Video decoder initialization information

Abstract

A mechanism of processing video data is disclosed. Video decoder initialization information is signaled between an encoder and a decoder. The video decoder initialization information includes a series of initialization parameters. A conversion between visual media data and a visual media data file is performed based on the series of initialization parameters.

Description

[0001] Cross-references to related applications

[0002] This patent application claims the benefit of international application No. PCT / CN2020 / 138662, filed December 23, 2020, entitled “Video Decoder Initialization Information”, and international application No. PCT / CN2021 / 070411, filed January 6, 2021, entitled “Video Decoder Initialization Information”, which are incorporated herein by reference. Technical Field

[0003] This patent relates to the generation, storage, and consumption of digital audio and video media information in file formats. Background Technology

[0004] Digital video consumes the largest share of bandwidth in the internet and other digital communication networks. As the number of connected user devices capable of receiving and displaying video increases, the bandwidth demand for digital video is expected to continue to grow. Summary of the Invention

[0005] The first aspect relates to a method for processing video data, comprising: signaling to video decoder initialization information containing a series of initialization parameters; and performing a conversion between visual media data and a visual media data file based on the series of initialization parameters.

[0006] Alternatively, in any of the foregoing aspects, another implementation of that aspect provides that decoder initialization information is signaled in at least one Decoding Capability Information (DCI) Network Abstraction Layer (NAL) unit in at least one bitstream.

[0007] Alternatively, in any of the foregoing aspects, another implementation of that aspect provides that decoder initialization information is signaled in at least one decoder initialization information (DII) supplemental enhancement information (SEI) message in at least one bitstream.

[0008] Alternatively, in any of the foregoing aspects, another implementation of that aspect provides that the DII SEI message needs to exist in the first access unit AU of the corresponding bit stream.

[0009] Alternatively, in any of the foregoing aspects, another implementation of that aspect provides that decoder initialization information is signaled in an International Organization for Standardization (ISO) Basic Media File Format (ISOBMFF) file in a file-level frame, a movie-level frame, at least one track-level frame, or a combination thereof.

[0010] Optionally, in any of the foregoing aspects, another implementation of that aspect provides that decoder initialization information is signaled in a file-level metadata frame, a movie-level metadata frame, a movie header frame, a sample description frame, a track header frame, a track group frame, a track-level metadata frame, or a combination thereof.

[0011] Alternatively, in any of the foregoing aspects, another implementation of that aspect provides that decoder initialization information is signaled in a Dynamic Adaptive Streaming (DASH) Media Presentation Description (MPD) based on Hypertext Transfer Protocol.

[0012] Alternatively, in any of the foregoing aspects, another implementation of that aspect provides that decoder initialization information is signaled in an adaptive set, representation, or combination thereof.

[0013] Alternatively, in any of the foregoing aspects, another implementation of that aspect provides that decoder initialization information is signaled in the Real-Time Transport Protocol (RTP) header extension.

[0014] Alternatively, in any of the foregoing aspects, another implementation of that aspect provides that decoder initialization information is signaled as part of a Session Description Protocol (SDP) proposal, an SDP response, or a combination thereof.

[0015] Optionally, in any of the foregoing aspects, another implementation of that aspect provides: decoder initialization information including the maximum number of decoded images (maxDecPics) stored in the decoded image buffer (DPB) when decoding the bitstream, the maximum decoded image width (maxDecPicW) of the encoded and decoded images in the bitstream, the maximum decoded image height (maxDecPicH) of the encoded and decoded images in the bitstream, or a combination thereof.

[0016] Optionally, in any of the foregoing aspects, another implementation of that aspect provides: decoder initialization information including indications of inter-layer prediction, reference image resampling, surround motion compensation, motion vector prediction from the reference image, palette encoding / decoding mode, adaptive color transformation, intra-frame block copying, adaptive loop filter (ALF) adaptive parameter set (APS) NAL unit, luminance mapping with chroma scaling (LMCS) APS NAL unit, scaling list APSNAL unit, or combinations thereof in the corresponding bitstream.

[0017] Alternatively, in any of the foregoing aspects, another implementation of that aspect provides that the decoder initialization information includes an indication of the maximum image sequence count between the current image and the corresponding reference image.

[0018] Optionally, in any of the foregoing aspects, another implementation of that aspect provides: decoder initialization information including an indication of the maximum color format, maximum bit depth, maximum codec image buffer size, smallest decoding unit (CU) size, scaling calculation information, or a combination thereof.

[0019] Alternatively, in any of the foregoing aspects, another implementation of that aspect provides: decoder initialization information including instructions for the use of deblocking, padding, sub-image segmentation, strip segmentation, slice segmentation, surround motion compensation, reference image resampling, long-term reference images, or combinations thereof.

[0020] Optionally, in any of the foregoing aspects, another implementation of that aspect provides: decoder initialization information including the maximum layer that all codec video sequences (CVS) of the corresponding bitstream conform to, the maximum level that all CVSs of the corresponding bitstream conform to, or a combination thereof.

[0021] Alternatively, in any of the foregoing aspects, another implementation of that aspect provides: decoder initialization information including instructions for a video codec used to perform conversion between visual media data and visual media data files.

[0022] Alternatively, in any of the foregoing aspects, another implementation of that aspect provides: decoder initialization information including the grade that all bitstreams conform to.

[0023] Alternatively, in any of the foregoing aspects, another implementation of that aspect provides that the method is executed by the decoder, and the decoder is reinitialized when the grade, layer, and level (PTL) information is changed.

[0024] Alternatively, in any of the foregoing aspects, another implementation of that aspect provides that the method is executed by the decoder, and the decoder is reinitialized when at least one of the general timing parameter and the assumed reference decoder (HRD) parameter is changed.

[0025] Alternatively, in any of the foregoing aspects, another implementation of that aspect is provided: the conversion includes generating a visual media data file based on the visual media data.

[0026] Alternatively, in any of the foregoing aspects, another implementation of that aspect provides that the conversion includes parsing a visual media data file to obtain visual media data.

[0027] The second aspect relates to an apparatus for processing video data, including a processor and a non-transitory memory having instructions thereon, wherein the instructions, when executed by the processor, cause the processor to perform any of the methods of the foregoing aspects.

[0028] The third aspect relates to a non-transitory computer-readable medium, including a computer program product for use by a video codec apparatus, the computer program product including computer-executable instructions stored on the non-transitory computer-readable medium, such that when the computer-executable instructions are executed by a processor, the video codec apparatus performs any of the methods described above.

[0029] For clarity, any of the foregoing embodiments may be combined with any one or more other foregoing embodiments to form new embodiments within the scope of this disclosure.

[0030] These and other features will become clearer from the following detailed description taken in conjunction with the accompanying drawings and claims. Attached Figure Description

[0031] To gain a more complete understanding of this disclosure, reference is now made to the following brief description in conjunction with the accompanying drawings and detailed specifications, wherein the same reference numerals represent the same parts.

[0032] Figure 1 This is a protocol diagram illustrating an example mechanism used to establish a communication session with SDP;

[0033] Figure 2 This is a protocol diagram of an example mechanism for performing video streaming based on DASH;

[0034] Figure 3 This is a schematic diagram illustrating the MPD description of video used in DASH;

[0035] Figure 4 A diagram illustrating media files stored in ISOBMFF;

[0036] Figure 5 This is a schematic diagram of a bitstream containing encoded visual media data;

[0037] Figure 6 This is a block diagram illustrating an example video processing system;

[0038] Figure 7 This is a block diagram of an example video processing device;

[0039] Figure 8 This is a flowchart of an example method for video processing;

[0040] Figure 9 This is a block diagram illustrating an example video encoding and decoding system;

[0041] Figure 10 This is a block diagram illustrating an example encoder;

[0042] Figure 11 This is a block diagram illustrating an example decoder; and

[0043] Figure 12 This is a schematic diagram of an example encoder. Detailed Implementation

[0044] First, it should be understood that although illustrative implementations of one or more embodiments are provided below, the disclosed systems and / or methods can be implemented using any number of techniques, whether currently known or yet to be developed. This disclosure should not be limited in any way to the exemplary implementations, drawings, and techniques shown below, including the exemplary designs and implementations shown and described herein, but modifications can be made within the full scope of the appended claims and their equivalents.

[0045] The Multi-Functional Video Codec (VVC), also known as H.266, uses the term in some descriptions for ease of understanding only and not to limit the scope of the disclosed technology. Therefore, the techniques described herein are also applicable to other video codec protocols and designs. In this document, textual edits relative to the VVC specification or the current draft of the International Organization for Standardization (ISO) Basic Media File Format (ISOBMFF) file format specification are indicated by strikethrough to represent undo text and bold italics to represent added text.

[0046] This patent relates to video codecs, video file formats, video signaling notifications, and video applications. Specifically, this document relates to signaling notifications of video decoder initialization information and the use of such signaling notifications for decoder initialization and re-initialization. This can help avoid and / or reduce the occurrence of video decoder re-initialization during application sessions, thereby helping to improve the user experience. The disclosed examples can be applied, alone or in various combinations, to video bitstreams encoded and decoded by any codec such as the VVC standard, and to any video file format such as the VVC video file format. The disclosed examples can also be used in various video applications, including streaming applications based on Dynamic Adaptive Streaming over HTTP (DASH) and session applications using signaling notifications based on the Session Description Protocol (SDP).

[0047] This disclosure includes the following abbreviations: Adaptive Color Transformation (ACT), Adaptive Loop Filter (ALF), Adaptive Motion Vector Resolution (AMVR), Adaptive Parameter Set (APS), Access Unit (AU), Access Unit Separator (AUD), Advanced Video Codec (Rec.ITU-T H.264|ISO / IEC 14496-10) (AVC), Bidirectional Prediction (B), Bidirectional Prediction with CU-level Weights (BCW), Bidirectional Optical Flow (BDOF), Block-based Incremental Pulse Codec Modulation (BDPCM), Buffer Period (BP), Context-based Adaptive Binary Arithmetic Codec (CABAC), Codec Block (CB), Constant Bit Rate (CBR), Cross-Component Adaptive Loop Filter (CCALF), Codec Picture Buffer (CPB), Clean Random Access (CRA), Cyclic Redundancy Check (CRC), Codec Tree Block (CTB), Codec Tree Unit (CTU), Codec Unit (CU), Codec Video Sequence (C VS), Decoding Capability Information (DCI), Decoding Initialization Information (DII), Decoding Picture Buffer (DPB), Dependent Random Access Point (DRAP), Decoding Unit (DU), Decoding Unit Information (DUI), Exponential Golomb (EG), k-order Exponential Golomb (EGk), End of Bitstream (EOB), End of Sequence (EOS), Padding Data (FD), First-In-First-Out (FIFO), Fixed Length (FL), Green, Blue and Red (GBR), General Constraint Information (GCI), Gradual Decoding Refresh (GDR), Geometric Segmentation Mode (GPM), High-Efficiency Video Coding (also known as Rec. ITU-T H).265|ISO / IEC 23008-2)(HEVC), Hypothetical Reference Decoder (HRD), Hypothetical Stream Scheduler (HSS), Intra-Frame (I), Intra-Frame Block Copy (IBC), Instant Decode Refresh (IDR), Inter-Layer Reference Picture (ILRP), Intra-Frame Random Access Point (IRAP), Low-Frequency Inseparable Transform (LFNST), Least Probable Symbol (LPS), Least Significant Bit (LSB), Long-Term Reference Picture (LTRP), Luminance Map with Chroma Scaling (LMCS), Matrix-Based Intra-Frame Prediction (MIP), Most Probable Symbol (MPS), Most Significant Bit (MSB), Multiple Transform Selection (MTS), Motion Vector Prediction (MVP), Network Abstraction Layer (NAL), Output Layer Set (OLS), Operation Point (OP), Operation Point Information (OPI), Prediction (P), Picture Header (PH), Picture Order Count (POC), Picture Parameter Set (PPS), Predictive Refinement Using Optical Flow (PROF), Picture Timing (PT), Picture Unit (PU), Quantization Parameter (QP), Random Access Decodable Pre-Picture (RADL), Random Access Skip Pre-Picture (RASL), Raw Byte Sequence Payload (RBSP), Red, Green, and Blue (RGB), Reference Picture List (RPL), Sample Adaptive Offset (SAO), Sample Aspect Ratio (SAR), Supplemental Enhancement Information (SEI), Strip Header (SH), Subpicture Level Information (SLI), Data Bit String (SODB), Sequence Parameter Set (SPS), Short-Term Reference Picture (STRP), Stepped Temporal Sublayer Access (STSA), Truncated Rice (TR), Variable Bit Rate (VBR), Video Coding Layer (VCL), Video Parameter Set (VPS), Multifunctional Supplemental Enhancement Information (also known as Rec.ITU-T) H.274|ISO / IEC 23002-7 (VSEI), Video Availability Information (VUI), and Multi-Function Video Codec (also known as Rec.ITU-T H.266|ISO / IEC 23090-3) (VVC).

[0048] Video codec standards have primarily evolved through the development of ITU-T and ISO / IEC standards. ITU-T developed the H.261 and H.263 standards, while ISO / IEC developed the MPEG-1 and MPEG-4 Visual standards. The two organizations jointly developed the H.262 / MPEG-2 video standard, the H.264 / MPEG-4 Advanced Video Codec (AVC) standard, and the H.265 / HEVC standard. Starting with H.262, video codec standards are based on a hybrid video codec architecture, utilizing temporal prediction plus transform coding. To explore further video codec technologies beyond HEVC, the Joint Video Exploration Team (JVET) was jointly established by the Video Codec Experts Group (VCEG) and MPEG. JVET adopted many methods and incorporated them into reference software called the Joint Exploration Model (JEM). When the Multifunctional Video Codec (VVC) project was officially launched, JVET was later renamed the Joint Video Experts Team (JVET). VVC is a codec standard aiming to reduce the bitrate by 50% compared to HEVC. VVC has been finalized by JVET.

[0049] The Basic Video Codec (EVC) standard (ISO / IEC 23094-1) is another video codec standard developed by MPEG.

[0050] The following discusses Decoding Capability Information (DCI) in VVC. A DCI NAL unit is part of the video codec bitstream, which contains bitstream level profiles, layers, and levels (PTL) information. A DCI NAL unit includes one or more PTL syntax structures that can be used during session negotiation between the sender and receiver of the VVC bitstream. When a DCI NAL unit is present in a VVC bitstream, each Output Layer Set (OLS) in the bitstream's CVS should conform to the PTL information carried in at least one PTL structure within the DCI NAL unit.

[0051] In AVC and HEVC, PTL information used for session negotiation is available in the SPS (for HEVC and AVC) and VPS (for HEVC layered extensions). This design of transmitting PTL information for session negotiation in HEVC and AVC can have some drawbacks because the scope of the SPS and VPS is within the CVS, not the entire bitstream. Therefore, sender-receiver session initiation may encounter reinitialization during bitstream streaming of each new CVS. DCI solves this problem because the DCU NAL unit carries bitstream-level information. Therefore, conformity to the indicated decoding capability can be guaranteed until the end of the bitstream.

[0052] File format standards are as follows. Media streaming applications are typically based on Internet Protocol (IP), Transmission Control Protocol (TCP), and Hypertext Transfer Protocol (HTTP) transmission methods, and often rely on file formats such as ISOBMFF. One such streaming system is HTTP-based Dynamic Adaptive Streaming (DASH). Video can be encoded in video formats such as AVC and / or HEVC. The encoded video can be encapsulated in ISOBMFF tracks and contained in DASH representations and segments. For content selection purposes, important information about the video bitstream, such as grade, layer, and level, can be presented as file format-level metadata and / or in the DASH Media Presentation Description (MPD). For example, this information can be used to select appropriate media segments for initialization at the start of a streaming session and for stream adaptation during the streaming session.

[0053] Similarly, when using an image format with ISOBMFF, image format-specific file format specifications can be used, such as the AVC image file format and the HEVC image file format. MPEG is developing the VVC video file format, which is an ISOBMFF-based file format for storing VVC video content. MPEG is also developing an ISOBMFF-based VVC image file format for storing image content encoded and decoded using VVC.

[0054] The following discusses DASH. DASH supports multiple representations of video and / or audio data for creating multimedia content. Different representations can correspond to different codec characteristics, such as different levels or grades of video codec standards, different bitrates, different spatial resolutions, etc. DASH uses a list of such representations defined in a Media Presentation Description (MPD) data structure. A media presentation can correspond to a structured data set accessible to DASH streaming client devices. DASH streaming client devices can request and download media data information to present streaming services to users on the client devices. Media presentations can be described in the MPD data structure, which may include updates to the MPD.

[0055] A media presentation may consist of a sequence of one or more cycles. Each cycle may extend to the beginning of the next cycle, or, in the case of the last cycle, to the end of the media presentation. Each cycle may contain one or more representations of the same media content. A representation may be one of several alternative encoded versions of audio, video, timed text, or other such data. These representations may differ depending on the encoding type, such as the bitrate, resolution, and / or codec of video data, and the bitrate, language, and / or codec of audio data. The term "representation" can be used to refer to a portion of encoded audio or video data that corresponds to a specific cycle of multimedia content and is encoded in a particular manner.

[0056] A representation for a specific period can be assigned to a group indicated by an attribute in the MPD, which indicates the adaptive set to which the representation belongs. Representations within the same adaptive set are generally considered interchangeable because client devices can dynamically and seamlessly switch between these representations, for example, to perform bandwidth adaptation. For instance, each representation of video data for a specific period can be assigned to the same adaptive set. Any representation can be selected for decoding to render the media data, such as video or audio data, of the multimedia content for the corresponding period. In some examples, the media content within a period can be represented by a single representation from group 0 (if present) or a combination of at most one representation from each non-zero group. The timing data for each representation of a period can be represented relative to the start time of the period.

[0057] A representation may include one or more segments. Each representation may include an initialization segment, or each segment of a representation may be self-initialized. If present, the initialization segment may contain initialization information for accessing the representation. Typically, the initialization segment does not contain media data. Segments may be uniquely referenced by identifiers such as Uniform Resource Locators (URLs), Uniform Resource Names (URNs), or Uniform Resource Identifiers (URIs). The MPD may provide an identifier for each segment. In some examples, the MPD may also provide byte ranges in the form of range attributes, which may correspond to data within segments of a file accessible via a URL, URN, or URI.

[0058] Different representations can be selected to retrieve different types of media data substantially simultaneously. For example, a client device can select audio representations, video representations, and timed text representations to retrieve segments from them. In some examples, the client device can select a specific adaptive set to perform bandwidth adaptation. For example, the client device can select an adaptive set that includes video representations, an adaptive set that includes audio representations, and / or an adaptive set that includes timed text. The client device can also select an adaptive set for certain types of media (e.g., video) and directly select a representation for other types of media (e.g., audio and / or timed text).

[0059] The following steps illustrate a sample DASH streaming process. The client acquires the MPD (Multi-Level Display). The client estimates the downlink bandwidth. The client selects a video representation and an audio representation based on the estimated downlink bandwidth and codecs, decoding capabilities, display size, audio language settings, etc. Unless the end of media rendering is reached, the client continues to request media segments from the selected representations and presents the streaming content to the user. The client continuously estimates the downlink bandwidth. When the bandwidth changes significantly (e.g., becomes lower), the client selects a different video representation to match the newly estimated bandwidth and continues to request media segments from the newly selected representation.

[0060] The following discusses the Real-Time Video Transport Protocol (RTP) payload format and Session Description Protocol (SDP). For any video codec used in a video application, such as VVC using RTP, the RTP payload format should be specified. Additionally, the mechanism for notifying media type parameters using SDP signaling should also be specified. The RTP payload format of a video codec primarily specifies how the encoded and decoded video bitstream is encapsulated in RTP packets and RTP streams. IETF RFC 6184, RFC 6190, and RFC 7798 specify the RTP payload formats for AVC, SVC, and HEVC, respectively. The IETF is developing an RTP payload for VVC.

[0061] The following are example technical problems addressed by the disclosed technical solutions. Current video codec and communication standards and systems lack a mechanism for signaling to notify video decoder initialization information. For example, in adaptive streaming, streaming clients often request to switch to different bitstreams with different spatial resolutions to adapt to changing network conditions, such as varying bandwidth. Different bitstreams may be stored in different File Format (FF) tracks and encapsulated in different DASH representations within the same adaptive set. Therefore, such bitstream switching typically involves switching between FF tracks and DASH representations. In many cases, the switched bitstream has the same codec (e.g., VVC) and the same profile (e.g., VVC Master 10 profile) as the original bitstream. Depending on the availability of other information, such as the maximum spatial resolution and the decoder implementation, the decoder can be reinitialized when the spatial resolution changes, especially when it increases. Decoder initialization or reinitialization typically takes 100-200 milliseconds (ms). In some examples, initialization or reinitialization may take as little as 16 milliseconds, depending on various factors, including memory allocation time, secure / insecure, mapping time, memory fragmentation of Double Data Rate (DDR) memory, internal fragmentation of the System Memory Management Unit (SMMU), etc. Therefore, decoder reinitialization can interrupt streaming sessions and affect playback continuity. Thus, signaling information to the video decoder regarding decoder initialization is useful, allowing video decoder reinitialization to be avoided or minimized as much as possible within the application session to maximize user experience.

[0062] This document discloses a mechanism for addressing one or more of the problems listed above. As a specific example, a decoder can be configured to dynamically select from a set of tracks containing bitstreams for streaming video data according to the DASH protocol. In such an example, the decoder can select segments from tracks based on constantly changing network conditions. When the settings used to decode the current track segment are insufficient to support decoding the next track segment in the newly selected track, decoder reinitialization can be triggered. The disclosed mechanism supports minimizing and / or eliminating such reinitialization. For example, a codec or intermediate storage server can signal decoder initialization information to the decoder. Decoder initialization information can describe memory constraints, codec tools, and / or other settings used when encoding each of a set of related tracks and / or bitstreams. The decoder can use this information to mitigate reinitialization. For example, the decoder can initialize based on the most stringent set of memory constraints, codec tools, and / or settings used by various tracks / bitstreams. Thus, the most stringent settings support decoding each track / bitstream the decoder might select. As a specific example, each track can contain picture bitstreams encoded and decoded at different resolutions. The decoder can select different tracks to increase or decrease the resolution based on current network conditions. During decoding, the decoder allocates memory in the decoded image buffer to store reference images used in inter-frame prediction. The amount of memory allocated may vary depending on the resolution. Therefore, the decoder can select memory allocation parameters associated with the highest resolution track during initialization. This ensures sufficient memory allocation to decode any track, thus eliminating the need for reinitialization. Many different parameters can be used to encode and decode the bitstream to be included in the tracks. A non-exhaustive list of parameters that can be used as decoder initialization information is provided below.

[0063] Depending on the example implementation, decoder initialization information may be signaled at different locations. For example, decoder initialization information may be signaled at the bitstream level, such as in DCI NAL units and / or DII SEI messages within one or more bitstreams. In another example, decoder initialization information may be signaled at the file format level, such as in a file-level box, a movie-level box, and / or a track-level box describing tracks(s) in an ISOBMFF file. In yet another example, decoder initialization information may be signaled at the communication protocol level, such as in a DASH MPD describing a representation containing tracks. In yet another example, decoder initialization information may be signaled at the communication session level, such as in RTP header extensions, SDP proposals, and / or SDP responses describing data that may be requested as part of a communication session.

[0064] To address the aforementioned and other issues, a methodology summarized below is presented. These items should be considered as examples for explaining general concepts, rather than interpreted in a narrow sense. Furthermore, these items can be applied individually or in combination in any way.

[0065] Example 1

[0066] Certain video decoder initialization information is signaled to the video decoder. In one example, the decoder initialization information includes at least one or more of the following parameters: the maximum number of decoded images stored in the DPB when decoding the bitstream (maxDecPics); the maximum decoded image width of all encoded and decoded images in the bitstream of the luma sample (maxDecPicW); the maximum decoded image height of all encoded and decoded images in the bitstream of the luma sample (maxDecPicH); whether certain codec tools and / or certain NAL units are enabled / used when decoding the bitstream and can be signaled as decoder initialization information; and / or the maximum point of intersection (POC) distance between the current image and its reference image when decoding the bitstream.

[0067] In one example, certain codec tools may be one or more of the following: inter-layer prediction, reference image resampling (RPR) or adaptive resolution, surround motion compensation, motion prediction from a reference image (e.g., temporal motion vector prediction (TMVP) or sub-block-based temporal motion vector prediction (SbTMVP)), color palette, adaptive color transformation (ACT), and / or intra-block copying (IBC). In one example, a NAL unit may be one or more of the following: ALF APS NAL unit, LMCS APS NAL unit, or scaled list APS NAL unit.

[0068] Example 2

[0069] The decoder is initialized based on the video decoder initialization information, when some video decoder initialization information is available for decoding the bitstream. In one example, the decoder is initialized such that the DPB contains at least maxDecPics image slots, one of which is available for each decoded image. In another example, the decoder is initialized such that the width of each image slot in the DPB is at least maxDecPicW luma samples. In yet another example, the decoder is initialized such that the height of each image slot in the DPB is at least maxDecPicH luma samples.

[0070] Example 3

[0071] In one example, video decoder initialization information is signaled in the DCI NAL unit specified in the VVC. Additionally, one or more of the following may be applied: In one example, when all CVSs of the bitstream conform to one profile and one level, the parameters of the decoder initialization information exist only in the DCI NAL unit. In one example, when there is only one profile_tier_level() syntax structure in the DCI NAL unit, the parameters of the decoder initialization information exist only in the DCI NAL unit. In one example, the decoder initialization information includes at least one or more of the following parameters. The maximum number of decoded images stored in the DPB during bitstream decoding (maxDecPics); the maximum decoded image width of all codec images in the bitstream at the luma sample (maxDecPicW); the maximum decoded image height of all codec images in the bitstream at the luma sample (maxDecPicH); the maximum color format of all codec images in the bitstream (e.g., the maximum value of sps_chroma_format_idc); the maximum bit depth of all codec images in the bitstream (e.g., the maximum value of sps_bitdepth_minus8); the maximum codec image buffer (CPB) size of the bitstream, in bits; whether ALF APS NAL units are enabled / used for the bitstream; whether explicit scaling list APS NAL units are enabled / used for the bitstream; whether LMCS APS units are enabled / used for the bitstream. NAL unit; whether temporal motion vector prediction is enabled / used for the bitstream (e.g., yes if the value of sps_temporal_mvp_enabled_flag is equal to 1 for any reference SPS of the bitstream); whether intra-block copying (IBC) is enabled / used for the bitstream; whether palette encoding / decoding mode is enabled / used for the bitstream; whether adaptive color transformation is enabled / used for the bitstream; whether deblocking is enabled / used for the bitstream (e.g., if deblocking_filter_override_enabled_flag and pps_deblocking_filt are both enabled / used). The value of er_disabled_flag is 0 for any reference PPS of the bitstream (if it is 0, then no); minimum CU size information (e.g., indicated by sps_log2_min_luma_coding_block_size_minus2; note that TMVP storage granularity may depend on the minimum CU size); indicates which padding method is enabled / used for motion compensation (note that this is useful in video codec designs that support multiple padding methods for motion compensation); whether sub-picture segmentation is enabled / used for the bitstream; whether strip segmentation is enabled / used for the bitstream; whether slice segmentation is enabled / used for the bitstream.Whether to enable / use surround motion compensation (e.g., indicated by `sps_ref_wraparound_enabled_flag`); whether to enable / use reference image resampling (indicated by `sps_ref_pic_resampling_enabled_flag`); the offset / variation applied to the image size to calculate the scaling (indicated by `pps_sclaing_win_left_offset / pps_sclaing_win_right_offset / pps_sclaing_win_top_offset / pps_sclaing_win_bottom_offset`); and / or whether to enable / use long-term reference images for inter-frame prediction (indicated by `sps_long_term_ref_pics_flag`) can be included in the decoder initialization information.

[0072] Example 4

[0073] In one example, video decoder initialization information is signaled in an SEI message. For example, decoder initialization information can be signaled in a message named Decoder Initialization Information (DII) SEI message. Furthermore, one or more of the following apply: In one example, the DII SEI message can be used with a video bitstream encoded using any video codec, such as VVC, HEVC, AVC, EVC, Audio Video Codec Standard (AVS), AOMedia Video 1 (AV1), AOMedia Video 2 (AV2), Video Codec Format 1 (VC1) (also known as SMPTE 421), or a combination thereof. In one example, the information provided in the DII SEI message applies to the entire bitstream. In one example, when present in the bitstream, the DII SEI message should be present in the first AU of the bitstream, and may also be present in other AUs of the bitstream, such as IRAP AUs. In one example, the DII SEI message can be provided in the bitstream or through an external mechanism. In one example, when all CVSs of the bitstream are indicated to conform to the same level, the DII SEI message can be used only with the video bitstream. In one example, when all CVSs of the bitstream are indicated to conform to the same level, the DII SEI message can be used only with the video bitstream, and for VVC and HEVC, all CVSs of the bitstream are indicated to conform to the same level. In one example, when all CVSs of the bitstream conform to one level, the DII SEI message can be used only with the video bitstream. In one example, when all CVSs of the bitstream conform to one level, the DII SEI message can be used only with the video bitstream, and for VVC and HEVC, all CVSs of the bitstream conform to one level.

[0074] In one example, the DII SEI message includes syntax elements indicating at least one or more of the following parameters: the maximum layer of all CVS conformations in the bitstream; the maximum level of all CVS conformations in the bitstream; the maximum number of decoded pictures stored in the DPB when decoding the bitstream (maxDecPics); the maximum decoded picture width of all codec pictures in the bitstream in the luma sample (maxDecPicW); the maximum decoded picture height of all codec pictures in the bitstream in the luma sample (maxDecPicH); the maximum color format of all codec pictures in the bitstream (e.g., the maximum value of sps_chroma_format_idc in VVC or chroma_format_idc in HEVC or AVC); the maximum bit depth of all codec pictures in the bitstream (e.g., sps_bitdepth_minus8 in VVC). The maximum value of `sps_bitdepth_luma_minus8` or `bit_depth_chroma_minus8` in HEVC or AVC; the maximum luminance bit depth of all encoded and decoded images in the bitstream (e.g., the maximum value of `sps_bitdepth_minus8` in VVC or the maximum value of `bit_depth_luma_minus8` in HEVC or AVC); the maximum chroma bit depth of all encoded and decoded images in the bitstream (e.g., the maximum value of `sps_bitdepth_minus8` in VVC or the maximum value of `bit_depth_chroma_minus8` in HEVC or AVC); the maximum CPB size of the bitstream, in bits; whether ALF is enabled / used for the bitstream. APS NAL unit (ALF APS is not supported for codecs such as HEVC and AVC, is this true?); Whether to enable / use explicit scaling list APS NAL unit for bitstream (ALF APS is not supported for codecs such as HEVC and AVC, is this true?); Whether to enable / use LMCS APS NAL unit for bitstream (ALF APS is not supported for codecs such as HEVC and AVC, is this true?); Whether to enable / use temporal motion vector prediction for bitstream (e.g., for VVC, this is the maximum value of sps_temporal_mvp_enabled_flag); Whether to enable / use intra-block copy (IBC) for bitstream; Whether to use palette codec mode for bitstream (palette codec mode is not supported for codecs such as AVC, is this true?); Whether to enable / use adaptive color transformation for bitstream (adaptive color transformation is not supported for codecs such as AVC, is this true?);Whether deblocking is enabled / used for the bitstream (for codecs such as HEVC and VVC, no if the values ​​of deblocking_filter_override_enabled_flag and pps_deblocking_filter_disabled_flag are equal to 0 for any reference PPS of the bitstream); minimum CU size information (e.g., indicated by sps_log2_min_luma_coding_block_size_minus2, note that TMVP storage granularity may depend on the minimum CU size); indicating which padding method is enabled / used for motion compensation (note that this is important in video codec designs that support multiple padding methods for motion compensation). (Very useful); Whether sub-picture segmentation is enabled / used for the bitstream; Whether strip segmentation is enabled / used for the bitstream; Whether slice segmentation is enabled / used for the bitstream; Whether surround motion compensation is enabled / used (e.g., indicated by `sps_ref_wraparound_enabled_flag`); Whether reference picture resampling is enabled / used (indicated by `sps_ref_pic_resampling_enabled_flag`); Offset / variation applied to picture size to calculate scaling (indicated by `pps_sclaing_win_left_offset / pps_sclaing_win_right_offset / pps_sclaing_win_top_of_fset / pps_sclaing_win_bottom_offset`); and / or Whether long-term reference pictures are enabled / used for inter-frame prediction (indicated by `sps_long_term_ref_pics_flag`) can be included in the DIISEI message.

[0075] Example 5

[0076] In one example, the video DII is signaled in the ISOBMFF file or in a file according to a file format exported from and compatible with ISOBMFF. Additionally, one or more of the following may apply: In one example, different groups of DIIs are signaled in the file-level or movie-level box, and each group of DIIs applies to one or more groups of alternative video tracks in the file. In one example, the DII is signaled in the file-level metadata box. In one example, the DII is signaled in the movie-level metadata box. In one example, the DII is signaled in the movie header box. In one example, the DII is signaled in the file-level or movie box and applied to all video tracks in the file. In one example, the DII is signaled in the file-level metadata box. In one example, the DII is signaled in the movie-level metadata box. In one example, the DII is signaled in the movie header box. In one example, the DII is signaled in the track-level box of a video track or picture sequence track and applied to the entire video track. In one example, the DII is signaled in the sample description box, and when multiple sample entries exist, all sample entries are required to have the same DII. In one example, the DII is signaled in the track header box. In another example, the DII is signaled in the track group box. In yet another example, the DII is signaled in the track group type box, and a grouping type, such as 'sdii', is defined, indicating that the track belongs to a group of tracks sharing the same DII. Tracks with the same track_group_id value in the TrackGroupTypeBox of track_group_type 'sdii' are mapped to share the same DII. In one example, the DII is signaled in the track-level metadata box. In one example, the DII is signaled in the track-level box and applies to the current track and all other tracks that are indicated as the alternative track to the current track. In one example, the DII is signaled in the sample description box, and when multiple sample entries exist, all sample entries are required to have the same DII. Additionally, in one example, the DII is signaled in the track header box. In another example, the DII is signaled in the track-level metadata box.

[0077] In one example, when all CVSs of a bitstream are indicated to use the same video codec, the DII may be signaled only for a file or track, a set of tracks, or a set of alternative tracks. In another example, when all CVSs of a bitstream are indicated to conform to the same grade, the DII may be signaled only for a file or track, a set of tracks, or a set of alternative tracks. In yet another example, when all CVSs of a bitstream are indicated to conform to the same grade, the DII may be signaled only for a file or track, a set of tracks, or a set of alternative tracks, and for VVC and HEVC, all CVSs of all bitstreams are indicated to conform to the same grade. In yet another example, when all CVSs of a bitstream conform to a grade, the DII may be signaled only for a file or track, a set of tracks, or a set of alternative tracks. In yet another example, when all CVSs of a bitstream conform to a grade, the DII may be signaled only for a file or track, a set of tracks, or a set of alternative tracks, and for VVC and HEVC, all CVSs of the bitstream conform to a single grade.

[0078] In one example, the DII includes fields indicating at least one or more of the following parameters: the video codec used to encode the bitstream(s); the level of the bitstream(s); the maximum layer of all CVS conformances of the bitstream(s); the maximum level of all CVS conformances of the bitstream(s); the maximum number of decoded pictures stored in the DPB when decoding the bitstream(s); the maximum decoded picture width of all codec pictures in the bitstream(s) in the luma sample(s); the maximum decoded picture height of all codec pictures in the bitstream(s) in the luma sample(s); the maximum color format of all codec pictures in the bitstream(s) (e.g., the maximum value of sps_chroma_format_idc in VVC or chroma_format_idc in HEVC or AVC); the maximum bit depth of all codec pictures in the bitstream(s) (e.g., the maximum value of chroma_format_idc in VVC or HEVC or AVC); the maximum bit depth of all codec pictures in the bitstream(s) (e.g., the maximum value of sps_chroma_format_idc in VVC or HEVC or AVC). The maximum value of sps_bitdepth_minus8 or the maximum values ​​of bit_depth_luma_minus8 and bit_depth_chroma_minus8 in HEVC or AVC; the maximum luminance bit depth of all codec images in (multiple) bitstreams (e.g., the maximum value of sps_bitdepth_minus8 in VVC or the maximum value of bit_depth_luma_minus8 in HEVC or AVC); the maximum chroma bit depth of all codec images in (multiple) bitstreams (e.g., the maximum value of sps_bitdepth_minus8 in VVC or the maximum value of bit_depth_chroma_minus8 in HEVC or AVC); the maximum CPB size of (multiple) bitstreams in bits; whether ALFAPS is enabled / used for (multiple) bitstreams. NAL unit (for codecs such as HEVC and AVC, ALF APS is not supported, is this true or false); whether explicit scaling list APS is enabled / used for (multiple) bitstreams; NAL unit (for codecs such as HEVC and AVC, ALF APS is not supported, is this true or false); whether LMCS APS is enabled / used for (multiple) bitstreams; NAL unit (for codecs such as HEVC and AVC, ALF APS is not supported, is this true or false); whether temporal motion vector prediction is enabled / used for at least one bitstream (e.g., for VVC, this is the maximum value of sps_temporal_mvp_enabled_flag); whether IBC is enabled / used for at least one bitstream; whether palette codec mode is enabled / used for at least one bitstream (for codecs such as AVC, palette codec mode is not supported, is this true or false);Whether adaptive color transformation is enabled / used for at least one bitstream (for codecs, e.g., for AVC, adaptive color transformation is not supported, this is true); whether deblocking is enabled / used for at least one bitstream (for codecs, e.g., HEVC and VVC, this is true if the values ​​of deblocking_filter_override_enabled_flag and pps_deblocking_filter_disabled_flag are equal to 0 for any reference PPS of the bitstream, this is true); minimum CU size information (e.g., indicated by sps_log2_min_luma_coding_block_size_minus2, note that TMVP storage granularity may depend on the minimum CU size); indication of which padding method is enabled / used for motion compensation of at least one bitstream (note that this is true if the padding method is not supported for motion compensation). The following fields can be included in the DII: whether subpicture segmentation is enabled / used for at least one bitstream; whether strip segmentation is enabled / used for at least one bitstream; whether slice segmentation is enabled / used for at least one bitstream; whether surround motion compensation is enabled / used for at least one bitstream (e.g., indicated by `sps_ref_wraparound_enabled_flag`); whether reference picture resampling is enabled / used for at least one bitstream (indicated by `sps_ref_pic_resampling_enabled_flag`); the offset / variation applied to the picture size to calculate the scaling (indicated by `pps_sclaing_win_left_offset / pps_sclaing_win_right_offset / pps_sclaing_win_top_of_fset / pps_sclaing_win_bottom_offset`); and / or whether long-term reference pictures are enabled / used for inter-frame prediction of at least one bitstream (indicated by `sps_long_term_ref_pics_flag`).

[0079] Example 6

[0080] In one example, the video DII is signaled in the DASH MPD. One or more of the following may apply: In one example, the DII is signaled in the adaptive set and applied to all representations in the adaptive set. In one example, the DII is signaled in the representation and applied to the entire representation. In one example, the DII is optional and can be signaled for the adaptive set or representation only if all CVs of the bitstream are indicated to use the same video codec. In one example, when all CVSs of the bitstream are indicated to conform to the same level, the DII may be signaled for the adaptive set or representation only. In one example, when all CVSs of the bitstream are indicated to conform to the same level, the DII may be signaled for the adaptive set or representation only, and for VVC and HEVC, all CVSs of the bitstream are indicated to conform to the same level. In one example, when there exists a level that all CVSs of the bitstream conform to, the DII may be signaled for the adaptive set or representation only. In one example, when there exists a level that all CVSs of the bitstream conform to, the DII can be directed only to the adaptive set or indicated by signaling. For VVC and HEVC, there exists a level that all CVSs of the bitstream conform to.

[0081] In one example, DII includes fields that indicate at least one or more parameters described in Example 5.

[0082] Example 7

[0083] In one example, video decoder initialization information is signaled in the RTP header extension or as an SDP parameter used in SDP proposals / responses. One or more of the following may apply: In one example, the DII is optional and may be signaled only during session negotiation in the SDP line for a specific video codec (e.g., SDP proposal / response) when the same grade of the video codec will be used for the entire session. In one example, the DII may be signaled only if all CVSs of the bitstream are indicated to conform to the same grade, and for VVC and HEVC, all CVSs of the bitstream are indicated to conform to the same level. In one example, the DII may be signaled only if there exists a grade that all CVSs of the bitstream conform to. In one example, the DII is signaled only if there exists a grade that all CVSs of the bitstream conform to, and for VVC and HEVC, there exists a level that all CVSs of the bitstream conform to. In one example, the DII is optional and can be signaled only in the RTP header extension after session negotiation when all CVSs of the bitstream to be carried in the RTP stream use the same video codec throughout the session. In one example, the DII can be signaled only if all CVSs of the bitstream are indicated to conform to the same level. In one example, the DII can be signaled only if all CVSs of the bitstream are indicated to conform to the same level, and for VVC and HEVC, all CVSs of the bitstream are indicated to conform to the same level. In one example, the DII can be signaled only if there exists a level that all CVSs of the bitstream conform to. In one example, the DII is signaled only if there exists a level that all CVSs of the bitstream conform to, and for VVC and HEVC, all CVSs of the bitstream conform to a single level.

[0084] In one example, DII includes fields that indicate at least one or more parameters described in Example 5.

[0085] Example 8

[0086] The decoder may be reinitialized when the grade / level / layer information changes. In one example, the decoder will be reinitialized if one or more syntax elements of the GCI specified in VVC change.

[0087] Example 9

[0088] The decoder can be reinitialized when one or more syntax elements of the general timing and HRD parameter syntax change.

[0089] Below are some example implementations of the aspects summarized above, some of which can be applied to the standard specifications of the VVC video file format. Added or modified sections are indicated by underline and bold, and deleted sections are indicated by bold italics.

[0090] In one example, the RBSP syntax for decoding capability information is modified as follows:

[0091]

[0092] In one example, the syntax for adding decoding capability information is as follows:

[0093]

[0094]

[0095] In one example, the semantic modification of the decoding capability information RBSP is as follows:

[0096] The DCI RBSP can be provided to the decoder either by being present in the bitstream, at least contained in the first AU of the bitstream, or externally. Note 1 – The information contained in the DCI RBSP is not required for the operation of the decoding process specified in Clauses 2 to 9 of this specification. If present, all DCI NAL units in the bitstream should have the same content. `dci_reserved_zero_4bits` should be equal to 0 in a bitstream conforming to this version of this specification. Values ​​greater than 0 in `dci_reserved_zero_4bits` are reserved for future use by ITU-T|ISO / IEC. The decoder should allow values ​​greater than 0 in `dci_reserved_zero_4bits` to appear in the bitstream and should ignore the value of `dci_reserved_zero_4bits`. `dci_num_ptls_minus1` plus 1 specifies the number of `profile_tier_level()` syntax structures in the DCI NAL unit. The value of `dci_num_ptls_minus1` should be in the range of 0 to 14 (inclusive). The value 15 of dci_num_ptls_minus1 is reserved for future use by ITU-T|ISO / IEC. Bitstream conformance requires that each OLS in the CVS of the bitstream conforms to at least one of the profile_tier_level() syntax structures in the DCI NAL unit. Note 2 – The DCI NAL unit may include PTL information, possibly carried in multiple profile_tier_level() syntax structures, applied to multiple OLS, and does not need to include PTL information for each OLS separately.

[0097] dci_extension_flag equal to 0 indicates that there is no dci_extension_flag. It exists in the DCI RBSP syntax structure. `dci_extension_flag` equal to 1 specifies... It exists in the DCIRBSP syntax structure.

[0098] `dci_extension_alignment_bit_equal_to_one` should be equal to 1. Alternatively, replace the following two lines of syntax with a 7-bit field, for example, named `dci_extension_alignment_zero_7bits`, and require that the value of this field be equal to 0:

[0099]

[0100]

[0101] The `dci_extension_data_flag` flag can have any value. Its presence and value do not affect the decoding process specified in this version of the specification. Decoders conforming to this version of the specification should ignore all `dci_extension_data_flag` syntax elements.

[0102] In one example, the extended semantics of decoding capability information are added / modified as follows:

[0103]

[0104] This embodiment can be applied to VSEI. Most of the relevant parts that have been added or modified are highlighted in bold underline, and some deleted parts are highlighted in bold italics.

[0105]

[0106] Below are some example implementations of aspects summarized above, some of which can be applied to VSEI. Added or modified sections are indicated by underline and bold, and deleted sections are indicated by bold italics.

[0107] In one example, the general category of SEI messages is modified as follows:

[0108] Clause 8 specifies the syntax and semantics of SEI messages. For SEI messages with an empty specified syntax structure, such as subordinate random access point SEI messages, simply indicating the existence of an SEI message (e.g., indicated by a payload type indicator) is sufficient to convey relevant information (e.g., by indicating that a set of specified constraints is satisfied). The semantics and persistence scope of each SEI message are specified in the semantic specification of each particular SEI message. Note – The persistence information for SEI messages is summarized below.

[0109] The persistence scope (informativeness) of SEI messages

[0110]

[0111] The persistence scope (informativeness) of SEI messages

[0112] SEI news Durability range Sphere rotation Specify by the syntax of the SEI message Region-by-region packaging Specify by the syntax of the SEI message Omnidirectional viewport Specify by the syntax of the SEI message Frame field information PU containing SEI messages Sampling aspect ratio information Specify by the syntax of the SEI message Decoder initialization information Bit stream containing access units associated with SEI messages ...

[0114] In one example, the decoder initialization information SEI message syntax is added / modified as follows:

[0115]

[0116] In one example, the semantics of the decoder initialization information SEI message are added / modified as follows:

[0117]

[0118]

[0119] Figure 1 This is a protocol diagram of an example mechanism 100 used to establish a communication session with SDP. For example, a communication session can be established for transmitting video data between an encoder and / or content server and a decoder. For example, a communication session can be established for streaming video from a sender to a receiver for display to a user (e.g., television). In another example, the sender and receiver can be peers transmitting video in a bidirectional direction (e.g., video call). As a specific example, the sender can send a live video data stream to the receiver, and the receiver can return a live video data stream to the sender.

[0120] In SDP, the device initiating the communication is called the proposer (e.g., a decoder), and the responding device is called the responder (e.g., an encoder). In step 102, the proposer can initiate a video communication session by sending an SDP proposal to the responder. An SDP proposal is a message describing the proposer's media capabilities, thus describing the media the proposer is willing to receive. The responder reviews the SDP proposal and determines whether the responder can meet the conditions in the SDP proposal. The responder can accept or reject the SDP proposal from step 102. Assuming the responder decides to accept the request, the responder can indicate this acceptance by sending an SDP response to the proposer in step 104. The SDP response describes the media the responder is willing to send based on the SDP proposal. For example, when the responder agrees to the proposer's terms, the SDP response may include the same media description as the SDP proposal. In another example, when the responder agrees to some, but not all, of the proposer's terms, the SDP response may include a subset of the media capabilities described in the SDP proposal. Assuming some agreement is reached, the responder can then transmit media to the proposer in step 106 based on the description in the SDP response from step 104. In a bidirectional context, mechanism 100 can be executed twice, with each device acting as a proposer for the media stream to be received.

[0121] As described above, this disclosure signals decoder initialization information to the decoder, which may be the proposer in mechanism 100. This allows the decoder to perform an initialization process based on parameters of multiple potential media streams, minimizing the need for decoder re-initialization when exchanges occur between streams. In one example, decoder initialization information may be signaled / requested by the proposer in an SDP proposal at step 102. The encoder can then respond by signaling decoder initialization information in an SDP response at step 104. Then, at step 104, the decoder can perform initialization based on the decoder initialization information received in the SDP response. In a specific example, decoder initialization information may be requested and / or sent in an SDP proposal and / or in an SDP response within an RTP header extension.

[0122] Figure 2 This is a protocol diagram of example mechanism 200 for performing video streaming according to DASH. DASH allows the receiver (e.g., proposer / decoder) to select from multiple alternative media streams during a single media session. In this way, the receiver can dynamically increase or decrease the video resolution based on changing network conditions. Therefore, the receiver continuously receives the best available video resolution based on current network conditions, while avoiding pausing the video stream to wait for more data when network conditions deteriorate. DASH can be used in conjunction with SDP. For example, mechanism 200 can be used to transmit media according to step 106 of mechanism 100.

[0123] The above functionality is achieved by sending the MPD from the sender to the receiver in step 202. The MPD describes multiple alternative and interchangeable media streams. For example, each media stream may describe the same media at different resolutions, compressions, etc. In step 204, the receiver uses the description in the MPD to request a segment of the media. For example, the receiver may check the current network conditions and / or the current buffer conditions. When the buffer fills with new media data faster than the display speed of old media data, the receiver may request a segment from a higher-resolution media stream. When the buffer becomes empty because the display of media data occurs faster than the rate at which new media data can be received, the receiver may request a segment from a lower-resolution media stream. In step 206, the sender (e.g., a transponder, encoder, and / or content server) may send the segment requested in step 204. Steps 204 and 206 are repeated until media rendering is complete (or the user cancels the session).

[0124] As described above, this disclosure signals decoder initialization information to the decoder, which may be the receiver in mechanism 200. This allows the decoder to perform an initialization process based on parameters of multiple potential media streams, minimizing the need for decoder re-initialization when streams are exchanged. In an example, the decoder initialization information may be signaled in the MPD notified in step 202. For example, the decoder initialization information may describe each media stream that the receiver can request. The decoder can then perform initialization based on the decoder initialization information in the MPD.

[0125] Figure 3This is a schematic diagram illustrating the description of video by MPD 300 used in DASH, for example, in step 202 of mechanism 200. MPD 300 describes the media stream according to period 310, adaptive sets 320, representations 330, and segments 340. Period 310 includes timing data and indicates a content period during which a consistent set of codec versions of the media content is available (e.g., a set of available bitrates, languages, subtitles, subtitles, etc., remains unchanged). Period 310 may contain one or more adaptive sets 320. Adaptive sets 320 include a set of interchangeable encoded versions of one or more media content components. For example, a first adaptive set 320 may include a primary video component, a second adaptive set 320 may include a primary audio component, a third adaptive set 320 may include subtitles, etc. Adaptive sets 320 may also include multiplexed content, such as combining video and audio. Each adaptive set 320 includes one or more representations 330. Representations 330 describe a deliverable encoded version of one or more media content components, such as an ISOBMFF version of the media content. The media content in 330 is further divided into segments 340. Segment 340 is a predefined byte size (e.g., 1,000 bytes) and / or playback interval (e.g., 2 or 5 seconds) of the media content. Each segment 340 is an individually addressable unit of data that can be downloaded using a universal resource locator (URL) advertised via MPD 300.

[0126] For example, for each cycle 310, the decoder can select one or more adaptive sets 320 to obtain video, audio, and / or closed captions based on the data in the MPD 300. The decoder can then begin streaming media data from the selected adaptive sets 320. The decoder can select a representation 330 for each adaptive set 320 based on current network conditions and use a URL to obtain the corresponding segment 340 to be presented to the user. As network conditions change, the decoder can select a different representation 330 within the corresponding adaptive set 320. This allows the decoder to obtain the corresponding media segment 340 at the best possible quality for presentation without pausing to refill the buffer based on current network conditions.

[0127] In the example, decoder initialization information can be included in the data describing the adaptation set 320 and / or the data describing the representation 330 in the MPD 300. For example, the adaptation set 320 may include decoder initialization information for each representation 330 contained within the adaptation set 320. In another example, each representation 330 may include decoder initialization information describing the media of that representation 330. The decoder can then use the decoder initialization information to perform an initialization process. In this way, the decoder is initialized for any representation 330 that the decoder may select. Therefore, the decoder does not need to be reinitialized due to swapping representations 330 within the selected adaptation set 320.

[0128] Figure 4 This is a schematic diagram of a media file 400 stored in an ISOBMFF. For example, media file 400 may be stored in an ISOBMFF and used as a DASH representation. The ISOBMFF media file 400 is stored in multiple frames that carry objects and / or data associated with media content or media presentation. For example, media file 400 may include a file type frame (e.g., ftyp) 430, a movie frame (e.g., moov) 410, and a media data frame (e.g., mdat) 420.

[0129] File type box 430 can carry data describing the entire file, and therefore can carry file-level data. Thus, a file-level box is any box containing data related to the entire media file 400. For example, file type box 430 can include a file type indicating the version number and / or compatibility information of the ISO specification for the media file 400. Movie box 410 can carry data describing the movie contained in the media file, and therefore can carry movie-level data. A movie-level box is any box containing data describing the entire movie contained in the media file 400. Movie box 410 can contain a wide range of sub-boxes for containing data for various purposes. For example, movie box 410 contains track boxes 411, which carry metadata describing the tracks presented in the media. For example, one track box 411 can carry an audio description of the audio data in media data box 420, another track box 411 can carry a video description of the video data in media data box 420, and yet another track box 411 can carry prompts for streaming and / or playback of the media data in media data box 420. It should be noted that a track can be referred to as a timing sequence of related samples. For example, a media track may include a sequence of images or sampled audio, while a metadata track may include a sequence of metadata in units of metadata. The data describing a track is track-level data, therefore any box describing a track is a track-level box.

[0130] Media data frame 420 includes interleaved and time-ordered media data for media presentation (e.g., codec video pictures and / or audio in one or more media tracks). For example, media data frame 420 may include bitstreams of video data encoded according to VVC, AVC, HEVC, etc. Media data frame 420 may include video pictures, audio, text, or other media data for display to the user.

[0131] As described above, this disclosure signals decoder initialization information to the decoder. This allows the decoder to perform an initialization process based on parameters of multiple potential media streams, minimizing the need for decoder re-initialization when exchanging between streams. In the example, decoder initialization information may be signaled in media file 400. For example, decoder initialization information may be signaled in file-level boxes, movie-level boxes, and / or track-level boxes, such as file type box 430, movie box 410, and / or track box 411. As described above, ISOBMFF includes many different boxes for specific purposes. In various examples, decoder initialization information may be signaled in file-level metadata boxes (included in file type box 430), movie-level metadata boxes (included in movie box 410), movie header box (mvhd) (included in movie box 410), sample description box (stsd) (included in track box 411), track header box (included in track box 411), track group box (included in track box 411), track-level metadata box (included in track box 411), other boxes, and / or various combinations thereof.

[0132] Figure 5This is a schematic diagram of a bitstream 500 containing encoded and decoded visual media data. Bitstream 500 contains media data that has been encoded / compressed by an encoder for decoding / decompression by a decoder. For example, bitstream 500 can be included in a media data frame 420 of an ISOBMFF media file 400. Furthermore, bitstream 500 can be included in a representation 330 in DASH. Bitstream 500 can be encoded and decoded according to various codec formats, such as VVC, AVC, EVC, HEVC, etc. In some codec formats, bitstream 500 is represented as a series of NAL units 510. NAL units 510 are data units sized to fit within a data packet. For example, VVC contains many types of NAL units 510. Bitstream 500 can contain Video Codec Layer (VCL) NAL units containing video data and non-VCL NAL units containing data describing the VCL NAL units, the codec tools used, and codec constraints. In the example, bitstream 500 may include DCI NAL unit 511 and / or SEI NAL unit 515. DCI NAL unit 511 is a non-VCL NAL unit that contains data describing the encoding / decoding capabilities required by the decoder to decode the corresponding bitstream. SEI NAL unit 515 contains data that assists in processes related to decoding, display, or other purposes, but is not required by the decoding process to determine sample values ​​in the decoded image. In the example, decoder initialization information may be included in DCI NAL unit 511 and / or SEI NAL unit 515. As a specific example, SEI NAL unit 515 may contain DII SEI message 516, which is a SEI message specifically designed to carry decoder initialization information for bitstream 500. As a specific example, bitstream 500 may be further divided into AUs, and DII SEI message 516 may be included in the first AU of bitstream 500. Therefore, the decoder can obtain the first AU of each bitstream 500, decode it, and display it as part of the media presentation. Then, the decoder can perform initialization based on the decoder initialization information in each relevant bitstream 500 to avoid re-initialization.

[0133] Figure 6 This is a block diagram of an example video processing system 600 that can implement the various techniques disclosed herein. Various implementations may include some or all of the components in system 600. System 600 may include an input 602 for receiving video content. The video content may be received in a raw or uncompressed format (e.g., 8 or 10-bit multi-component pixel values), or in a compressed or encoded format. Input 602 may represent a network interface, a peripheral bus interface, or a storage interface. Examples of network interfaces include wired interfaces (such as Ethernet, Passive Optical Networking (PON), etc.) and wireless interfaces (such as Wi-Fi or cellular interfaces).

[0134] System 600 may include an encoding / decoding component 604 capable of implementing the various encoding / decoding or coding methods described herein. Encoding / decoding component 604 can reduce the average bit rate of the video from input 602 to output to produce an encoded / decoded representation of the video. Therefore, encoding / decoding techniques are sometimes referred to as video compression or video transcoding techniques. The output of encoding / decoding component 604 may be stored or transmitted via connected communication, as represented by component 606. The stored or communicated bitstream (or encoded / decoded) representation of the video received at input 602 may be used by component 608 to generate pixel values ​​or displayable video that is sent to display interface 610. The process of generating user-visible video from the bitstream representation is sometimes referred to as video decompression. Furthermore, although some video processing operations are referred to as “encoding / decoding” operations or tools, it should be understood that the encoding / decoding tool or operation is used at the encoder, and the corresponding decoding tool or operation will be inverted by the decoder to retrieve the result of the encoding / decoding.

[0135] Examples of peripheral bus interfaces or display interfaces may include Universal Serial Bus (USB), High Definition Multimedia Interface (HDMI), or DisplayPort. Examples of storage interfaces include SATA (Serial Advanced Technology Accessory), PCI, IDE, etc. The technologies described herein can be implemented in a variety of electronic devices, such as mobile phones, laptops, smartphones, or other devices capable of digital data processing and / or video display.

[0136] Figure 7 This is a block diagram of an example video processing apparatus 700. Apparatus 700 can be used to implement one or more of the methods described herein. Apparatus 700 can be implemented in smartphones, tablets, computers, Internet of Things (IoT) receivers, etc. Apparatus 700 may include one or more processors 702, one or more memories 704, and video processing hardware 706. The processors(multiple) 702 may be configured to implement one or more methods described herein. The memories(multiple) 704 may be used to store data and code used to implement the methods and techniques described herein. The video processing hardware 706 may be used to implement some of the techniques described herein in hardware circuitry. In some embodiments, the video processing hardware 706 may be at least partially included in the processor 702, such as a graphics coprocessor.

[0137] Figure 8This is a flowchart of an example method 800 for video processing. Method 800 includes signaling in step 802 to notify video decoder initialization information containing a series of initialization parameters. In the context of an encoder, the signaling notification includes obtaining the video decoder initialization information and encoding these parameters for transmission to the decoder. In the context of a decoder, the signaling notification includes receiving the video decoder initialization information and initializing the decoder to prepare for decoding a visual media data file. In step 804, a conversion is performed between visual media data and a file storing information corresponding to the visual media data according to a video file format. In the context of an encoder, this conversion can be performed by receiving visual media data, encoding the visual media data into a visual media data file of a video file format based on the video decoder initialization information, and storing the video media data file for transmission to the decoder. In the context of a decoder, this conversion can be performed by decoding the visual media data file of the video file format to obtain visual media data for display using settings selected based on the video decoder initialization information.

[0138] As described above, video decoder initialization information can be signaled through various mechanisms, depending on the example. For example, decoder initialization information can be signaled in at least one DCI NAL unit in at least one bitstream. In another example, decoder initialization information can be signaled in at least one DII SEI message in at least one bitstream. In a particular example, the DII SEI message may be required to be present in the first AU of the corresponding bitstream. In another example, decoder initialization information can be signaled in an ISOBMFF file at the file level, movie level, at least one track level, or a combination thereof. For example, decoder initialization information can be signaled in a file level metadata frame, movie level metadata frame, movie header frame, sample description frame, track header frame, track group frame, track level metadata frame, or a combination thereof. In another example, decoder initialization information can be signaled in a DASH MPD. For example, decoder initialization information can be signaled in an adaptive set, representation, or a combination thereof. In another example, decoder initialization information can be signaled in an RTP header extension. For example, decoder initialization information can be signaled as part of an SDP proposal, SDP response, or a combination thereof.

[0139] Video decoder initialization information may include a series of initialization parameters. For example, video decoder initialization information may include the same parameters that are set to different values ​​for different bitstreams, tracks, and / or representations. Furthermore, video decoder initialization information may include multiple different parameters for various bitstreams, tracks, and / or representations. Then, when switching between indicated bitstreams, tracks, and / or representations, the decoder can initialize itself using any or all of the series of initialization parameters to minimize the re-initialization settings. For example, video decoder initialization information includes maxDecPics stored in the DPB when decoding the bitstream, the maximum maxDecPicW of the encoded / decoded images in the bitstream, the maxDecPicH of the encoded / decoded images in the bitstream, or combinations thereof. Furthermore, video decoder initialization information may include indications of the use of inter-layer prediction, reference image resampling, surround motion compensation, motion vector prediction from the reference image, palette encoding / decoding mode, adaptive color transformation, intra-block copying, ALF APS NAL units, LMCS APS NAL units, scaling list APS NAL units, or combinations thereof in the corresponding bitstream. Additionally, video decoder initialization information may include an indication of the maximum image sequence count between the current image and the corresponding reference image. In addition, the video decoder initialization information may include indications of the maximum color format, maximum bit depth, maximum codec picture buffer size, minimum CU size, scaling ratio calculation information, or combinations thereof. Furthermore, the video decoder initialization information may include indications of the use of deblocking, padding, sub-picture segmentation, strip segmentation, slice segmentation, surround motion compensation, reference picture resampling, long-term reference images, or combinations thereof. Furthermore, the video decoder initialization information may include the maximum layer, the maximum level, or combinations thereof, of all CVS conformances for the corresponding bitstream. Furthermore, the video decoder initialization information may include indications of the video codec used to perform conversions between visual media data and visual media data files. Finally, the video decoder initialization information may include the level conformances for all bitstreams.

[0140] In one example, when executed by the decoder, the decoder can be reinitialized when the PTL information changes (e.g., between bitstreams, tracks, and / or representations). In another example, the decoder can be reinitialized when at least one of the general timing parameters and the HRD parameters changes.

[0141] It should be noted that method 800 can be implemented in an apparatus for processing video data, including a processor and a non-transitory memory thereon with instructions, such as a video encoder 1000, a video decoder 1100, and / or an encoder 1200. In this case, the instructions executed by the processor cause the processor to perform method 800. Alternatively, method 800 can be executed by a non-transitory computer-readable medium comprising a computer program product for use by a video encoding / decoding device. This computer program product includes computer-executable instructions stored on the non-transitory computer-readable medium, such that when executed by a processor, it causes the video encoding / decoding device to perform method 800.

[0142] Figure 9 This is a block diagram illustrating an example video codec system 900 that can utilize the techniques disclosed herein. Figure 9 As shown, the video encoding / decoding system 900 may include a source device 910 and a target device 920. The source device 910 generates encoded video data and may be referred to as a video encoding device. The target device 920 can decode the encoded video data generated by the source device 910 and may be referred to as a video decoding device.

[0143] Source device 910 may include video source 912, video encoder 914, and input / output (I / O) interface 916. Video source 912 may include a source such as a video capture device, an interface for receiving video data from a video content provider, and / or a computer graphics system that generates video data, or a combination of these sources. Video data may include one or more pictures. Video encoder 914 encodes the video data from video source 912 to generate a bitstream. The bitstream may include a sequence of bits forming a codec representation of the video data. The bitstream may include codec pictures and associated data. A codec picture is a codec representation of a picture. Associated data may include sequence parameter sets, picture parameter sets, and other syntax elements. I / O interface 916 includes a modulator / demodulator (modem) and / or a transmitter. Encoded video data may be transmitted directly to target device 920 via network 930 through I / O interface 916. Encoded video data may also be stored on storage medium / server 940 for access by target device 920.

[0144] Target device 920 may include I / O interface 926, video decoder 924, and display device 922. I / O interface 926 may include a receiver and / or a modem. I / O interface 926 may acquire encoded video data from source device 910 or storage medium / server 940. Video decoder 924 may decode the encoded video data. Display device 922 may display the decoded video data to a user. Display device 922 may be integrated with target device 920 or may be external to target device 920 configured to connect to an external display device.

[0145] The video encoder 914 and the video decoder 924 can operate according to video compression standards such as High Efficiency Video Codec (HEVC), Multi-Functional Video Codec (VVC), and other current and / or other standards.

[0146] Figure 10 This is a block diagram illustrating an example of a video encoder 1000, which can be... Figure 9 The system 900 shown contains a video encoder 914. The video encoder 1000 can be configured to perform any or all of the techniques disclosed herein. Figure 10 In the example, the video encoder 1000 includes multiple functional components. The techniques described in this disclosure can be shared among the various components of the video encoder 1000. In some examples, the processor can be configured to perform any or all of the techniques described in this disclosure.

[0147] The functional components of the video encoder 1000 may include a segmentation unit 1001, a prediction unit 1002 (which may include a mode selection unit 1003, a motion estimation unit 1004, a motion compensation unit 1005, and an intra-frame prediction unit 1006), a residual generation unit 1007, a transform processing unit 1008, a quantization unit 1009, an inverse quantization unit 1010, an inverse transform unit 1011, a reconstruction unit 1012, a buffer 1013, and an entropy coding unit 1014.

[0148] In other examples, the video encoder 1000 may include more, fewer, or different functional components. In one example, the prediction unit 1002 may include an intra-block copy (IBC) unit. The IBC unit may perform prediction in IBC mode, where at least one reference picture is the picture in which the current video block is located.

[0149] Furthermore, some components, such as the motion estimation unit 1004 and the motion compensation unit 1005, can be highly integrated, but for interpretive purposes... Figure 10 The examples are shown separately.

[0150] The segmentation unit 1001 can segment an image into one or more video blocks. The video encoder 1000 and the video decoder 1100 can support various video block sizes.

[0151] The mode selection unit 1003 can, for example, select one of the intra-frame or inter-frame codec modes based on the error result, and provide the obtained intra-frame or inter-frame codec block to the residual generation unit 1007 to generate residual block data and to the reconstruction unit 1012 to reconstruct the codec block for use as a reference image. In some examples, the mode selection unit 1003 can select a combined intra-frame and inter-frame prediction (CIIP) mode, where the prediction is based on the inter-frame prediction signal and the intra-frame prediction signal. The mode selection unit 1003 can also select the resolution of the motion vector (e.g., sub-pixel or integer pixel precision) for the block in the inter-frame prediction case.

[0152] To perform inter-frame prediction for the current video block, motion estimation unit 1004 can generate motion information for the current video block by comparing one or more reference frames from buffer 1013 with the current video block. Motion compensation unit 1005 can determine the predicted video block for the current video block based on the motion information of the image from buffer 1013 (rather than the image associated with the current video block) and decoded samples.

[0153] The motion estimation unit 1004 and the motion compensation unit 1005 can perform different operations on the current video block. For example, the different operations performed depend on whether the current video block is in an I-strip, a P-strip, or a B-strip.

[0154] In some examples, motion estimation unit 1004 can perform unidirectional prediction of the current video block, and can search for a reference video block for the current video block in the reference images of list 0 or list 1. Then, motion estimation unit 1004 can generate a reference index indicating that the reference image in list 0 or list 1 contains the reference video block, and a motion vector indicating the spatial displacement between the current video block and the reference video block. Motion estimation unit 1004 can output the reference index, prediction direction indicator, and motion vector as motion information for the current video block. Motion compensation unit 1005 can generate a predicted video block for the current block based on the reference video block indicated by the motion information of the current video block.

[0155] In other examples, motion estimation unit 1004 can perform bidirectional prediction of the current video block. Motion estimation unit 1004 can search for a reference video block for the current video block in the reference images of list 0 and can also search for another reference video block for the current video block in the reference images of list 1. Motion estimation unit 1004 can then generate a reference index indicating that the reference images in list 0 or list 1 contain the reference video block, and a motion vector indicating the spatial displacement between the reference video block and the current video block. Motion estimation unit 1004 can output the reference index and the motion vector of the current video block as the motion information of the current video block. Motion compensation unit 1005 can generate a predicted video block for the current video block based on the reference video block indicated by the motion information of the current video block.

[0156] In some examples, the motion estimation unit 1004 may output the complete set of motion information for decoding processing by the decoder. In some examples, the motion estimation unit 1004 may not output the complete set of motion information for the current video. Instead, the motion estimation unit 1004 may refer to the motion information of another video block to signal the motion information of the current video block. For example, the motion estimation unit 1004 may determine that the motion information of the current video block is sufficiently similar to the motion information of adjacent video blocks.

[0157] In one example, the motion estimation unit 1004 may indicate in the syntax structure associated with the current video block that the current video block has the same motion information value as another video block.

[0158] In another example, motion estimation unit 1004 may identify another video block and motion vector difference (MVD) in the syntax structure associated with the current video block. The motion vector difference indicates the difference between the motion vector of the current video block and the motion vector of the indicating video block. Video decoder 1100 may use the motion vector of the indicating video block and the motion vector difference to determine the motion vector of the current video block.

[0159] As discussed above, the video encoder 1000 can predictively signal motion vectors. Two examples of predictive signaling notification techniques that can be implemented by the video encoder 1000 include Advanced Motion Vector Prediction (AMVP) and merge pattern signaling notification.

[0160] The intra-prediction unit 1006 can perform intra-prediction on the current video block. When the intra-prediction unit 1006 performs intra-prediction on the current video block, it can generate prediction data for the current video block based on the decoded samples of other video blocks in the same image. The prediction data for the current video block may include the predicted video block and various syntax elements.

[0161] The residual generation unit 1007 can generate residual data for the current video block by subtracting (or more) predicted video blocks from the current video block. The residual data for the current video block can include residual video blocks corresponding to different sample components in the current video block.

[0162] In other examples, such as in skip mode, residual data for the current video block may not exist, and the residual generation unit 1007 may not perform a subtraction operation.

[0163] The transform processing unit 1008 can generate one or more transform coefficient video blocks of the current video block by applying one or more transforms to the residual video block associated with the current video block.

[0164] After the transform processing unit 1008 generates a transform coefficient video block associated with the current video block, the quantization unit 1009 can quantize the transform coefficient video block associated with the current video block based on one or more quantization parameter (QP) values ​​associated with the current video block.

[0165] The inverse quantization unit 1010 and the inverse transform unit 1011 can apply inverse quantization and inverse transform to the transform coefficient video block respectively to reconstruct the residual video block from the transform coefficient video block. The reconstruction unit 1012 can add the reconstructed residual video block to the corresponding sample points of one or more predicted video blocks generated by the prediction unit 1002 to produce a reconstructed video block associated with the current block for storage in the buffer 1013.

[0166] After the video block is reconstructed by reconstruction unit 1012, a loop filtering operation can be performed to reduce video block artifacts in the video block.

[0167] The entropy encoding unit 1014 can receive data from other functional components of the video encoder 1000. When the entropy encoding unit 1014 receives data, it can perform one or more entropy encoding operations to generate entropy-coded data and output a bitstream including the entropy-coded data.

[0168] Figure 11 This is a block diagram illustrating an example of a video decoder 1100, which can be... Figure 9 The video decoder 924 in the system 900 shown in the figure.

[0169] The video decoder 1100 can be configured to perform any or all of the techniques disclosed herein. Figure 11 In the example, video decoder 1100 includes multiple functional components. The techniques described in this disclosure can be shared among the various components of video decoder 1100. In some examples, the processor can be configured to perform any or all of the techniques described in this disclosure.

[0170] exist Figure 11 In the example, the video decoder 1100 includes an entropy decoding unit 1101, a motion compensation unit 1102, an intra-frame prediction unit 1109, an inverse quantization unit 1104, an inverse transform unit 1105, a reconstruction unit 1106, and a buffer 1107. In some examples, the video decoder 1100 can perform operations related to the video encoder 1000 (…). Figure 10 The decoding process is the overall inversion of the encoding process described.

[0171] Entropy decoding unit 1101 can retrieve the encoded bitstream. The encoded bitstream may include entropy-encoded video data (e.g., encoded blocks of video data). Entropy decoding unit 1101 can decode the entropy-encoded video, and based on the entropy-encoded video data, motion compensation unit 1102 can determine motion information including motion vectors, motion vector precision, reference image list index, and other motion information. Motion compensation unit 1102 can determine such information, for example, by performing AMVP and merge modes.

[0172] The motion compensation unit 1102 can generate motion compensation blocks, possibly based on interpolation filters. The identifier of the interpolation filter to be used at sub-pixel precision can be included in the syntax elements.

[0173] The motion compensation unit 1102 can use the interpolation filter used by the video encoder 1000 during the encoding of a video block to calculate the interpolation values ​​of a sub-integer number of pixels of the reference block. The motion compensation unit 1102 can determine the interpolation filter used by the video encoder 1000 based on the received syntax information and use the interpolation filter to generate a prediction block.

[0174] The motion compensation unit 1102 can use some syntactic information to determine: the size of the blocks used to encode (multiple) frames and / or (multiple) stripes of the encoded video sequence, segmentation information describing how each macroblock of the image of the encoded video sequence is segmented, a mode indicating how each segment is encoded, one or more reference frames (and a list of reference frames) for each inter-frame coded block, and other information for decoding the encoded video sequence.

[0175] Intra-prediction unit 1103 can use, for example, an intra-prediction mode received in the bitstream to form prediction blocks from spatially adjacent blocks. Inverse quantization unit 1104 inverse quantizes (i.e., dequantizes) the quantized video block coefficients provided in the bitstream and decoded by entropy decoding unit 1101. Inverse transform unit 1105 applies the inverse transform.

[0176] The reconstruction unit 1106 can sum the residual blocks using the corresponding prediction blocks generated by the motion compensation unit 1102 or the intra-frame prediction unit 1103 to form a decoded block. As desired, a deblocking filter can also be applied to filter the decoded block to remove block artifacts. The decoded video block is then stored in a buffer 1107, which provides a reference block for subsequent motion compensation / intra-frame prediction and also produces the decoded video for presentation on the display device.

[0177] Figure 12 This is a schematic diagram of an example encoder 1200. Encoder 1200 is suitable for implementing VVC technology. Encoder 1200 includes three loop filters: a deblocking filter (DF) 1202, a sample adaptive offset (SAO) 1204, and an adaptive loop filter (ALF) 1206. Unlike DF 1202, which uses predefined filters, SAO 1204 and ALF 1206 utilize the original samples of the current image and reduce the mean square error between the original and reconstructed samples by adding an offset and applying a finite impulse response (FIR) filter, respectively, using auxiliary information signaling from the encoder / decoder to inform the offset and filter coefficients. ALF 1206 is located in the final processing stage of each image and can be considered as a tool for attempting to capture and repair artifacts generated by previous stages.

[0178] The encoder 1200 also includes an intra-frame prediction component 1208 and a motion estimation / compensation (ME / MC) component 1210, configured to receive input video. The intra-frame prediction component 1208 is configured to perform intra-frame prediction, while the ME / MC component 1210 is configured to perform inter-frame prediction using a reference picture obtained from a reference picture buffer 1212. Residual blocks from inter-frame or intra-frame prediction are fed into a transform (T) component 1214 and a quantization (Q) component 1216 to generate quantized residual transform coefficients, which are then fed into an entropy codec component 1218. The entropy codec component 1218 entropy codes and decodes the prediction results and quantized transform coefficients and sends them to a video decoder (not shown). The quantization component output from the quantization component 1216 can be fed into an inverse quantization (IQ) component 1220, an inverse transform (IT) component 1222, and a reconstruction (REC) component 1224. REC component 1224 can output images to DF 1202, SAO 1204 and ALF 1206 for filtering before these images are stored in reference image buffer 1212.

[0179] The following provides a list of preferred solutions for some embodiments.

[0180] The following solutions illustrate examples of the techniques discussed in this article.

[0181] 1. A method for processing visual media (e.g., Figure 8 The method described in the image (800) includes performing a conversion between a video and a video codec bitstream; wherein the codec bitstream conforms to a format rule, wherein the format rule specifies that the codec bitstream includes decoder initialization information, wherein the decoder initialization information can be used by the decoder to initialize decoder resources for the conversion.

[0182] 2. The method according to Solution 1, wherein the decoder initialization information includes the number of decoded images to be stored in the decoded image buffer during decoding.

[0183] 3. The method according to any one of solutions 1-2, wherein the decoder initialization information includes the maximum image width in the encoding / decoding bitstream.

[0184] 4. The method according to any one of solutions 1-3, wherein the decoder initialization information includes the maximum image height in the encoding / decoding bitstream.

[0185] 5. The method according to any one of solutions 1-4, wherein the decoder initialization packet encoding / decoding tool is enabled.

[0186] 6. The method of any one of the above or below solutions, wherein the decoder is initialized such that the decoded image buffer is controlled to include multiple image slots, wherein the number of image slots is defined by a predefined maximum limit.

[0187] 7. The method of any one of the above or below solutions, wherein the decoder is initialized based on the maximum height or maximum width of the encoded / decoded image in the bitstream.

[0188] 8. The method according to any of the above solutions, wherein decoder initialization information is included in the Decoding Capability Information (DCI) Network Abstraction Layer Unit (NAL) field according to the format rules.

[0189] 9. The method described in any of the above solutions, wherein decoder initialization information is included in the Supplemental Enhancement Information (SEI) message according to the format rules.

[0190] 10. The method described in any of the above solutions, wherein the encoded bitstream is formatted according to the International Organization for Standardization Basic Media File Format (ISOBMFF) and includes decoder initialization information.

[0191] 11. The method described in any of the above solutions, wherein the codec bitstream is formatted according to the Moving Picture Experts Group (MPEG) Dynamic Adaptive Streaming (DASH) Media Presentation Description (MPD) format based on Hypertext Transfer Protocol (MPEG) to include decoder initialization information.

[0192] 12. The method described in any of the above solutions, wherein the encoded / decoded bitstream is formatted according to the Real-Time Transport Protocol (RTP) format to include decoder initialization information.

[0193] 13. The method of solution 12, wherein decoder initialization information is included as a session description protocol parameter.

[0194] 14. The method described in any of the above solutions, wherein the format rules specify that the decoder is reinitialized when the grade, level, or layer of the encoded / decoded bitstream changes.

[0195] 15. The method described in any of the above solutions, wherein the format rules specify that the decoder is reinitialized when the timing parameters or assumed reference decoder parameter syntax in the codec bitstream changes.

[0196] 16. A video decoding apparatus, comprising a processor configured to implement one or more of the methods described in solutions 1 to 15.

[0197] 17. A video encoding apparatus comprising a processor configured to implement one or more of the methods described in solutions 1 to 15.

[0198] 18. A computer program product having computer code stored thereon, wherein the computer code, when executed by a processor, causes the processor to implement the method described in any one of solutions 1 to 15.

[0199] 19. A computer-readable medium having a bit stream recorded thereon in a bit stream format generated according to any one of solutions 1 to 15.

[0200] 20. A method comprising generating a bitstream according to any one of solutions 1 to 15 and writing the bitstream to a computer-readable medium.

[0201] 21. The methods, apparatus or systems described in this document.

[0202] In the solution described in this paper, the encoder conforms to the format rules by generating a codec representation based on those rules. In the solution described in this paper, the decoder can use the format rules to parse the syntax elements in the codec representation, determining the presence or absence of syntax elements according to the format rules to generate the decoded video.

[0203] In this document, the term "video processing" can refer to video encoding, video decoding, video compression, or video decompression. For example, a video compression algorithm can be applied during the conversion from the pixel representation of a video to the corresponding bitstream representation, and vice versa. As defined by the syntax, the bitstream representation of the current video block can (e.g.) correspond to bits that are co-occurring or scattered at different positions within the bitstream. For example, a macroblock can be encoded based on the error residual values ​​of the transformation and encoding / decoding, and also using bits in the header and other fields in the bitstream. Furthermore, during the conversion, the decoder can, based on this determination, parse the bitstream knowing that some fields may or may not be present, as described in the solutions above. Similarly, the encoder can determine whether certain syntax fields are included or excluded, and generate the codec representation accordingly by including or excluding syntax fields from the codec representation.

[0204] The disclosures and other schemes, examples, embodiments, modules, and functional operations described herein can be implemented in digital electronic circuits or in computer software, firmware, or hardware, containing the structures disclosed herein and their equivalents, or combinations thereof. The disclosed and other embodiments can be implemented as one or more computer program products encoded on a computer-readable medium, i.e., one or more computer program instruction modules for execution by a data processing apparatus or for controlling the operation of a data processing apparatus. The computer-readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a complex influencing machine-readable propagating signals, or combinations thereof. The term "data processing apparatus" encompasses all means, devices, and machines for processing data, including, for example, programmable processors, computers, or multiple processors or computers. In addition to hardware, the apparatus may also include code that creates an execution environment for the computer program in question, such as code constituting processor firmware, a protocol stack, a database management system, an operating system, or combinations thereof. Propagating signals are artificially generated signals, such as machine-generated electrical, optical, or electromagnetic signals, which are generated to encode information for transmission to a suitable receiver device.

[0205] Computer programs (also known as programs, software, software applications, scripts, or code) can be written in any programming language, including compiled or interpreted languages, and can be deployed in any form, including standalone programs or modules, components, subroutines, or other units suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple co-located files (e.g., a file storing one or more modules, subroutines, or code portions). A computer program can be deployed to execute on one computer or on multiple computers located at a single site or distributed across multiple sites and interconnected by a communications network.

[0206] The processes and logic flows described in this document can be performed by one or more programmable processors executing one or more computer programs to perform functions by manipulating input data and generating outputs. The processes and logic flows can also be performed by special-purpose logic circuitry (e.g., field-programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs)), and the apparatus can be implemented as special-purpose logic circuitry (e.g., FPGAs or ASICs).

[0207] Processors suitable for executing computer programs include, for example, both general-purpose and special-purpose microprocessors, and any one or more processors in any type of digital computer. Typically, a processor receives instructions and data from read-only memory or random access memory, or both. The basic components of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include one or more mass storage devices (e.g., magneto-optical, magneto-optical, or optical disc) for storing data, or operatively coupled to receive data from or transfer data to a mass storage device (e.g., magneto-optical, magneto-optical, or optical disc), or both. However, a computer does not necessarily need to have such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, including, for example, semiconductor memory devices (e.g., EPROM, EEPROM, and flash memory devices); magnetic disks (e.g., internal hard disks or removable disks); magneto-optical disks; and CD-ROM and DVD-ROM disks. Processors and memory may be supplemented by or incorporated into special-purpose logic circuitry.

[0208] While this patent document contains numerous details, these details should not be construed as limiting any subject matter or the scope of the claims, but rather as descriptions of features specific to particular embodiments of a particular art. In this patent document, certain features described in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately in multiple embodiments or in various suitable sub-combinations. Furthermore, although features may be described above as operating in certain combinations and even initially claimed in the same manner, in certain circumstances one or more features from the claimed combination may be removed from the combination, and the claimed combination may be for sub-combinations or variations thereof.

[0209] Similarly, although operations are depicted in a specific order in the accompanying drawings, this should not be construed as requiring such operations to be performed in the specific order or sequence shown, or to perform all the operations shown, in order to achieve the desired result. Furthermore, the separation of various system components in the embodiments described in this patent document should not be construed as requiring such separation in all embodiments.

[0210] Only a few implementations and examples are described, and other implementations, enhancements and variations can be made based on what is described and shown in this patent document.

[0211] When no intermediate component exists other than a line, trace, or other medium between the first and second components, the first component is directly coupled to the second component. When an intermediate component other than a line, trace, or other medium exists between the first and second components, the first component is indirectly coupled to the second component. The term "coupling" and its variations include direct coupling and indirect coupling. Unless otherwise stated, the term "about" means including a range of 10% of the following value.

[0212] While several embodiments have been provided in this disclosure, it should be understood that the disclosed systems and methods may be embodied in many other specific forms without departing from the spirit or scope of this disclosure. The present examples are intended to be illustrative rather than limiting and are not intended to be limited to the details given herein. For example, various elements or components may be combined or integrated into another system, or certain features may be omitted or not implemented.

[0213] Furthermore, without departing from the scope of this disclosure, the discrete or individual technologies, systems, subsystems, and methods described and illustrated in the various embodiments may be combined or integrated with other systems, modules, technologies, or methods. Other items shown or discussed as coupled may be directly connected or indirectly coupled or communicated via some interface, device, or intermediate component in an electrical, mechanical, or other manner. Those skilled in the art can identify other examples of changes, substitutions, and alterations, and these changes, substitutions, and alterations may be made without departing from the spirit and scope of the disclosure herein.

Claims

1. A method for processing video data, comprising: Receive bitstream, the bitstream signaling notification containing video decoder initialization information with a series of initialization parameters; and Based on the aforementioned series of initialization parameters, the conversion between visual media data and visual media data files is performed; The method is performed by the decoder, and the decoder is reinitialized when at least one of the general timing parameters and the assumed reference decoder (HRD) parameters is changed.

2. The method according to claim 1, wherein, The video decoder initialization information is signaled in at least one Decoding Capability Information (DCI) Network Abstraction Layer (NAL) unit in at least one bitstream.

3. The method according to claim 1, wherein, The video decoder initialization information is signaled in at least one Decoder Initialization Information (DII) Supplemental Enhancement Information (SEI) message in at least one bitstream.

4. The method according to claim 3, wherein, The DII SEI message needs to exist in the first access unit (AU) of the corresponding bit stream.

5. The method according to claim 1, wherein, The video decoder initialization information is signaled in the International Organization for Standardization (ISO) Basic Media File Format (ISOBMFF) file in the file-level frame, movie-level frame, at least one track-level frame, or a combination thereof.

6. The method according to claim 1, wherein, The video decoder initialization information is signaled in a file-level metadata frame, a movie-level metadata frame, a movie header frame, a sample description frame, a track header frame, a track group frame, a track-level metadata frame, or a combination thereof.

7. The method according to claim 1, wherein, The video decoder initialization information is signaled in the Dynamic Adaptive Streaming (DASH) Media Presentation Description (MPD) based on the Hypertext Transfer Protocol.

8. The method according to claim 1, wherein, The video decoder initialization information is signaled in an adaptive set, representation, or a combination thereof.

9. The method according to claim 1, wherein, The video decoder initialization information is signaled in the Real-Time Transport Protocol (RTP) header extension.

10. The method according to claim 1, wherein, The video decoder initialization information is signaled as part of a Session Description Protocol (SDP) proposal, an SDP response, or a combination thereof.

11. The method according to claim 1, wherein, The video decoder initialization information includes the maximum number of decoded images stored in the decoded image buffer (DPB) when decoding the bitstream (maxDecPics), the maximum decoded image width of the encoded and decoded images in the bitstream (maxDecPicW), the maximum decoded image height of the encoded and decoded images in the bitstream (maxDecPicH), or a combination thereof.

12. The method according to claim 1, wherein, The video decoder initialization information includes indications of the use of inter-layer prediction, reference image resampling, surround motion compensation, motion vector prediction from the reference image, palette encoding / decoding mode, adaptive color transformation, intra-frame block copying, adaptive loop filter (ALF) adaptive parameter set (APS) NAL unit, luminance mapping with chroma scaling (LMCS) APS NAL unit, scaling list APS NAL unit, or combinations thereof in the corresponding bitstream.

13. The method according to claim 1, wherein, The video decoder initialization information includes an indication of the maximum image sequence count between the current image and the corresponding reference image.

14. The method according to claim 1, wherein, The video decoder initialization information includes indications of the maximum color format, maximum bit depth, maximum codec image buffer size, smallest decoding unit (CU) size, scaling calculation information, or combinations thereof.

15. The method according to claim 1, wherein, The video decoder initialization information includes instructions for the use of deblocking, padding, sub-image segmentation, strip segmentation, slice segmentation, surround motion compensation, reference image resampling, long-term reference images, or combinations thereof.

16. The method according to claim 1, wherein, The video decoder initialization information includes the maximum layer that all codec video sequences (CVS) of the corresponding bitstream meet, the maximum level that all CVSs of the corresponding bitstream meet, or a combination thereof.

17. The method according to claim 1, wherein, The video decoder initialization information includes instructions for a video codec used to perform the conversion between the visual media data and the visual media data file.

18. The method according to claim 1, wherein, The video decoder initialization information includes the grade that all bitstreams meet.

19. The method according to any one of claims 1-18, wherein, The conversion includes generating the visual media data file based on the visual media data.

20. The method according to any one of claims 1-18, wherein the conversion includes parsing the visual media data file to obtain the visual media data.

21. An apparatus for processing video data, comprising a processor and a non-transitory memory having instructions thereon, wherein, When executed by the processor, the instructions cause the processor to perform the method of any one of claims 1-20.

22. A non-transitory computer-readable medium comprising a computer program product for use by a video codec apparatus, the computer program product including computer-executable instructions stored on the non-transitory computer-readable medium, such that the computer-executable instructions, when executed by a processor, cause the video codec apparatus to perform the method of any one of claims 1-20.

Images