[i] or an NNPF group with an nnpfc_id value identical to nnpfgc_member_id[i] defined in CLVS.

[0311] If nnpfgc_grouping_type is 0, NNPFs having the same nnpfc_id as nnpfgc_member_id[i] are cascaded in increasing order of i as activated by NNPFGA SEI messages having the same nnpfga_target_id as nnpfgc_id.

[0312] nnpfgc_complexity_info_present_flag, nnpfgc_parameter_type_idc, nnpfgc_log2_parameter_bit_length_minus3, nnpfgc_num_parameters_idc, nnpfgc_num_kmac_operations_idc, and nnpfgc_total_kilobyte_size have the same symmetries as nnpfc_complexity_info_present_flag, nnpfc_parameter_type_idc, nnpfc_log2_parameter_bit_length_minus3, nnpfc_num_parameters_idc, nnpfc_num_kmac_operations_idc, and nnpfc_total_kilobyte_size, respectively, except that the symmetries are specified for the NNPF group defined by this SEI message rather than for the NNPF defined by the NNPF SEI message. If nnpfgc_grouping_type is 1, nnpfgc_complexity_info_present_flag must be 0.

[0313] NNPFGA SEI message (Neural-network post-filter group activation SEI message) Table 28 shows an example of the NNPFGA SEI message syntax.

[0314] [Table 28] The NNPFGA SEI message activates or deactivates the possible use of a target NNPFG of the NNPF group identified by nnpfga_target_id for post-processing filtering on a set of pictures. The nnpfgc_grouping_type for the identified NNPF group must be 0 (cascade) or 1 (alternate). If nnpfgc_grouping_type is 1, each member of the group must have the same number of input pictures and NNPF output pictures. For a particular picture for which an NNPFG is activated, the target NNPFG is the NNPFG specified by the last NNPFGC SEI message with an nnpfgc_id identical to nnpfga_target_id that precedes the first VCL NAL unit of the current picture in decoding order, and the NNPFs of the target NNPFG are defined by the NNPFFC SEI messages that have nnpfc_id identical to all nnpfgc_member_id[i] values ​​of the target NNPFG, are present in the current picture unit, and precede the current picture in decoding order.

[0315] Use of this SEI message requires definitions for the following variables:

[0316] The width and height of the input picture in luma samples, here denoted by InitCroppedWidth[idx] and InitCroppedHeight[idx], respectively, of candidate input pictures with index idx ranging from 0 to numCandInputPics-1 that can be used as input to the NNPFG.

[0317] The luma sample array InitCroppedYPic[idx] and chroma sample arrays InitCroppedCbPic[idx] and InitCroppedCrPic[idx] of the candidate input picture with index idx ranging from 0 to numCandInputPics-1, if any, that can be used as input to the NNPFG.

[0318] BitDepth for the luma sample array of the candidate input picture Y BitDepth for the chroma sample array of the candidate input picture (if any) C The chroma format indicator, here denoted as ChromaFormatIdc.

[0319] When nnpfc_auxiliary_inp_idc is 1, the filtering strength control value array StrengthControlVal[idx] must contain the misses ranging from 0 to 1 for the candidate input pictures with index idx ranging from 0 to numCandInputPics-1. The candidate input picture with index 0 corresponds to the picture for which the NNPFG is activated by this NNPFGA SEI message. Candidate input pictures with index i ranging from 1 to numCandInputPics-1 precede the candidate input picture with index i-1 in output order. Let candInputPicList[0] be the list of candidate input pictures in reverse output order.

[0320] nnpfga_target_id indicates the target NNPFG associated with the current picture and specified by the NNPFGC SEI message with nnpfgc_id identical to nnpfga_target_id.

[0321] nnpfga_target_id value is 0 to 2 32 Must be in the range -2.

[0322] An NNPFGA SEI message having a characteristic value of nnpfga_target_id must not exist in the current PU unless there is an NNPFGC SEI having an nnpfgc_id that is identical to a specific value of nnpfga_target_id that exists in the current PU or the current CLVS that precedes the current PU in decoding order, and an NNPFGC SEI whose nnpfgc_grouping_type is 0.

[0323] When a PU includes both an NNPFGC SEI message having a specific value of nnpfgc_id and an NNPFGA SEI message having an nnpfga_target_id that is the same as the specific value of nnpfgc_id, the NNPFGC SEI message must precede the NNPFGA SEI message in decoding order.

[0324] nnpfga_cancel_flag, if its value is 1, indicates that the persistence of the target NNPFG established by all previous NNPFGA SEI messages with the same nnpfga_target_id as the current SEI message is cancelled, i.e., the target NNPFG will not be used any more unless activated by further NNPFGA SEI messages with the same nnpfga_target_id as the current SEI message and with nnpfga_cancel_flag set to 0. nnpfga_cancel_flag, if its value is 0, indicates that the target NNPFG is activated for use.

[0325] nnpfga_persistence_flag specifies the persistence of the target NNPFG for the current layer.

[0326] nnpfga_persistence_flag, if its value is 0, specifies that the target NNPFG can be used for post-processing filtering only for the current picture.

[0327] nnpfga_persistence_flag, if its value is 1, specifies that the target NNPFG can be used for post-processing filtering for the current picture and all subsequent pictures of the current layer in output order until one or more of the following conditions is true:

[0328] A new CLVS for the current layer is started.

[0329] The bitstream ends.

[0330] The picture of the current layer associated with the NNPFGA SEI message that has the same nnpfga_target_id as the current SEI message that is output next to the current picture in output order. Incidentally, the target NNPFG does not apply to this subsequent picture of the current layer associated with the NNPFGA SEI message that has the same nnpfga_target_id as the current SEI message.

[0331] nnpfgcTargetPictures shall be the set of pictures associated with the last NNPFGC SEI message with the same nnpfgc_id as the nnpfga_target_id that precedes the current NNPFGA SEI message in decoding order. nnpfgaTargetPictures shall be the set of pictures whose target NNPFG is activated by the current NNPFGA SEI message. It is a bitstream conformance requirement that all pictures included in nnpfgaTargetPictures shall also be included in nnpfgcTargetPictures.

[0332] nnpfga_num_filters_minus2 plus 2 indicates the number of NNPFs in the NNPFG that activates this SEI message. The nnpfga_num_filters_minus2 value shall be equal to the nnpfgc_num_members_minus2 value of the NNPFGC SEI message that has the same nnpfgc_id as the nnpfga_target_id.

[0333] If the value of nnpfga_target_base_flag[i] is 1, it indicates that the i-th NNPF of the target NNPFG is a base NNPF having the same nnpfc_id as nnpfgc_member_id[i] of the NNPFGC SEI message having the same nnpfgc_id as nnpfga_target_id. If the value of nnpfga_target_base_flag[i] is 0, it indicates that the i-th NNPF of the target NNPFG is an NNPF indicated by the last NNPFC SEI message having the same nnpfc_id as nnpfgc_member_id[i] of the NNPFGC SEI message having the same nnpfgc_id as nnpfga_target_id that precedes the first VCL NAL unit of the current picture in decoding order, and is not a repetition of the NNPFC SEI message containing the base NNPF.

[0334] If the value of nnpfga_input_all_pics_flag[i] is 1, it specifies that the input pictures for the i-th NNPF are selected from the list of candidate input pictures candInputPicList[i] without skipping. If the value of nnpfga_input_all_pics_flag[i] is 0, it specifies that the input pictures for the i-th NNPF are selected from the list of candidate input pictures candInputPicList[i] in a manner where some candidate input pictures are skipped.

[0335] nnpfga_num_input_pics_minus1[i] specifies the number of input pictures for the i-th NNPF of the target NNPFG. If it is present, nnpfga_num_input_pics_minus1[i] must be the same as nnpfc_num_input_pics_minus1 for the NNPFs with the nnpfc_id identical to nnpfgc_member_id[i] of the NNPFGC SEI message with the nnpfgc_id identical to nnpfga_target_id. If it is not present, nnpfga_num_input_pics_minus1[i] is inferred to be the same as nnpfc_num_input_pics_minus1 for the NNPFs with the nnpfc_id identical to nnpfgc_member_id[i] of the NNPFGC SEI message with the nnpfgc_id identical to nnpfga_target_id.

[0336] nnpfga_input_pic_skip_count[i][j] specifies the jth picture count to be skipped in the list of candidate input pictures candInputPicList[i] when selecting an input picture for the NNPF activated by the i-th loop entry. If nnpfga_input_pic_skip_count[i][j] is not present, it is inferred to be equal to 0 for all j values ​​ranging from 0 to nnpfga_num_input_pics_minus1[i]. numCandInputPics, which indicates the number of candidate input pictures for the NNPFG, is derived as shown in Table 29 below.

[0337] [Table 29] candInputPicList[m] is initially empty, for m in the range 1 to nnpfga_num_filters_minus2+1, and is a list of pictures in reverse output order formed in decreasing order of n in the range 0 to m-1, including each picture output by the NNPF process of the nth loop entry that does not already have a corresponding picture in candInputPicList[m], and finally including each picture in candInputPicList[0] that does not already have a corresponding picture in candInputPicList[m].

[0338] For all m values ​​ranging from 1 to nnpfga_num_filters_minus2+1, if the candidate input picture candInputPicList[m][idx] is an NNPF output picture of the nth NNPF process with an n value less than the m value, then the width and height of the candidate input picture are identical to the nnpfcOutputPicWidth and nnpfcOutputPicHeight of the NNPF output picture, respectively.

[0339] The list of input pictures inputPicList[m] for the NNPF of the m-th loop entry is derived as shown in Table 30 below.

[0340] [Table 30] It is a bitstream conformance requirement that candIdx must not exceed the number of pictures in candInputPicList[m].

[0341] It is a bitstream conformance requirement that for all values ​​in the range 1 to nnpfga_num_filters_minus2+1, the pictures present in inputPicList[m] must have the same width, height, bitrate and chroma format.

[0342] For the purpose of parsing an NNPFC SEI message with nnpfc_id equal to nnpfgc_member_id[i] of an NNPFGC SEI message with nnpfgc_id equal to nnpfga_target_id, the following variables are specified for the ith loop entry:

[0343] The variables BitDepthY, BitDepthC, and ChromaFormatIdc are used as provided to parse the message.

[0344] CroppedWidth and CroppedHeight are set equal to the width and height of the picture in inputPicList[i], respectively, in luma samples.

[0345] For each input picture k in the range 0 to nnpfga_num_input_pics_minus1[i], the following applies:

[0346] CroppedYPic[k], CroppedCbPic[k], and CroppedCrPic[k] (if present) are set equal to the corresponding sample arrays in inputPicList[i][k].

[0347] If nnpfc_auxiliary_inp_idc is 1 for an NNPF with an nnpfc_id equal to the nnpfgc_member_id[i] of the NNPFGC SEI message with an nnpfgc_id equal to the nnpfga_target_id, the following applies:

[0348] It is a bitstream conformance requirement that inputPicList[i][k] be identical to candInputPicList[0][idx] for all idx values ​​ranging from 0 to numCandInputPics-1.

[0349] StrengthControlVal[k] is set equal to InitStrengthControlVal[idx].

[0350] nnpfga_num_output_entries[i] specifies the number of nnpfga_output_flag[i][j] syntax elements present in the NNPFGA SEI message. For NNPFs with nnpfc_id equal to nnpfgc_member_id[i] of the NNPFGC SEI message with nnpfgc_id equal to nnpfga_target_id, the nnpfga_num_output_entries[i] value must be in the range from 0 to NumInpPicsInOutputTensor.

[0351] If the value of nnpfga_output_flag[i][j] is 1, it indicates that the NNPF-generated picture corresponding to the input picture with index InpIdx[j] directed to the i-th NNPF of the target NNPFG is output by the NNPF process activated by this loop entry, where the NNPF process is specified in the syntactic of the NNPFC SEI message. If the value of nnpfga_output_flag[i][j] is 0, it indicates that the NNPF-generated picture corresponding to the input picture with index InpIdx[j] directed to the i-th NNPF of the target NNPFG is not output by the NNPF process activated by this loop entry. If nnpfga_num_output_entries[i] is less than the induced NumInpPicsInOutputTensor for the i-th NNPF of the target NNPFG, then nnpfga_output_flag[i][j] is inferred to be equal to 1 for each i value ranging from nnpfga_num_output_entries[i] to NumInpPicsInOutputTensor-1.

[0352] NnpfgaOutputPicList, which is a list of pictures output by the NNPF process of NNPFG in output order, is initially empty and includes each picture output by the NNPF process of the nth loop entry that does not have a corresponding picture already present in NnpfgaOutputPicListd, and is formed in decreasing order of n in the range from 0 to nnpfga_num_filters_minus2+1.

[0353] SPTI (Source Picture Timing Information) Table 31 shows an example of SPTI syntax.

[0354] [Table 31] The SPTI SEI message indicates the temporal distance between source pictures associated with the corresponding decoded output picture before encoding. For example, for camera-captured content, the temporal distance between source pictures is the difference between the time the image sensor is exposed to generate the source picture associated with the currently decoded picture and the time the image sensor is exposed to generate the source picture associated with the previous decoded picture in output order. The information provided by the SPTI SEI message pertains only to the picture(s) starting with the picture of the current layer of the access unit, including the SPTI SEI message and all subsequent pictures of the current layer in output order based on its persistence.

[0355] If the value of spti_cancel_flag is 1, it indicates that the SPTI SEI message cancels the persistence of all previous SPTI SEI messages in the output order that are applied to the current layer. If the value of spti_cancel_flag is 0, it indicates that source picture timing information follows.

[0356] The spti_persistence_flag specifies the persistence of SPTI SEI messages for the current layer.

[0357] If the value of spti_persistence_flag is 0, it specifies that the SPTI SEI message applies only to the currently decoded picture.

[0358] spti_persistence_flag, if its value is 1, specifies that the SPTI SEI message applies to the currently decoded picture and persists for all subsequent pictures of the current layer in output order until one or more of the following conditions are true:

[0359] A new CLVS for the current layer begins.

[0360] The bitstream ends.

[0361] The picture of the current layer of the AU associated with the SPTI SEI message is output after the current picture in the output order.

[0362] If the value of spti_source_timing_equals_output_timing_flag is 1, it indicates that the timing of the source picture is the same as the timing of the corresponding decoded output picture. If the value of spti_source_timing_equals_output_timing_flag is 0, it indicates that the timing of the source picture may not be the same as the timing of the corresponding decoded output picture.

[0363] If spti_source_timing_equals_output_timing_flag is 1 and a picture timing SEI message is present for the current picture, the source picture timing can be determined by the information conveyed in the picture timing SEI message.

[0364] If the value of spti_source_type_present_flag is 1, it indicates that the syntax element spti_source_type is present in the SEI message. If the value of spti_source_type_present_flag is 0, it indicates that the syntax element spti_source_type is not present in the SEI message.

[0365] spti_source_type indicates the timing relationship between the source picture and the corresponding decoded output picture as specified in Table 32 below.

[0366] [Table 32] Here, (spti_source_type & bitMask) indicates that if its value is not 0, the timing relationship has an analysis associated with the bitmask value in Table 32. If spti_source_type is greater than 0 and (spti_source_type & bitMask) is 0, it indicates that the analysis associated with the bitmask value cannot be applied to the SPTI SEI message. If spti_source_type is 0, the timing relationship can be specified by the application.

[0367] spti_source_type values ​​MUST be in the range 0 to 127 in bitstreams that conform to this document. Values ​​from 128 to 255 are reserved for future use by ITU-T | ISO / IEC and MUST NOT be present in bitstreams that conform to this document. Decoders that conform to this document MUST ignore SPTI SEI messages with an spti_source_type between 128 and 255.

[0368] (spti_source_type & 0x04) &(spti_source_type & 0x08) values ​​must be zero (i.e., spti_source_type must not indicate high-speed imaging and time-lapse imaging simultaneously).

[0369] spti_time_scale specifies the number of time units that pass through one second. The spti_time_scale value must not be 0. For example, a time coordinate system that measures time using a 27MHz clock has an spti_time_scale of 27,000,000.

[0370] spti_num_units_in_elemental_interval specifies the number of time units of a clock running at frequency spti_time_scale Hz that corresponds to the indicated elemental source picture interval of consecutive pictures in CLVS output order.

[0371] The indicated elemental source picture interval, also represented in the variable ElementalSourcePictureInterval, is in seconds and is equal to the quotient of spti_num_units_in_elemental_interval divided by spti_time_scale. For example, to indicate a basic source picture interval equal to 0.04 seconds, spti_time_scale may be equal to 27,000,000 and spti_num_units_in_elemental_interval may be equal to 1,080,000.

[0372] spti_max_sublayers_minus_1 plus 1 specifies the maximum number of temporal sublayers for which picture interval scale factor (spti_sublayer_interval_scale_factor[i]) and synthesized flag (spti_sublayer_synthesized_picture_flag[i]) information is signaled. If spti_max_sublayers_minus_1 is not present, it is inferred to be the same as TemporalId.

[0373] spti_sublayer_interval_scale_factor[i], if present, specifies the scale factor used to determine the source picture interval of consecutive pictures in CLVS output order that have a TemporalId less than or equal to i. A value of 0 may be used to indicate that the source picture corresponding to the currently decoded output picture matches the source picture corresponding to the previously decoded output picture.

[0374] The specified source picture interval associated with output pictures having a TemporalId less than or equal to i, denoted by the variable SourcePictureInterval[i], is in seconds and is derived as shown in Table 33 below.

[0375] [Table 33] The variable temporalReversalFlag is equal to "(spti_source_type & 0x10)?1:0".

[0376] If present, spti_sublayer_synthesized_picture_flag[i] indicates that the decoded output picture belonging to the i-th temporal sub-layer is synthesized and does not correspond to an unmodified original source picture if its value is 1. spti_sublayer_synthesized_picture_flag[i] does not provide such an indication if its value is 0. If it is not present, the spti_sublayer_synthesized_picture_flag[i] value is inferred to be equal to 0.

[0377] Incidentally, if the TemporalId of an SPTI SEI message is greater than 0 and the SPTI SEI message persists for one or more pictures with lower TemporalIds, the encoder may repeat the information of the SPTI SEI message by including it in one or more SPTI SEI messages with lower TemporalIds to prevent information loss when pictures of the temporal sub-layer(s) are lost or removed.

[0378] SEI processing order SEI message Table 34 shows an example of the SEI processing order SEI message syntax.

[0379] [Table 34] SEI Processing Order SEI messages convey information indicating the preferred processing order, as determined by the encoder (i.e., content producer), for a group of types of SEI messages that can exist in the CVS.

[0380] The semantics of SEI processing order SEI messages uses the concept of SEI message type. SEI messages with different payloadType values ​​are considered to be different types of SEI messages. Furthermore, different SEI messages with the same payloadType value but distinguished by the values ​​of syntax elements in the SEI payload are considered to be different types of SEI messages. This distinction based on the values ​​of syntax elements in the SEI payload is performed by comparing the values ​​conveyed using the po_sei_prefix_data_bit[i][j] syntax element (if present) or the values ​​conveyed in SEI messages within processing order nesting SEI messages (if present). For example, NNPFC SEI messages can be distinguished as having different nnpfc_id values.

[0381] If an SEI processing order SEI message with a specific po_id value exists in all access units of the CVS, the SEI processing order SEI message with a specific po_id value must be present in the first access unit of the CVS in decoding order. The number of SEI messages specified in each SEI processing order SEI message with the same po_id value and the payloadType code of the SEI message are maintained in decoding order in the current access unit until the end of the CVS in output order.

[0382] SEI Processing Order An SEI message can carry one or more SEI prefix indicators for a particular payloadType. If present, each SEI prefix indicator is a bit string that conforms to the SEI payload syntax for the payloadType value and includes the number of complete syntax elements in the SEI payload, starting with the first syntax element. Such SEI prefix indicators must provide sufficient information to determine the specific processing order for SEI message types that have the same payloadType value but different preferred processing orders.

[0383] po_id includes an identification number for identifying the SEI processing order SEI message.

[0384] Each SEI message of an SEI message group for which preferred processing order information is provided in an SEI processing order SEI message is identified by the syntax elements po_sei_payload_type[i], po_sei_wrapping_flag[i], po_sei_processing_order[i] and, if present, po_num_bits_in_prefix_indication_minus1[i] and po_prefix_data_bit[i][j].

[0385] For each picture, there can be multiple persistent or activated SEI messages that belong to one or more groups of SEI messages.

[0386] Note that SEI message groups may be alternatives to one another, i.e., at most one group may be selected to be applied, or they may be complementary to one another, i.e., many groups may be selected and applied individually, with each group producing one output.

[0387] po_num_sei_messages_minus2 plus 2 indicates the number of types of SEI messages that the processing prefers to appear in the SEI processing order SEI message.

[0388] po_sei_wrapping_flag[i], if its value is 1, specifies that there must be one or more processing order overlapping SEI messages that have all of the following constraints:

[0389] pon_target_po_id[j] for all j values ​​is identical to po_id.

[0390] There is a kth loop entry of SEI processing order overlapped SEI messages such that the payload of the kth overlapped SEI message is equal to po_sei_payload_type[i] and pon_processing_order[k] is equal to po_sei_processing_order[i].

[0391] If po_sei_wrapping_flag[i] is 0, an SEI message having a payloadType equal to po_sei_payload_type[i] (and if po_sei_wrapping_flag[i] is 1, prefix data matching the po_sei_prefix_data_bit[i][j] value) must exist outside the processing order overlapping SEI message. However, if po_sei_wrapping_flag[i] is 0 and there is no SEI message having a payloadType equal to po_sei_payload_type[i], or if po_sei_wrapping_flag[i] is 0, po_sei_prefix_flag[i] is 1, and there is no SEI message having a payloadType equal to po_sei_payload_type[i] with prefix data matching the po_sei_prefix_data_bit[i][j] value, the following applies.

[0392] If po_sei_importance_flag[i] is 1, the decoder must ignore the entire SEI processing order SEI message.

[0393] Otherwise, the decoder must ignore all data associated with the loop variable value i.

[0394] Incidentally, if po_sei_wrapping_flag[i] has a value of 1, it transmits the SEI message within a processing order overlapping SEI message to prevent a decoder that does not process the SEI processing order SEI message from misinterpreting such an SEI message. Therefore, if po_sei_wrapping_flag[i] has a value of 1, it is intended to be used when an unintended result may occur due to a decoder that has po_sei_wrapping_flag[i] set to 0.

[0395] po_sei_importance_flag[i] indicates the importance determined by the encoder for the SEI message type with index i.

[0396] If a decoding system cannot parse or does not support the features indicated by all specified SEI messages that have po_sei_importance_flag[i] equal to 1, it must ignore the entire SEI Processing Order SEI message.

[0397] po_sei_payload_type[i] specifies the payloadType value of the i-th type of the SEI message.

[0398] po_sei_prefix_flag[i] indicates the presence of po_num_bits_in_prefix_indication_minus1[i] and some po_sei_prefix_data_bit[i][j] syntax elements if its value is 1. po_sei_prefix_flag[i] indicates the absence of such syntax elements if its value is 0.

[0399] SeiProcessingOrderSeiList is set to contain payloadType values ​​3, 4, 5, 19, 137, 142, 144, 147, 148, 149, 165, 177, 210, and 211. For each i in the range 0 to po_num_sei_messages_minus2, the po_sei_payload_type[i] value must be identical to the value in SeiProcessingOrderSeiList.

[0400] po_sei_processing_order[i] indicates the preferred order of processing of the i-th type of SEI message whose preferred processing order information is provided in the SEI processing order SEI message. For two distinct integer values ​​m and n, po_sei_processing_order[m] indicates that the SEI message type associated with index m is processed before the SEI message type associated with index n if its value is less than po_sei_processing_order[n]. And po_sei_processing_order[m] indicates that there is no preferred order of processing between the SEI message types associated with indexes m and n if its value is po_sei_processing_order[n] (e.g., they may indicate different attributes or alternative processes that may both be applied at that stage, or one may indicate an attribute and the other a process).

[0401] For i greater than 0, po_sei_processing_order[i] must be greater than or equal to po_sei_processing_order[i-1].

[0402] po_num_bits_in_prefix_indication_minus1[i] and po_sei_prefix_data_bit[i][j] have the same semantics as the num_bits_in_prefix_indication_minus1[i] and sei_prefix_data_bit[i][j] syntax elements of the SEI prefix indication SEI message, with prefix_sei_payload_type replaced by po_sei_payload_type[i], if present.

[0403] If one or more SEI processing order SEI messages with a particular po_id value exist in the CVS, then for the po_num_sei_messages_minus2 value and each i value, the po_sei_wrapping_flag[i], po_sei_prefix_flag[i], po_sei_importance_flag[i], po_sei_payload_type[i], and po_sei_processing_order[i] values ​​must be the same as other SEI processing order SEI messages in the CVS with the same po_id value.

[0404] po_byte_alignment_bit_equal_to_one must be 1.

[0405] Processing order nesting SEI message Table 35 shows an example of the processing order overlap SEI message syntax.

[0406] [Table 35] A processing order overlap SEI message contains one or more SEI messages that must be applied only to a portion of the processing chain identified by the associated SEI processing order SEI message and must not be applied in a manner that conflicts with the processing chain identified by the associated SEI processing order SEI message.

[0407] The SEI messages contained in the processing-order-overlapped SEI message are also denoted as processing-order-overlapped messages.

[0408] The persistence of all SEI messages contained in the same processing order overlapping SEI message must be the same.

[0409] pon_num_po_ids_minus1 plus 1 specifies the number of SEI processing order SEI messages associated with this processing order overlap SEI message.

[0410] pon_target_po_id[i] indicates the po_id of the i-th associated SEI processing order SEI message.

[0411] pon_num_seis_minus1 plus 1 specifies the number of processing-order-overlapped SEI messages contained in this SEI message.

[0412] pon_processing_order[i] specifies the position of the processing-order-nested SEI message contained in this SEI message within the processing order defined by the associated SEI processing order SEI message. If i is greater than 0, pon_processing_order[i] must be greater than or equal to pon_processing_order[i-1].

[0413] For each associated SEI processing order SEI message, there must be at least one i value in the range from 0 to pon_num_seis_minus1 inclusive of a processing order overlap SEI message whose associated SEI processing order SEI message has some entry k such that all of the following are true:

[0414] po_sei_processing_order[k] is the same as pon_processing_order[i].

[0415] po_sei_payload_type[k] is equal to the payloadType value of the i-th Processing-Order-Overlapped SEI message.

[0416] If po_sei_prefix_flag[k] is 1, then for i in the range 0 to po_num_bits_in_prefix_indication_minus1[k], then po_sei_prefix_data_bit[k][j] contains the same content as po_num_bits_in_prefix_indication_minus1[k] plus 1 initial bit of the SEI message payload of the i-th Processing-Order-Nested SEI message.

[0417] The i-th processing-order-overlapped SEI message shall be applied to the k-th loop entry of the associated SEI processing-order SEI message.

[0418] [ Problems with the prior art It is argued that the grouping mechanism must support at least the following grouping types: cascading grouping, alternative grouping, and parallel grouping. The mechanism works for the first two grouping types, but lacks support for activating SEI processing order SEI messages to account for parallel grouping.

[0419] A parallel grouping is a grouping in which the SEI messages in the group are not invoked / executed in cascading / sequential order, but instead are invoked in parallel. When SEI messages are invoked in cascading order, the output of the first SEI is used as the input for the second SEI message invocation. On the other hand, when two SEIs are invoked in parallel order, they both use the same input and can have independent outputs.

[0420] [Embodiment: Example The present application provides solutions to the above-mentioned problems. Each embodiment can be implemented individually or in combination with two or more other embodiments.

[0421] The embodiments proposed by the present application can be summarized as follows.

[0422] Add a SEI processing order SEI message flag to specify whether SEI messages with the same processing order value are preferred to be invoked in parallel or there is no preference for them.

[0423] Example 1 Example 1 provides an explanation for the above-mentioned Summary 1. The following Table 36 can be proposed:

[0424] [Table 36] po_num_sei_messages_minus2 plus 2 indicates the number of types of SEI messages whose preferred order of processing appears in the SEI processing order SEI message.

[0425] po_parallel_processing_enabled_flag specifies that SEI messages contained in this SEI processing order SEI message with the same processing order are preferred to be invoked in parallel if its value is 1. po_parallel_processing_enabled_flag specifies that there is no preference for the processing order of SEI messages contained in this SEI processing order SEI message with the same processing order if its value is 0.

[0426] FIG. 6 is a diagram illustrating a method for decoding video information according to an embodiment of the present disclosure.

[0427] The terms or names (e.g., names of syntax elements or names of variables) shown in Fig. 6 are merely examples, and the technical features of the present disclosure are not limited to the terms shown in Fig. 21. For example, the video information shown in Fig. 6 may include various information according to the embodiments described in the present disclosure, and may include information listed in at least one of the tables described above.

[0428] The decoding method (S600) may include the following operations. The following operations are not essential components of the decoding method according to an embodiment, and at least some of the following operations may be omitted or other operations may be added. Furthermore, the following operations may be performed by a decoding device including a memory and a processor electrically connected to the memory, for example, by the processor.

[0429] The decoding device can obtain supplemental enhancement information (SEI) processing order information (S610).

[0430] For example, a processor of a decoding apparatus may acquire video information including SEI processing order information. The video information acquired by the processor may include the SEI processing order information.

[0431] The SEI processing order information may include information regarding the processing order for a group of SEI message types that may exist in a coded video sequence (CVS) or coded layer video sequence (CLVS).

[0432] The SEI processing order information may be in various forms and may be expressed by various names. For example, the SEI processing order information may be a syntax element or a syntax structure including one or more syntax elements. Alternatively, the SEI processing order information may be a raw byte sequence payload (RBSP) including one or more syntax elements or one or more syntax structures. For example, the SEI processing order information may be expressed as sei_processing_order( ), but is not limited thereto.

[0433] The SEI processing order information may include wrapping information, payload type information, prefix information, prefix presence information, processing order information, and / or parallel processing enablement information.

[0434] The wrapping information may indicate whether the processing order overlap information includes information indicating the processing order for the SEI message type corresponding to the wrapping information. For example, a value of 1 in the wrapping information may indicate that the processing order overlap information includes information indicating the processing order for the SEI message type corresponding to the wrapping information. Alternatively, a value of 0 in the wrapping information may indicate that the processing order overlap information includes information indicating the processing order for the SEI message type corresponding to the wrapping information. However, this is not limited thereto, and alternatively, indicating that the wrapping information is a value of 1 may be interchangeable with indicating that the wrapping information is a value of 0.

[0435] The wrapping information may be in various forms and may be expressed by various names. For example, the wrapping information may be a syntax element or a syntax structure including one or more syntax elements. For example, the wrapping information as a syntax element may be a wrapping flag of one bit or a wrapping indicator of two or more bits. The wrapping information as a syntax element may be expressed as, but is not limited to, po_sei_wrapping_flag[i].

[0436] The payload type information may indicate the type of the SEI message. For example, the payload type information may specify the payloadType value of the SEI message.

[0437] The payload type information may be in various forms and may be expressed by various names. For example, the payload type information may be a syntax element or a syntax structure including one or more syntax elements. For example, the payload type information may be expressed as, but is not limited to, po_sei_payload_type[i].

[0438] The prefix information can include one or more SEI prefix indicators for the corresponding SEI message type. Each SEI prefix indicator is a bit string that conforms to the SEI payload syntax of the payloadType value and includes a number of complete syntax elements starting from the first syntax element of the SEI payload.

[0439] The prefix information may include prefix indicator bit count information and prefix data bits. The prefix indicator bit count information and prefix data bits may each be in various forms and may be expressed by various names. For example, the prefix indicator bit count information and prefix data bits may each be a syntax element or a syntax structure including one or more syntax elements. For example, the prefix indicator bit count information may be expressed as po_num_bits_in_prefix_indication_minus1[i], and the prefix data bits may be expressed as po_sei_prefix_data_bit[i], but are not limited thereto.

[0440] The prefix presence information may indicate whether prefix information corresponding to the type of the corresponding SEI message exists. In other words, the prefix presence information may indicate whether prefix indicator bit number information and prefix data bits corresponding to the type of the corresponding SEI message exist. For example, a value of 1 in the prefix presence information may indicate that prefix information corresponding to the type of the corresponding SEI message exists. Also, a value of 0 in the prefix presence information may indicate that prefix information corresponding to the type of the corresponding SEI message does not exist. However, the present invention is not limited thereto, and alternatively, a value of 1 in the prefix presence information may indicate that a value of 0 in the prefix presence information does not exist.

[0441] The prefix presence information may take various forms and be expressed by various names. For example, the prefix presence information may be a syntax element or a syntax structure including one or more syntax elements. For example, the prefix presence information as a syntax element may be a prefix presence flag of one bit or a prefix presence indicator of two or more bits. The prefix presence information as a syntax element may be expressed as, but is not limited to, po_sei_prefix_flag[i].

[0442] The processing order information may indicate a processing order corresponding to the type of the corresponding SEI message. The smaller the value of the processing order information of a specific type, the earlier the SEI message of the specific type may be processed. In other words, if the value of the processing order information of the first type is smaller than the value of the processing order information of the second type, the SEI message of the first type may be processed earlier than the SEI message of the second type.

[0443] The processing order information may be in various forms and may be expressed by various names. For example, the processing order information may be a syntax element or a syntax structure including one or more syntax elements. For example, the processing order information may be expressed as, but is not limited to, po_sei_processing_order[i].

[0444] The parallel processing enable information may indicate whether at least two SEI messages having the same processing order are invoked in parallel. For example, a value of 1 in the parallel processing enable information may indicate that at least two SEI messages having the same processing order are invoked in parallel. Alternatively, a value of 0 in the parallel processing enable information may indicate that the SEI messages are not invoked in parallel. However, the present invention is not limited to this. Alternatively, a value of 1 in the parallel processing enable flag may indicate that the SEI messages are not invoked in parallel.

[0445] Here, the SEI processing order may be determined by the group of SEI message types. SEI messages with different payloadType values ​​are considered to be different types of SEI messages. Also, different SEI messages with the same payloadType value but distinguished by the values ​​of syntax elements in the SEI payload are considered to be different types of SEI messages. Such distinction by the values ​​of syntax elements in the SEI payload may be performed based on prefix information and / or processing order overlap information.

[0446] Therefore, the parallel processing capability information may indicate whether SEI messages of the same type are invoked in parallel. Here, SEI messages with the same payload type and the same prefix information may be considered to be the same type of SEI message. Also, SEI messages with the same payload type and no prefix information may be considered to be the same type of SEI message.

[0447] The parallel processing enable information may be in various forms and may be expressed by various names. For example, the parallel processing enable information may be a syntax element or a syntax structure including one or more syntax elements. For example, the parallel processing enable information that is a syntax element may include a one-bit parallel processing enable flag or a two- or more-bit parallel processing enable indicator. The parallel processing enable information that is a syntax element may be expressed as, but is not limited to, po_parallel_processing_enabled_flag.

[0448] The image information acquired by the processor may further include processing order overlap information.

[0449] Processing order overlap information includes information about the processing order for a type of SEI message and may be associated with a particular SEI processing order information, and the processing order overlap information may apply only to the portion of the processing chain identified by the associated SEI processing order information.

[0450] The processing order nesting information may be in various forms and may be expressed by various names. For example, the processing order nesting information may be a syntax element or a syntax structure including one or more syntax elements. Alternatively, the processing order nesting information may be a raw byte sequence payload (RBSP) including one or more syntax elements or one or more syntax structures. For example, the processing order nesting information may be expressed as processing_order_nesting( ), but is not limited thereto.

[0451] The processing order overlap information may include overlap order information.

[0452] The overlap order information may specify the position of the SEI message within the processing order defined by the associated processing order information.

[0453] The overlap order information may be in various forms and may be expressed by various names. For example, the overlap order information may be a syntax element or a syntax structure including one or more syntax elements. For example, the overlap order information may be expressed as, but is not limited to, pon_processing_order[i].

[0454] As described above, the parallel processing capability information may indicate whether SEI messages of the same type are invoked in parallel. Here, SEI messages that have the same payload type, the same prefix information, and are not included in the processing order overlap information may be considered to be the same type of SEI message. Also, SEI messages that have the same payload type, the same prefix information, and are not included in the processing order overlap information may be considered to be the same type of SEI message.

[0455] The decoding device can determine the processing order for the SEI message (S620).

[0456] For example, a processor of a decoding device may determine a processing order for an SEI message based on the SEI processing order information, determine a processing order for a group of SEI message types based on the processing order information included in the SEI processing order information, and process the SEI message according to the determined processing order.

[0457] As described above, SEI messages having the same processing order are allowed to be processed in parallel, and parallel processing enablement information for allowing SEI messages to be processed in parallel may be provided. By processing SEI messages having the same processing order in parallel, there is a technical effect that SEI messages may be processed efficiently, thereby reducing the delay for processing SEI messages.

[0458] FIG. 7 is a diagram illustrating a method for encoding video information according to an embodiment of the present disclosure.

[0459] The terms or names (e.g., names of syntax elements or names of variables) shown in Figure 7 are merely examples, and the technical features of the present disclosure are not limited to the terms shown in Figure 7. For example, the video information shown in Figure 7 may include various information according to the embodiments described in the present disclosure, and may include information listed in at least one of the tables described above.

[0460] The encoding method (S700) may include the following operations. The following operations are not essential components of the encoding method according to an embodiment, and at least some of the following operations may be omitted or other operations may be added. Furthermore, the following operations may be performed by a decoding device including a memory and a processor electrically connected to the memory, for example, by the processor.

[0461] The encoding device can determine a processing order for a supplemental enhancement information (SEI) message (S710).

[0462] As an example, a processor in an encoding device can determine a processing order for groups of SEI message types.

[0463] The encoding device can generate SEI processing order information (S720).

[0464] As an example, a processor in an encoding device can generate SEI processing order information based on a processing order for a group of SEI message types.

[0465] The SEI processing order information may include information regarding the processing order for a group of SEI message types that may exist in a coded video sequence (CVS) or coded layer video sequence (CLVS).

[0466] The SEI processing order information may be in various forms and may be expressed by various names. For example, the SEI processing order information may be a syntax element or a syntax structure including one or more syntax elements. Alternatively, the SEI processing order information may be a raw byte sequence payload (RBSP) including one or more syntax elements or one or more syntax structures. For example, the SEI processing order information may be expressed as sei_processing_order( ), but is not limited thereto.

[0467] The SEI processing order information may include wrapping information, payload type information, prefix information, prefix presence information, processing order information, and / or parallel processing enablement information.

[0468] The wrapping information may indicate whether the processing order overlap information includes information indicating the processing order for the SEI message type corresponding to the wrapping information. For example, a value of 1 in the wrapping information may indicate that the processing order overlap information includes information indicating the processing order for the SEI message type corresponding to the wrapping information. Alternatively, a value of 0 in the wrapping information may indicate that the processing order overlap information includes information indicating the processing order for the SEI message type corresponding to the wrapping information. However, this is not limited thereto, and alternatively, indicating that the wrapping information is a value of 1 may be interchangeable with indicating that the wrapping information is a value of 0.

[0469] The wrapping information may be in various forms and may be expressed by various names. For example, the wrapping information may be a syntax element or a syntax structure including one or more syntax elements. For example, the wrapping information as a syntax element may be a wrapping flag of one bit or a wrapping indicator of two or more bits. The wrapping information as a syntax element may be expressed as, but is not limited to, po_sei_wrapping_flag[i].

[0470] The payload type information may indicate the type of the SEI message. For example, the payload type information may specify the payloadType value of the SEI message.

[0471] The payload type information may be in various forms and may be expressed by various names. For example, the payload type information may be a syntax element or a syntax structure including one or more syntax elements. For example, the payload type information may be expressed as, but is not limited to, po_sei_payload_type[i].

[0472] The prefix information can include one or more SEI prefix indicators for the corresponding SEI message type. Each SEI prefix indicator is a bit string that conforms to the SEI payload syntax of the payloadType value and includes a number of complete syntax elements starting from the first syntax element of the SEI payload.

[0473] The prefix information may include prefix indicator bit count information and prefix data bits. The prefix indicator bit count information and prefix data bits may each be in various forms and may be expressed by various names. For example, the prefix indicator bit count information and prefix data bits may each be a syntax element or a syntax structure including one or more syntax elements. For example, the prefix indicator bit count information may be expressed as po_num_bits_in_prefix_indication_minus1[i], and the prefix data bits may be expressed as po_sei_prefix_data_bit[i], but are not limited thereto.

[0474] The prefix presence information may indicate whether prefix information corresponding to the type of the corresponding SEI message exists. In other words, the prefix presence information may indicate whether prefix indicator bit number information and prefix data bits corresponding to the type of the corresponding SEI message exist. For example, a value of 1 in the prefix presence information may indicate that prefix information corresponding to the type of the corresponding SEI message exists. Also, a value of 0 in the prefix presence information may indicate that prefix information corresponding to the type of the corresponding SEI message does not exist. However, the present invention is not limited thereto, and alternatively, a value of 1 in the prefix presence information may indicate that a value of 0 in the prefix presence information does not exist.

[0475] The prefix presence information may take various forms and be expressed by various names. For example, the prefix presence information may be a syntax element or a syntax structure including one or more syntax elements. For example, the prefix presence information as a syntax element may be a prefix presence flag of one bit or a prefix presence indicator of two or more bits. The prefix presence information as a syntax element may be expressed as, but is not limited to, po_sei_prefix_flag[i].

[0476] The processing order information may indicate a processing order corresponding to the type of the corresponding SEI message. The smaller the value of the processing order information of a specific type, the earlier the SEI message of the specific type may be processed. In other words, if the value of the processing order information of the first type is smaller than the value of the processing order information of the second type, the SEI message of the first type may be processed earlier than the SEI message of the second type.

[0477] The processing order information may be in various forms and may be expressed by various names. For example, the processing order information may be a syntax element or a syntax structure including one or more syntax elements. For example, the processing order information may be expressed as, but is not limited to, po_sei_processing_order[i].

[0478] The parallel processing enable information may indicate whether at least two SEI messages having the same processing order are invoked in parallel. For example, a value of 1 in the parallel processing enable information may indicate that at least two SEI messages having the same processing order are invoked in parallel. Alternatively, a value of 0 in the parallel processing enable information may indicate that the SEI messages are not invoked in parallel. However, the present invention is not limited to this. Alternatively, a value of 1 in the parallel processing enable flag may indicate that the SEI messages are not invoked in parallel.

[0479] Here, the SEI processing order may be determined by the group of SEI message types. SEI messages with different payloadType values ​​are considered to be different types of SEI messages. Also, different SEI messages with the same payloadType value but distinguished by the values ​​of syntax elements in the SEI payload are considered to be different types of SEI messages. Such distinction by the values ​​of syntax elements in the SEI payload may be performed based on prefix information and / or processing order overlap information.

[0480] Therefore, the parallel processing capability information may indicate whether SEI messages of the same type are invoked in parallel. Here, SEI messages with the same payload type and the same prefix information may be considered to be the same type of SEI message. Also, SEI messages with the same payload type and no prefix information may be considered to be the same type of SEI message.

[0481] The parallel processing enable information may be in various forms and may be expressed by various names. For example, the parallel processing enable information may be a syntax element or a syntax structure including one or more syntax elements. For example, the parallel processing enable information that is a syntax element may include a one-bit parallel processing enable flag or a two- or more-bit parallel processing enable indicator. The parallel processing enable information that is a syntax element may be expressed as, but is not limited to, po_parallel_processing_enabled_flag.

[0482] The processor of the encoding device may additionally generate processing order overlap information based on the processing order for the group of types of SEI messages.

[0483] Processing order overlap information includes information about the processing order for a type of SEI message and may be associated with a particular SEI processing order information, and the processing order overlap information may apply only to the portion of the processing chain identified by the associated SEI processing order information.

[0484] The processing order nesting information may be in various forms and may be expressed by various names. For example, the processing order nesting information may be a syntax element or a syntax structure including one or more syntax elements. Alternatively, the processing order nesting information may be a raw byte sequence payload (RBSP) including one or more syntax elements or one or more syntax structures. For example, the processing order nesting information may be expressed as processing_order_nesting( ), but is not limited thereto.

[0485] The processing order overlap information may include overlap order information.

[0486] The overlap order information may specify the position of the SEI message within the processing order defined by the associated processing order information.

[0487] The overlap order information may be in various forms and may be expressed by various names. For example, the overlap order information may be a syntax element or a syntax structure including one or more syntax elements. For example, the overlap order information may be expressed as, but is not limited to, pon_processing_order[i].

[0488] As described above, the parallel processing capability information may indicate whether SEI messages of the same type are invoked in parallel. Here, SEI messages that have the same payload type, the same prefix information, and are not included in the processing order overlap information may be considered to be the same type of SEI message. Also, SEI messages that have the same payload type, the same prefix information, and are not included in the processing order overlap information may be considered to be the same type of SEI message.

[0489] The encoding device may encode the video information including the SEI processing order information (S730).

[0490] As an example, a processor of an encoding device may encode video information including SEI processing order information.

[0491] As described above, SEI messages having the same processing order are allowed to be processed in parallel, and parallel processing enablement information for allowing SEI messages to be processed in parallel may be provided. By processing SEI messages having the same processing order in parallel, there is a technical effect that SEI messages can be processed efficiently and delays for processing SEI messages in advance are reduced.

[0492] The video information including the SEI processing order information encoded by the encoding method S700 may be stored in a computer-readable storage medium, and may be transmitted via a transmission unit and / or a transmission medium.

[0493] FIG. 8 exemplarily illustrates a structural diagram of a content streaming system to which the embodiments of this document are applied.

[0494] A content streaming system to which the embodiments of this document are applied can broadly include an encoding server, a streaming server, a web server, a media repository, a user device, and a multimedia input device.

[0495] The encoding server compresses content input from a multimedia input device such as a smartphone, camera, camcorder, etc. into digital data to generate a bitstream and transmits the bitstream to the streaming server. As another example, if a multimedia input device such as a smartphone, camera, camcorder, etc. directly generates a bitstream, the encoding server may be omitted.

[0496] The bitstream can be generated by an encoding method or a bitstream generation method to which an embodiment of this document is applied, and the streaming server can temporarily store the bitstream in the process of transmitting or receiving the bitstream.

[0497] The streaming server transmits multimedia data to a user device based on a user request via a web server, and the web server acts as an intermediary to inform the user of available services. When a user requests a desired service from the web server, the web server transmits the request to the streaming server, which then transmits the multimedia data to the user. The content streaming system may include a separate control server, which controls commands and responses between devices in the content streaming system.

[0498] The streaming server can receive content from a media repository and / or an encoding server. For example, if content is received from the encoding server, the content can be received in real time. In this case, the streaming server can store the bitstream for a certain period of time to provide a smooth streaming service.

[0499] Examples of the user devices include mobile phones, smartphones, laptop computers, digital broadcasting terminals, personal digital assistants (PDAs), portable multimedia players (PMPs), navigation systems, slate PCs, tablet PCs, ultrabooks, wearable devices (e.g., smartwatches, smart glasses, and head-mounted displays (HMDs)), digital TVs, desktop computers, and digital signage.

[0500] Each server in the content streaming system can be operated as a distributed server, and in this case, data received by each server can be processed in a distributed manner.

[0501] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that cause operations according to the methods of various embodiments to be performed on a device or computer, and non-transitory computer-readable media on which such software or instructions are stored and executable on a device or computer.

[0502] [Industrial Applicability] The embodiments of the present disclosure can be used to encode / decode images.

[0503] [Claims at the time of international application] [Claim 1] A method for decoding video information, comprising: obtaining video information including supplemental enhancement information (SEI) processing order information including a processing order for a group of types of SEI messages; determining a processing order for a type group of the SEI message based on the SEI processing order information; The SEI processing order information includes payload type information indicating a type of an SEI message, prefix existence information indicating whether prefix information of the SEI message exists (or not), and processing order information indicating a processing order according to the type of the SEI message, The method, wherein the SEI processing order information further includes parallel processability information indicating whether (or not) at least two SEI messages having the same processing order are invoked in parallel. [Claim 2] The value of the parallel processing capability information being 1 indicates that at least two SEI messages having the same processing order are invoked in parallel; The method of claim 1 , wherein a value of the parallel processing capability information equal to 0 indicates that the SEI message is not invoked in parallel. [Claim 3] The method of claim 1 , wherein at least two SEI messages of the same type and having the same prefix information have the same processing order. [Claim 4] The method of claim 1 , wherein at least two SEI messages of the same type and without prefix information have the same processing order. [Claim 5] The method of claim 1 , wherein the video information further includes processing order overlap information including position information of a specific SEI message within a processing order defined by the SEI processing order information. [Claim 6] The method of claim 5, wherein at least two SEI messages that are the same type, have the same prefix information, and are not included in the processing order overlap information have the same processing order. [Claim 7] The method of claim 5, wherein at least two SEI messages that are the same type, have no prefix information, and are not included in the processing order overlap information have the same processing order. [Claim 8] 1. A method of encoding video information, comprising: Determine a processing order for groups of supplemental enhancement information (SEI) message types; generating SEI processing order information including a processing order for a group of SEI message types based on the processing order; encoding the video information including the SEI processing order information; The SEI processing order information includes payload type information indicating a type of an SEI message, prefix existence information indicating whether prefix information of the SEI message exists (or not), and processing order information indicating a processing order according to the type of the SEI message, The method, wherein the SEI processing order information further includes parallel processability information indicating whether (or not) at least two SEI messages having the same processing order are invoked in parallel. [Claim 9] 1. A method for storing a bitstream of video information, comprising: obtaining video information including supplemental enhancement information (SEI) processing order information including a processing order for a group of types of SEI messages; storing data including the bitstream of video information on a computer-readable storage medium; The SEI processing order information includes payload type information indicating a type of an SEI message, prefix existence information indicating whether prefix information of the SEI message exists (or not), and processing order information indicating a processing order according to the type of the SEI message, The method, wherein the SEI processing order information further includes parallel processability information indicating whether (or not) at least two SEI messages having the same processing order are invoked in parallel. [Claim 10] 1. A method for transmitting a bitstream of video information, comprising: obtaining video information including supplemental enhancement information (SEI) processing order information including a processing order for a group of types of SEI messages; transmitting data including a bitstream of said video information; The SEI processing order information includes payload type information indicating a type of an SEI message, prefix existence information indicating whether prefix information of the SEI message exists (or not), and processing order information indicating a processing order according to the type of the SEI message, The method, wherein the SEI processing order information further includes parallel processability information indicating whether (or not) at least two SEI messages having the same processing order are invoked in parallel.

Claims

1. A method for decoding video information, comprising: Obtaining video information including supplemental enhancement information (SEI) processing order information including a processing order for a group of types of SEI messages; determining a processing order for the type group of the SEI message based on the SEI processing order information; The SEI processing order information includes payload type information indicating a type of an SEI message, prefix presence information indicating whether prefix information of the SEI message exists, and processing order information indicating a processing order according to the type of the SEI message, The method, wherein the SEI processing order information further includes parallel processability information indicating whether at least two SEI messages having the same processing order are invoked in parallel.

2. The value of the parallel processing capability information being 1 indicates that at least two SEI messages having the same processing order are invoked in parallel; The method of claim 1 , wherein a value of the parallel processing capability information equal to 0 indicates that the SEI message is not invoked in parallel.

3. The method of claim 1 , wherein at least two SEI messages of the same type and having the same prefix information have the same processing order.

4. The method of claim 1 , wherein at least two SEI messages of the same type and without prefix information have the same processing order.

5. The method of claim 1 , wherein the video information further includes processing order overlap information including position information of a specific SEI message within a processing order defined by the SEI processing order information.

6. The method of claim 5 , wherein at least two SEI messages that are the same type, have the same prefix information, and are not included in the processing order overlap information have the same processing order.

7. The method of claim 5 , wherein at least two SEI messages that are the same type, have no prefix information, and are not included in the processing order overlap information have the same processing order.

8. 1. A method of encoding video information, comprising: determining a processing order for a group of supplemental enhancement information (SEI) message types; generating SEI processing order information including a processing order for a group of SEI message types based on the processing order; encoding the video information including the SEI processing order information; The SEI processing order information includes payload type information indicating a type of an SEI message, prefix presence information indicating whether prefix information of the SEI message exists, and processing order information indicating a processing order according to the type of the SEI message, The method, wherein the SEI processing order information further includes parallel processability information indicating whether at least two SEI messages having the same processing order are invoked in parallel.

9. 1. A method for storing a bitstream of video information, comprising: Obtaining video information including supplemental enhancement information (SEI) processing order information including a processing order for a group of types of SEI messages; storing data including the bitstream of video information on a computer-readable storage medium; The SEI processing order information includes payload type information indicating a type of an SEI message, prefix presence information indicating whether prefix information of the SEI message exists, and processing order information indicating a processing order according to the type of the SEI message, The method, wherein the SEI processing order information further includes parallel processability information indicating whether at least two SEI messages having the same processing order are invoked in parallel.

10. 1. A method for transmitting a bitstream of video information, comprising: Obtaining video information including supplemental enhancement information (SEI) processing order information including a processing order for a group of types of SEI messages; transmitting data including a bitstream of said video information; The SEI processing order information includes payload type information indicating a type of an SEI message, prefix presence information indicating whether prefix information of the SEI message exists, and processing order information indicating a processing order according to the type of the SEI message, The method, wherein the SEI processing order information further includes parallel processability information indicating whether at least two SEI messages having the same processing order are invoked in parallel.

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