Decoding parameter set in video codec

Abstract

Apparatus, systems, and methods for specifying syntax and semantics of a decoding parameter set (DPS) are described. An example method of video processing includes performing conversion between a video and a bitstream of the video, wherein the bitstream conforms to a format rule, the format rule specifying a data structure in a first access unit (AU) of the bitstream, wherein the first AU is located at the beginning of the bitstream, wherein the data structure is a network abstraction layer (NAL) unit.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is an application entering the Chinese national phase of International Patent Application No. PCT / US2020 / 067077 filed on December 26, 2020, which claims priority to U.S. Provisional Patent Application No. US 62 / 953,862 filed on December 26, 2019. The entire disclosure of the above application is incorporated by reference as part of the disclosure of this application. Technical Field

[0003] This patent document relates to video encoding and decoding technologies, systems, and devices. Background Art

[0004] Digital video accounts for the largest use of bandwidth on the Internet and other digital communications networks. As the number of connected user devices capable of receiving and displaying video increases, bandwidth demand for digital video usage is expected to continue to grow. Summary of the Invention

[0005] Devices, systems, and methods related to digital video coding and decoding are described, including specifying the syntax and semantics of a Decoding Parameter Set (DPS). The described methods can be applied to existing video coding standards (e.g., High Efficiency Video Coding (HEVC) and / or Versatile Video Coding (VVC)) and future video coding standards or video codecs.

[0006] In one representative aspect, the disclosed technology may be used to provide a video processing method, the method comprising: performing conversion between a video and a bitstream of the video, wherein the bitstream conforms to a format rule, wherein the format rule dictates that each of a plurality of decoding parameter set network abstraction layer (NAL) units in the bitstream have the same content, and wherein the decoding parameter sets include decoding capability information.

[0007] In another representative aspect, the disclosed technology may be used to provide a video processing method, the method comprising: performing conversion between a video and a bitstream of the video, wherein the bitstream conforms to a format rule, the format rule providing that a decoding parameter set does not include a first syntax element indicating an identifier of the decoding parameter set, and wherein the decoding parameter set includes decoding capability information.

[0008] In another representative aspect, the disclosed technology may be used to provide a video processing method, the method comprising: performing conversion between a video and a bitstream of the video; wherein the bitstream conforms to a format rule, the format rule dictating a data structure in a first access unit (AU) of the bitstream, wherein the first AU is located at the beginning of the bitstream, and wherein the data structure is a Network Abstraction Layer (NAL) unit.

[0009] In yet another representative aspect, the above method is embodied in the form of processor-executable code and stored in a computer-readable program medium.

[0010] In yet another representative aspect, a device is disclosed, the device being configured or operable to perform the above method. The device may include a processor programmed to implement the method.

[0011] In yet another representative aspect, a video decoder device may implement the method as described in this disclosure.

[0012] The above and other aspects and features of the disclosed technology are described in more detail in the drawings, the description, and the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a block diagram illustrating an example video processing system in which the various techniques of this disclosure may be implemented.

[0014] Figure 2 is a block diagram of an example hardware platform for video processing.

[0015] Figure 3 A block diagram illustrating an example video codec system in which some embodiments of the present disclosure may be implemented.

[0016] Figure 4 A block diagram illustrating an example of an encoder in which some embodiments of the present disclosure may be implemented.

[0017] Figure 5 A block diagram illustrating an example of a decoder in which some embodiments of the present disclosure may be implemented.

[0018] Figures 6 to 8 A flow chart illustrating an example method of video processing. DETAILED DESCRIPTION

[0019] Due to the increasing demand for higher-precision video, video coding and decoding methods and techniques are ubiquitous in modern technology. Video codecs typically consist of electronic circuits or software that compress or decompress digital video and are constantly being improved to provide greater coding and decoding efficiency. Video codecs convert uncompressed video into a compressed format and vice versa. There is a complex relationship between video quality, the amount of data used to represent the video (determined by the bitrate), the complexity of the encoding and decoding algorithms, sensitivity to data loss and errors, ease of editing, random access, and end-to-end delay (latency). Compression formats typically conform to standard video compression specifications, such as the High Efficiency Video Coding (HEVC) standard (also known as H.265 or MPEG-H Part 2), the yet-to-be-finalized versatile video codec standard, or other current and / or future video codec standards.

[0020] Embodiments of the disclosed technology can be applied to existing video codec standards (e.g., HEVC, H.265) and future standards to improve runtime performance. It is particularly relevant to the Merge mode in video codecs. Section headings are used in this document to improve readability and do not in any way limit the discussion or embodiments (and / or implementations) to the corresponding section.

[0021] 1. Overview of Example Embodiments

[0022] Embodiments of the disclosed technology are directed to specifying the syntax and semantics of a decoding parameter set (DPS). This technology can be applied to any video codec standard or non-standard video codec that supports single-layer and multi-layer video codecs, such as the Versatile Video Coding (VVC) under development. This technology can be applied to any video codec standard that supports splitting a picture into slices and sub-pictures, such as the Versatile Video Coding (VVC) under development, or any other video codec standard or video codec.

[0023] 2. List of abbreviations used in this document

[0024] APS (Adaptation Parameter Set)

[0025] AU (Access Unit)

[0026] AUD (Access Unit Delimiter) access unit delimiter

[0027] AVC (Advanced Video Coding)

[0028] CLVS (Coded Layer Video Sequence) codec layer video sequence

[0029] CPB (Coded Picture Buffer) codec picture buffer

[0030] CRA (Clean Random Access) Clean Random Access

[0031] CTU (Coding Tree Unit)

[0032] CVS (Coded Video Sequence) codec video sequence

[0033] DPB (Decoded Picture Buffer) decoded picture buffer

[0034] DPS (Decoding Parameter Set) decoding parameter set

[0035] EOB (End Of Bitstream) bitstream end

[0036] EOS (End Of Sequence) sequence ends

[0037] GDR (Gradual Decoding Refresh) gradual decoding refresh

[0038] HEVC (High Efficiency Video Coding)

[0039] IDR (Instantaneous Decoding Refresh) instant decoding refresh

[0040] JEM (Joint Exploration Model)

[0041] MCTS (Motion-Constrained Tile Sets)

[0042] NAL (Network Abstraction Layer)

[0043] OLS (Output Layer Set) output layer set

[0044] PH (Picture Header) picture header

[0045] PPS (Picture Parameter Set) picture parameter set

[0046] PTL (Profile, Tier and Level)

[0047] PU (Picture Unit)

[0048] RBSP (Raw Byte Sequence Payload)

[0049] SEI (Supplemental Enhancement Information)

[0050] SPS (Sequence Parameter Set) sequence parameter set

[0051] VCL (Video Coding Layer) video coding and decoding layer

[0052] VPS (Video Parameter Set) video parameter set

[0053] VTM (VVC Test Model)

[0054] VUI (Video Usability Information) video availability information

[0055] VVC (Versatile Video Coding) multifunctional video codec

[0056] 3. Preliminary discussion

[0057] Video codec standards are primarily developed through the well-known ITU-T and ISO / IEC standards. ITU-T developed H.261 and H.263, while ISO / IEC developed MPEG-1 and MPEG-4 Vision. 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 have been based on a hybrid video codec architecture that utilizes temporal prediction plus transform coding. To explore future video codec technologies beyond HEVC, VCEG and MPEG jointly established the Joint Video Exploration Team (JVET) in 2015. Since then, JVET has adopted many new approaches and incorporated them into reference software called the Joint Exploration Model (JEM). JVET meetings are held simultaneously every quarter, with the goal of achieving a 50% bitrate reduction compared to HEVC for the new codec standard. The new video codec standard was officially named Versatile Video Codec (VVC) at the JVET meeting in April 2018, and the first version of the VVC Test Model (VTM) was released at that time.

[0058] 3.1 Parameter Set

[0059] AVC, HEVC, and VVC specify parameter sets. Parameter set types include SPS, PPS, APS, VPS, and DPS. SPS and PPS are supported in all AVC, HEVC, and VVC implementations. VPS was introduced with HEVC and is included in both HEVC and VVC. APS and DPS are not included in AVC or HEVC, but are included in the latest VVC draft text.

[0060] SPS is designed to carry sequence-level header information, while PPS is designed to carry infrequently changing picture-level header information. Using SPS and PPS eliminates the need to repeat infrequently changing information for each sequence or picture, thus avoiding redundant signaling of this information. Furthermore, using SPS and PPS enables out-of-band transmission of important header information, eliminating the need for redundant transmission and improving error resilience.

[0061] VPS is introduced to carry sequence-level header information common to all layers in a multi-layer bitstream.

[0062] APS was introduced to carry such picture-level or slice-level information, which requires quite a lot of bits to encode and decode, can be shared by multiple pictures, and can have many different variations in a sequence.

[0063] DPS is introduced to carry bitstream level information, which indicates the highest capability required for decoding the entire bitstream.

[0064] 3.2 Tiers, layers and levels

[0065] Video codec standards typically specify profiles and levels. Some video codec standards also specify tiers, such as HEVC and the under-development VVC.

[0066] Profiles, tiers, and levels specify constraints on the bitstream, and therefore the capabilities required to decode the bitstream. Profiles, tiers, and levels can also be used to indicate points of interoperability between various decoder implementations.

[0067] Each profile specifies a subset of algorithmic features and restrictions that all decoders conforming to that profile should support. Note that encoders are not required to use all codecs or features supported in a profile, but decoders conforming to a profile are required to support all codecs or features.

[0068] Each level of the layer specifies a set of constraints on the values that bitstream syntax elements can take. The same set of layer and level definitions is typically used for all profiles, but individual implementations may support different layers and different levels within a layer for each supported profile. For any given profile, the layer levels typically correspond to specific decoder processing load and memory capabilities.

[0069] The capabilities of video decoders that conform to the video codec specification are specified based on the ability to decode video streams within the constraints of the profile, layer, and level specified in the video codec specification. When expressing the capabilities of a decoder for a specified profile, the layers and levels supported by that profile should also be expressed.

[0070] 3.3 Syntax and Semantics of Decoding Parameter Set (DPS) in VVC

[0071] In the latest VVC draft text in JVET-P2001-v14, which is publicly available here: http: / / phenix.int-evry.fr / jvet / doc_end_user / documents / 16_Geneva / wg11 / JVET-P2001-v14.zip, the DPS is specified as follows.

[0072] 7.3.2.1 Decoding parameter set syntax

[0073]

[0074] 7.4.3.1 Decoding parameter set RBSP semantics

[0075] The DPS RBSP shall be available for decoding before being referenced, and shall be included in at least one AU with TemporalId equal to 0 or provided externally.

[0076] NOTE 1 – The DPS NAL unit needs to be available to the decoding process (either in the bitstream or by external means) before it is referenced. However, the information contained in the DPS RBSP is not necessary for the operation of the decoding process specified in clauses 2 to 9 of this specification.

[0077] dps_decoding_parameter_set_id identifies the DPS for reference by other syntax elements. The value of dps_decoding_parameter_set_id shall not be equal to 0.

[0078] dps_max_sublayers_minus1 plus 1 specifies the maximum number of temporal sublayers that can be present in each CVS involving the DPS. The value of dps_max_sublayers_minus1 shall be in the range of 0 to 6, inclusive.

[0079] dps_reserved_zero_5bits shall be equal to 0 in bitstreams conforming to this version of this specification. Other values of dps_reserved_zero_5bits are reserved for future use by ITU-T | ISO / IEC.

[0080] dps_num_ptls_minus1 plus 1 specifies the number of profile_tier_level() syntax structures in the DPS.

[0081] When multiple profile_tier_level() syntax structures exist in the DPS, bitstream conformance requires that each CVS in the bitstream conform to at least one of the profile_tier_level() syntax structures.

[0082] dps_extension_flag equal to 0 specifies that the dps_extension_data_flag syntax element is not present in the DPS RBSP syntax structure. dps_extension_flag equal to 1 specifies that the dps_extension_data_flag syntax element is present in the DPS RBSP syntax structure.

[0083] The dps_extension_data_flag may have any value. Its presence and value do not affect the decoder's conformance to the profiles specified in Annex A. Decoders conforming to this version of this specification shall ignore all dps_extension_data_flag syntax elements.

[0084] 3.4 Syntax and Semantics of Profiles, Layers, and Levels (PTL) in VVC

[0085] In the latest VVC draft text in JVET-P2001-v14, the syntax and semantics of the profile_tier_level() syntax structure (one or more instances of which may be included in a DPS) are specified as follows.

[0086] 7.3.3.1 Common profile, layer and level syntax

[0087]

[0088]

[0089] 7.4.4.1 General profile, layer, and level semantics

[0090] The profile_tier_level() syntax structure provides level information and optionally profile, tier, sub-profile and general constraint information.

[0091] When the profile_tier_level() syntax structure is included in the DPS, OlsInScope is the OLS that includes all layers in the entire bitstream that references the DPS. When the profile_tier_level() syntax structure is included in the VPS, OlsInScope is the OLS that includes one or more OLSs specified by the VPS. When the profile_tier_level() syntax structure is included in the SPS, OlsInScope is the OLS that includes only the lowest layer among the layers that reference the SPS, and this lowest layer is an independent layer.

[0092] general_profile_idc indicates that OlsInScope conforms to the profile specified in Annex A. The bitstream shall not contain values of general_profile_idc other than those specified in Annex A. Other values of general_profile_idc are reserved for future use by ITU-T | ISO / IEC.

[0093] general_tier_flag specifies the tier context for the interpretation of general_level_idc specified in Annex A.

[0094] general_level_idc indicates that OlsInScope conforms to the level specified in Annex A. The bitstream shall not contain values of general_level_idc other than those specified in Annex A. Other values of general_level_idc are reserved for future use by ITU-T | ISO / IEC.

[0095] NOTE 1 - A larger value of general_level_idc indicates a higher level. The maximum level signaled for OlsInScope in DPS may be higher than the level signaled for CVS included in OlsInScope in SPS.

[0096] NOTE 2 – When OlsInScope conforms to multiple profiles, general_profile_idc shall indicate the profile that provides the preferred decoding result or preferred bitstream identification, as determined by the encoder (in a manner not specified in this specification).

[0097] NOTE 3 – When the profile_tier_level() syntax structure is included in the DPS and CVS of OlsInScope compliant with different profiles, general_profile_idc and level_idc shall indicate the profile and level of the decoder capable of decoding OlsInScope.

[0098] num_sub_profiles specifies the number of general_sub_profile_idc[i] syntax elements.

[0099] general_sub_profile_idc[i] indicates the i-th interoperability metadata registered according to Rec.ITU-T T.35. The content of Rec.ITU-T T.35 is not specified in this specification.

[0100] sublayer_level_present_flag[i] equal to 1 specifies that level information is present in the profile_tier_level() syntax structure of the sublayer representation with TemporalId equal to i. sublayer_level_present_flag[i] equal to 0 specifies that level information is not present in the profile_tier_level() syntax structure of the sublayer representation with TemporalId equal to i.

[0101] ptl_alignment_zero_bits shall be equal to 0.

[0102] The semantics of the syntax element sublayer_level_idc[i], except for the specification of the inference of the absence of a value, is the same as the syntax element general_level_idc, but applies to the sublayer representation with TemporalId equal to i.

[0103] When not present, the value of sublayer_level_idc[i] is inferred as follows:

[0104] – inferring sublayer_level_idc[maxNumSubLayersMinus1] to be equal to general_level_idc of the same profile_tier_level() structure,

[0105] – For i from maxNumSubLayersMinus1–1 to 0 (in decreasing order of the value of i, inclusive), sublayer_level_idc[i] is inferred to be equal to sublayer_level_idc[i+1].

[0106] 4. Disadvantages of existing implementation methods

[0107] The existing DPS design in VVC has the following problems:

[0108] (1) The DPS applies to the entire bitstream, and all SPSs referenced by codec pictures in the bitstream should reference the same DPS. However, there is no constraint requiring that all DPS NAL units in the bitstream should have the same content.

[0109] (2) Since the entire bitstream references the same DPS, the DPS ID referenced by the SPS is actually useless.

[0110] (3) In the latest VVC draft text, a DPS can appear in any AU. However, while it is useful to have a DPS at the beginning of the bitstream or in any AU that can be used as a random access point, for example, an AU containing IRAP pictures and GDR pictures, the presence of a DPS NAL unit in an AU that does not contain randomly accessible pictures or slices is useless. A randomly accessible slice is a slice with either an IRAP NAL unit type or a GDR NAL unit type.

[0111] (4) Since the DPS indicates the highest capability required to decode the entire bitstream, the profile_tier_level() syntax structure included in the DPS does not need to contain sublayer level information, which is carried by instances of the sublayer_level_idc[i] syntax element.

[0112] (5) When the profile_tier_level() syntax structure is included in a DPS, OlsInScope (i.e., the OLS to which the DPS applies) is defined as the OLS that includes all layers in the entire bitstream that references the DPS. However, there may not be an OLS that includes all layers in the entire bitstream.

[0113] 5. Example embodiments of the disclosed technology

[0114] The following detailed embodiments should be considered as examples to explain the general concept. These embodiments should not be interpreted narrowly. In addition, these embodiments can be combined in any way.

[0115] 1) To solve the first problem, it is required that all DPS NAL units with a specific value of dps_decoding_parameter_set_id in the bitstream should have the same content.

[0116] a. Alternatively, there is an additional requirement that all DPS NAL units in the bitstream should have the same dps_decoding_parameter_set_id value.

[0117] b. Alternatively, it is required (not an additional requirement) that all DPS NAL units in a bitstream should have the same dps_decoding_parameter_set_id value.

[0118] c. Alternatively, it is required that all DPS NAL units in the bitstream should have the same content.

[0119] 2) To address the second issue, the DPS ID (i.e., the dps_decoding_parameter_set_id syntax element) was removed from the DPS syntax, and thus the reference to the DPS ID in the SPS syntax (sps_decoding_parameter_set_id) was removed from the SPS syntax. In effect, the DPS then became an independent NAL unit rather than a parameter set. Therefore, the name of the DPS can be changed to "decoding parameter NAL unit." It is required that all decoding parameter NAL units in the bitstream must have the same content.

[0120] Alternatively, the DPS information can be signaled in a new SEI message, for example, named "Decoding Parameters SEI Message", and it is required that when an SEI NAL unit contains a Decoding Parameters SEI Message, it should not contain any other SEI messages. It is also required that all Decoding Parameters SEI messages in the bitstream must have the same content.

[0121] 3) To solve the third problem, the following constraints are stipulated:

[0122] When present in the bitstream, the DPS NAL unit shall be present in the first AU of the bitstream and may be present in any AU that has at least one codec slice NAL unit whose nal_unit_type is in the range from IDR_W_RADL to GDR_NUT (that NAL unit is an IRAP or GDR VCL NAL unit), inclusive, and shall not be present in any other AU.

[0123] Alternatively, replace the above “in any AU with at least one codec slice NAL unit whose nal_unit_type is in the range from IDR_W_RADL to GDR_NUT (the NAL unit is an IRAP or GDR VCL NAL unit), inclusive” with “in any AU with at least one IRAP or GDR picture”.

[0124] Alternatively, in either of the above two alternatives, the above “from IDR_W_RADL to GDR_NUT, including IDR_W_RADL and GDR_NUT” is replaced with “from IDR_W_RADL to RSV_IRAP_12, including IDR_W_RADL and RSV_IRAP_12”, i.e., the reserved IRAP NAL unit type is further included.

[0125] Alternatively, the same constraints are specified for the decoding parameter NAL unit (any of the above alternatives) by replacing the above "DPS NAL unit" with a "decoding parameter NAL unit".

[0126] Alternatively, the same constraints are specified for the SEI NAL unit containing the decoding parameters SEI message (any of the above alternatives) by replacing the above "DPS NAL unit" with "SEI NAL unit containing the decoding parameters SEI message".

[0127] 4) To solve the fourth problem, ensure that each profile_tier_level() syntax structure included in the DPS does not contain sub-tier level information.

[0128] This can be achieved by adding an input parameter to the PTL syntax structure to control whether sub-layer level information is signaled. For DPS, this parameter is 0 (i.e., no sub-layer level information), and for VPS and SPS, this parameter is 1.

[0129] b. Alternatively, this purpose is achieved by requiring sublayer_level_present_flag[i] to be equal to 0 for each i in each PTL syntax structure in the DPS (or decoding parameter NAL unit, or SEI NAL unit containing a decoding parameter SEI message).

[0130] 5) To solve the fifth problem, the following constraints are specified:

[0131] Each OLS in the CVS in the bitstream shall conform to at least one PTL syntax structure in the DPS (as part of the DPS semantics).

[0132] And accordingly, the semantics of the PTL syntax structure regarding OlsInScope has been changed: "When the profile_tier_level() syntax structure is included in the DPS, OlsInScope is one or more unidentified OLSs in one or more unidentified CVSs in the bitstream."

[0133] Note that the DPS does not need to contain the optimal PTL information for all OLSs. For example, when there are OLSs at levels 3, 4, and 5, assuming that the other PTL information for the OLSs is the same, it is sufficient to include only one PTL syntax structure indicating level 5 in the DPS, because an OLS that correctly conforms to a particular level also conforms to any higher level.

[0134] The same constraints apply to alternatives where the DPS is replaced by a decoding parameter NAL unit or a decoding parameter SEI message.

[0135] 6. Additional Example Embodiments

[0136] Below are some example embodiments that can be applied to the VVC specification. The modified text is based on the latest VVC text in JVET-P2001-v14. New additions, modifications, and the most relevant sections are double-underlined. Some other changes are editorial in nature and are therefore not shown or marked as different.

[0137] 6.1 First embodiment

[0138] 6.1.1DPS Syntax and Semantics

[0139] 7.3.2.1 Decoding parameter set syntax

[0140]

[0141] 7.4.3.1 Decoding parameter set RBSP semantics

[0142] The DPS RBSP shall be available for decoding before being referenced, and shall be included in at least one AU with TemporalId equal to 0 or provided externally.

[0143] NOTE 1 – The DPS NAL unit needs to be available to the decoding process (either in the bitstream or by external means) before it is referenced. However, the information contained in the DPS RBSP is not necessary for the operation of the decoding process specified in clauses 2 to 9 of this specification.

[0144]

[0145]

[0146] dps_decoding_parameter_set_id identifies the DPS for reference by other syntax elements. The value of dps_decoding_parameter_set_id should be greater than 0.

[0147] dps_max_sublayers_minus1 plus 1 specifies the maximum number of temporal sublayers that can be present in a layer in the bitstream. The value of dps_max_sublayers_minus1 shall be in the range of 0 to 6, inclusive.

[0148] dps_reserved_zero_5bits shall be equal to 0 in bitstreams conforming to this version of this specification. Other values of dps_reserved_zero_5bits are reserved for future use by ITU-T | ISO / IEC.

[0149] dps_num_ptls_minus1 plus 1 specifies the number of profile_tier_level() syntax structures in the DPS.

[0150]

[0151] dps_extension_flag equal to 0 specifies that the dps_extension_data_flag syntax element is not present in the DPS RBSP syntax structure. dps_extension_flag equal to 1 specifies that the dps_extension_data_flag syntax element is present in the DPS RBSP syntax structure.

[0152] The dps_extension_data_flag may have any value. Its presence and value do not affect the decoder's conformance to the profiles specified in Annex A. Decoders conforming to this version of this specification shall ignore all dps_extension_data_flag syntax elements.

[0153] 6.1.2PTL Syntax and Semantics

[0154] 7.3.3.1 Common profile, layer and level syntax

[0155]

[0156]

[0157] 7.4.4.1 General profile, layer, and level semantics

[0158] The profile_tier_level() syntax structure provides level information and optionally profile, tier, sub-profile and general constraint information.

[0159] When the VPS contains the profile_tier_level() syntax structure, OlsInScope is one or more OLSs specified by the VPS. When the SPS contains the profile_tier_level() syntax structure, OlsInScope is the OLS that only contains the lowest layer among the layers referenced by the SPS, and the lowest layer is an independent layer. ...

[0161] 7. Example Implementations of the Disclosed Technology

[0162] Figure 1 1 is a block diagram illustrating an example video processing system 1000 that can implement various techniques of the present disclosure. Various embodiments may include some or all of the components of system 1000. System 1000 may include an input 1002 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 may be received in a compressed or encoded format. Input 1002 may represent a network interface, a peripheral bus interface, or a storage interface. Examples of network interfaces include wired interfaces such as Ethernet, a passive optical network (PON), and wireless interfaces such as Wi-Fi or a cellular interface.

[0163] System 1000 may include a codec component 1004 that implements the various codecs or encoding methods described in this document. Codec component 1004 can reduce the average bit rate of the video from input 1002 to the output of codec component 1004 to generate a codec representation of the video. Therefore, codec technology is sometimes referred to as video compression or video transcoding technology. The output of codec component 1004 can be stored or transmitted via connected communications, as shown in component 1006. The stored or transmitted bitstream (or codec) representation of the video received at input 1002 can be used by component 1008 to generate pixel values or displayable video sent to display interface 1010. The process of generating user-visible video from the bitstream is sometimes referred to as video decompression. In addition, although some video processing operations are referred to as "codec" operations or tools, it should also be recognized that codec tools or operations are used for encoders, and corresponding decoding tools or operations that reverse the codec results will be performed by decoders.

[0164] Examples of peripheral bus interfaces or display interfaces may include Universal Serial Bus (USB), High-Definition Multimedia Interface (HDMI), or DisplayPort, etc. Examples of storage interfaces include SATA (Serial Advanced Technology Attachment), PCI, IDE interfaces, etc. The technology described in this document may be embodied in various electronic devices, such as mobile phones, laptop computers, smart phones, or other devices capable of performing digital data processing and / or video display.

[0165] Figure 2 2 is a block diagram of a video processing device 2000. The device 2000 may be used to implement one or more methods described in this document. The device 2000 may be embodied in a smartphone, a tablet, a computer, an Internet of Things (IoT) receiver, etc. The device 2000 may include one or more processors 2002, one or more memories 2004, and video processing hardware 2006. The processor 2002 may be configured to implement one or more methods described in this document (e.g., Figure 6-Figure 8 ). Memory 2004 can be used to store data and code used to implement the methods and techniques described herein. In hardware circuits, video processing hardware 2006 can be used to implement some of the techniques described in this document.

[0166] Figure 3 FIG. 1 is a block diagram illustrating an example video encoding and decoding system 100 that may utilize the techniques of this disclosure. Figure 3As shown, video codec system 100 may include source device 110 and target device 120. Source device 110 generates encoded video data, which may be referred to as a video encoding device. Target device 120 may decode the encoded video data generated by source device 110, which may be referred to as a video decoding device. Source device 110 may include a video source 112, a video encoder 114, and an input / output (I / O) interface 116.

[0167] The video source 112 may include sources such as a video capture device, an interface for receiving video data from a video content provider, and / or a computer graphics system for generating video data, or a combination of these sources. The video data may include one or more pictures. The video encoder 114 encodes the video data from the video source 112 to generate a bitstream. The bitstream may include a sequence of bits that form a codec representation of the video data. The bitstream may include a codec picture and associated data. The codec picture is a codec representation of the picture. The associated data may include a sequence parameter set, a picture parameter set, and other syntax structures. The I / O interface 116 may include a modulator / demodulator (modem) and / or a transmitter. The encoded video data may be sent directly to the target device 120 via the network 130a via the I / O interface 116. The encoded video data may also be stored on a storage medium / server 130b for access by the target device 120.

[0168] Target device 120 may include an I / O interface 126 , a video decoder 124 , and a display device 122 .

[0169] I / O interface 126 may include a receiver and / or a modem. I / O interface 126 may obtain encoded video data from source device 110 or storage medium / server 130b. Video decoder 124 may decode the encoded video data. Display device 122 may display the decoded video data to a user. Display device 122 may be integrated with target device 120 or may be external to target device 120, with target device 120 configured to interface with an external display device.

[0170] The video encoder 114 and the video decoder 124 may operate according to a video compression standard, such as the High Efficiency Video Codec (HEVC) standard, the Versatile Video Codec (VVC) standard, and other current and / or future standards.

[0171] Figure 4 To illustrate a block diagram of an example of a video encoder 200, the video encoder 200 may be as follows: Figure 3 The video encoder 114 in the system 100 is shown.

[0172] Video encoder 200 may be configured to perform any or all of the techniques of this disclosure. Figure 4In the example of , video encoder 200 includes multiple functional components. The techniques described in this disclosure can be shared among the various components of video encoder 200. In some examples, a processor can be configured to perform any or all of the techniques described in this disclosure.

[0173] The functional components of the video encoder 200 may include a segmentation unit 201, a prediction unit 202 (which may include a mode selection unit 203, a motion estimation unit 204, a motion compensation unit 205 and an intra-frame prediction unit 206), a residual generation unit 207, a transform unit 208, a quantization unit 209, an inverse quantization unit 210, an inverse transform unit 211, a reconstruction unit 212, a buffer 213 and an entropy coding unit 214.

[0174] In other examples, the video encoder 200 may include more, fewer, or different functional components. In one example, the prediction unit 202 may include an intra block copy (IBC) unit. The IBC unit may perform prediction in an IBC mode where at least one reference picture is a picture in which the current video block is located.

[0175] Furthermore, some components such as the motion estimation unit 204 and the motion compensation unit 205 may be highly integrated but are shown for the purpose of explanation. Figure 4 In the example, they are represented separately.

[0176] The partitioning unit 201 may partition a picture into one or more video blocks. The video encoder 200 and the video decoder 300 may support various video block sizes.

[0177] The mode selection unit 203 can select one of the coding modes (intra or inter, for example, based on the error result) and provide the resulting intra or inter coded block to the residual generation unit 207 to generate residual block data and to the reconstruction unit 212 to reconstruct the coded block for use as a reference picture. In some examples, the mode selection unit 203 can select a combined intra and inter prediction (CIIP) mode, where prediction is based on an inter prediction signal and an intra prediction signal. In the case of inter prediction, the mode selection unit 203 can also select the precision of the motion vector (e.g., sub-pixel or integer pixel precision) for the block.

[0178] To perform inter-frame prediction on the current video block, the motion estimation unit 204 may generate motion information for the current video block by comparing the current video block with one or more reference frames from the buffer 213. The motion compensation unit 205 may determine a predicted video block for the current video block based on the motion information and decoded samples of pictures other than the picture associated with the current video block from the buffer 213.

[0179] Motion estimation unit 204 and motion compensation unit 205 may perform different operations on the current video block, eg, depending on whether the current video block is in an I slice, a P slice, or a B slice.

[0180] In some examples, motion estimation unit 204 may perform unidirectional prediction for the current video block, and motion estimation unit 204 may search the reference pictures in list 0 or list 1 to find a reference video block for the current video block. Motion estimation unit 204 may then generate a reference index indicating the reference picture in list 0 or list 1 containing 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 204 may output the reference index, prediction direction indicator, and motion vector as motion information for the current video block. Motion compensation unit 205 may generate a predicted video block for the current block based on the reference video block indicated by the motion information for the current video block.

[0181] In other examples, the motion estimation unit 204 may perform bidirectional prediction for the current video block. The motion estimation unit 204 may search for a reference video block for the current video block in the reference pictures in list 0 and may also search for another reference video block for the current video block in the reference pictures in list 1. The motion estimation unit 204 may then generate reference indexes indicating reference pictures in list 0 and list 1, which include reference video blocks and motion vectors indicating spatial displacements between the reference video blocks and the current video block. The motion estimation unit 204 may output the reference index and motion vector for the current video block as motion information for the current video block. The motion compensation unit 205 may generate a predicted video block for the current video block based on the reference video block indicated by the motion information for the current video block.

[0182] In some examples, motion estimation unit 204 may output a complete set of motion information for use in a decoding process by a decoder.

[0183] In some examples, motion estimation unit 204 may not output a complete set of motion information for the current video. Instead, motion estimation unit 204 may reference motion information of another video block to signal the motion information for the current video block. For example, motion estimation unit 204 may determine that the motion information for the current video block is sufficiently similar to the motion information for a neighboring video block.

[0184] In one example, motion estimation unit 204 may indicate a value in a syntax structure associated with the current video block that indicates to video decoder 300 that the current video block has the same motion information as another video block.

[0185] In another example, motion estimation unit 204 may identify another video block and a motion vector difference (MVD) in a syntax structure associated with the current video block. The motion vector difference represents the difference between the motion vector of the current video block and the motion vector of the indicated video block. Video decoder 300 may use the motion vector of the indicated video block and the motion vector difference to determine the motion vector of the current video block.

[0186] As described above, the video encoder 200 may predictively signal motion vectors. Two examples of predictive signaling techniques that may be implemented by the video encoder 200 include advanced motion vector prediction (AMVP) and merge mode signaling.

[0187] The intra-frame prediction unit 206 can perform intra-frame prediction on the current video block. When the intra-frame prediction unit 206 performs intra-frame prediction on the current video block, the intra-frame prediction unit 206 can generate prediction data for the current video block based on decoded samples of other video blocks in the same picture. The prediction data for the current video block may include a predicted video block and various syntax elements.

[0188] The residual generation unit 207 can generate residual data for the current video block by subtracting (e.g., indicated by a minus sign) the predicted video block of the current video block from the current video block. The residual data for the current video block may include a residual video block corresponding to different sample components of the samples in the current video block.

[0189] In other examples, there may be no residual data for the current video block, such as in skip mode, and the residual generation unit 207 may not perform the subtraction operation.

[0190] Transform processing unit 208 may generate one or more transform coefficient video blocks for the current video block by applying one or more transforms to the residual video block associated with the current video block.

[0191] After transform processing unit 208 generates a transform coefficient video block associated with the current video block, quantization unit 209 may 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.

[0192] The inverse quantization unit 210 and the inverse transform unit 211 may apply inverse quantization and inverse transform, respectively, to the transform coefficient video block to reconstruct a residual video block from the transform coefficient video block. The reconstruction unit 212 may add the reconstructed residual video block to corresponding samples from one or more prediction video blocks generated by the prediction unit 202 to generate a reconstructed video block associated with the current block for storage in the buffer 213.

[0193] After the reconstruction unit 212 reconstructs the video block, a loop filtering operation may be performed to reduce video block artifacts in the video block.

[0194] The entropy coding unit 214 may receive data from other functional components of the video encoder 200. When the entropy coding unit 214 receives data, the entropy coding unit 214 may perform one or more entropy coding operations to generate entropy-coded data and output a bitstream including the entropy-coded data.

[0195] Figure 5 To illustrate an example block diagram of a video decoder 300, the video decoder 300 may be Figure 3 The video decoder 114 in the system 100 is shown in FIG.

[0196] Video decoder 300 can be configured to perform any or all of the techniques of this disclosure. Figure 5 In the example of FIG, video decoder 300 includes multiple functional components. The techniques described in this disclosure can be shared among the various components of video decoder 300. In some examples, a processor can be configured to perform any or all of the techniques described in this disclosure.

[0197] exist Figure 5 In the example of FIG, the video decoder 300 includes an entropy decoding unit 301, a motion compensation unit 302, an intra-frame prediction unit 303, an inverse quantization unit 304, an inverse transform unit 305, a reconstruction unit 306, and a buffer 307. In some examples, the video decoder 300 can perform operations generally related to the video encoder 200 (e.g., Figure 4 ) describes the encoding pass and the corresponding decoding pass.

[0198] The entropy decoding unit 301 can retrieve an encoded bitstream. The encoded bitstream may include entropy-encoded video data (e.g., encoded video data blocks). The entropy decoding unit 301 can decode the entropy-encoded video data, and based on the entropy-decoded video data, the motion compensation unit 302 can determine motion information including motion vectors, motion vector precision, reference picture list index, and other motion information. For example, the motion compensation unit 302 can determine this information by performing AMVP and merge modes.

[0199] The motion compensation unit 302 may generate a motion compensated block, possibly performing interpolation based on an interpolation filter. An identifier of the interpolation filter used with sub-pixel precision may be included in a syntax element.

[0200] Motion compensation unit 302 may calculate interpolated values for sub-integer pixels of a reference block using interpolation filters used by video encoder 20 during encoding of the video block. Motion compensation unit 302 may determine the interpolation filters used by video encoder 200 from received syntax information and use the interpolation filters to produce a prediction block.

[0201] The motion compensation unit 302 may use some syntax information to determine the size of blocks used to encode frames and / or slices of the coded video sequence, partitioning information describing how each macroblock of a picture of the coded video sequence is partitioned, a mode indicating how each partition is encoded, one or more reference frames (and reference frame lists) for each inter-frame coded block, and other information for decoding the coded video sequence.

[0202] The intra prediction unit 303 can form a prediction block from spatially neighboring blocks using, for example, an intra prediction mode received in the bitstream. The inverse quantization unit 303 inversely quantizes, i.e., dequantizes, the quantized video block coefficients provided in the bitstream and decoded by the entropy decoding unit 301. The inverse transform unit 303 applies an inverse transform.

[0203] The reconstruction unit 306 may add the residual block to the corresponding prediction block generated by the motion compensation unit 202 or the intra-frame prediction unit 303 to form a decoded block. If necessary, a deblocking filter may be applied to the decoded block to remove blocking artifacts. The decoded video block is then stored in a buffer 307, which provides reference blocks for subsequent motion compensation / intra-frame prediction and also produces decoded video for presentation on a display device.

[0204] Figures 6 to 8 An example method for implementing the above technical solution is shown. For example, Figures 1 to 5 Shown in.

[0205] Figure 6 A flow chart of an example method 600 for video processing is shown. The method 600 includes, at operation 610, performing conversion between a video and a bitstream of the video, the bitstream conforming to a format rule, the format rule specifying that each of a plurality of decoding parameter set network abstraction layer (NAL) units in the bitstream has the same content, and wherein the decoding parameter sets include decoding capability information.

[0206] Figure 7A flow chart of an example method 700 for video processing is shown. The method 700 includes, at operation 710, performing conversion between a video and a bitstream of the video, the bitstream conforming to a format rule, the format rule specifying that a decoding parameter set does not include a first syntax element indicating an identifier of the decoding parameter set, and wherein the decoding parameter set includes decoding capability information.

[0207] Figure 8 A flow chart of an example method 800 for video processing is shown. The method 800 includes, at operation 810, performing conversion between a video and a bitstream of the video, the bitstream conforming to a format rule, the format rule specifying a data structure in a first access unit (AU) of the bitstream, wherein the first AU is located at the beginning of the bitstream, wherein the data structure is a network abstraction layer (NAL) unit.

[0208] The following provides a list of preferred solutions for some embodiments.

[0209] 1. A video processing method, comprising: performing conversion between a video and a bitstream of the video, wherein the bitstream conforms to a format rule, wherein the format rule specifies that each of a plurality of decoding parameter set network abstraction layer (NAL) units in the bitstream has the same content, and wherein the decoding parameter set includes decoding capability information.

[0210] 2. The method of solution 1, wherein each of the plurality of decoding parameter set NAL units includes a syntax element having a first value.

[0211] 3. The method of solution 1, wherein each of the plurality of decoding parameter set NAL units includes a syntax element having a common value.

[0212] 4. The method as described in solution 2 or 3, wherein the syntax element in the bitstream is dps_decoding_parameter_set_id.

[0213] 5. A video processing method, comprising: performing conversion between a video and a bitstream of the video, wherein the bitstream conforms to a format rule, the format rule providing that a decoding parameter set does not include a first syntax element indicating an identifier of the decoding parameter set, and wherein the decoding parameter set includes decoding capability information.

[0214] 6. The method of solution 5, wherein the format rule further stipulates that the decoding parameter set is included in a network abstraction layer (NAL) unit.

[0215] 7. The method of solution 6, wherein the decoding parameter set is referred to as a decoding parameter network abstraction layer (NAL) unit based on excluding the first syntax element.

[0216] 8. The method of solution 5, wherein the format rule further specifies that information associated with the decoding parameter set is included in a Supplemental Enhancement Information (SEI) message.

[0217] 9. The method of solution 7 or 8, wherein the format rule further stipulates that a sequence parameter set (SPS) does not reference a decoding parameter set by including a second syntax element, the second syntax element indicating an identifier of the decoding parameter set referenced by the SPS.

[0218] 10. The method of solution 9, wherein the first syntax element and the second syntax element are dps_decoding_parameter_set_id and sps_decoding_parameter_set_id respectively.

[0219] 11. The method of solution 7, wherein each of the plurality of decoding parameter NAL units in the bitstream has common content.

[0220] 12. The method of solution 8, wherein the SEI network abstraction layer (NAL) unit including the SEI message does not include other SEI messages.

[0221] 13. The method of solution 8, wherein each of the plurality of SEI messages including information associated with a decoding parameter set includes common content.

[0222] 14. A video processing method comprising: performing conversion between a video and a bitstream of the video, wherein the bitstream conforms to a format rule, the format rule specifying that a data structure is in a first access unit (AU) of the bitstream, wherein the first AU is located at the beginning of the bitstream, and wherein the data structure is a network abstraction layer (NAL) unit.

[0223] 15. The method of solution 14, wherein the data structure is in a second AU, and the second AU includes at least one codec slice NAL unit having a nal_unit_type within a predetermined range.

[0224] 16. The method of solution 15, wherein the predetermined range is from IDR_W_RADL to GDR_NUT.

[0225] 17. The method of solution 15, wherein the predetermined range is from IDR_W_RADL to RSV_IRAP_12.

[0226] 18. The method of any of solutions 14 to 17, wherein the data structure is a decoding parameter set network abstraction layer (NAL) unit, and wherein the decoding parameter set includes decoding capability information.

[0227] 19. The method of solution 14 or 15, wherein the data structure is a decoding parameter Network Abstraction Layer (NAL) unit.

[0228] 20. The method of solution 14 or 15, wherein the data structure is a Supplemental Enhancement Information (SEI) Network Abstraction Layer (NAL) unit including a decoding parameter SEI message.

[0229] 21. The method of any one of solutions 1 to 20, wherein converting comprises decoding the video from a bitstream.

[0230] 22. The method of any one of solutions 1 to 20, wherein the conversion comprises encoding the video into a bitstream.

[0231] 23. A method for storing a bitstream representing a video to a computer-readable recording medium, comprising: generating a bitstream from the video according to any one or more of the methods described in solutions 1 to 20; and writing the bitstream to the computer-readable recording medium.

[0232] 24. A video processing device comprising a processor configured to implement the method according to any one or more of solutions 1 to 23.

[0233] 25. A computer-readable medium having instructions stored thereon, which, when executed, cause a processor to implement the method of any one or more of solutions 1 to 23.

[0234] 26. A computer-readable medium storing a bitstream generated according to any one or more of solutions 1 to 23.

[0235] 27. A video processing device storing a bitstream, wherein the video processing device is configured to implement any one or more of the methods described in solutions 1 to 23.

[0236] Another list of preferred solutions for some embodiments is provided next.

[0237] P1. A video processing method comprising: for a conversion between a current video segment of a video and a bitstream representation of the video, determining that each of a plurality of decoding parameter set (DPS) network abstraction layer (NAL) units including a syntax element having a first value has common content; and performing the conversion based on the determination.

[0238] P2. A video processing method comprising: for a conversion between a current video segment of a video and a bitstream representation of the video, determining that a syntax element of each of a plurality of decoding parameter set (DPS) network abstraction layer (NAL) units includes a common value; and performing the conversion based on the determination.

[0239] P3. The method as described in solution P1 or P2, wherein the syntax element in the bitstream representation is dps_decoding_parameter_set_id.

[0240] P4. A video processing method comprising: for a conversion between a current video segment of a video and a bitstream representation of the video, determining that each of a plurality of decoding parameter set (DPS) network abstraction layer (NAL) units includes common content; and performing the conversion based on the determination.

[0241] P5. The method of any of solutions P1 to P4, wherein the decoding parameter set (DPS) applies to the entire bitstream representation.

[0242] P6. A video processing method, comprising: for a conversion between a current video segment of a video and a bitstream representation of the video, making a decision to exclude a first syntax element from a decoding parameter set (DPS) in the bitstream representation and, thereby, excluding a second syntax element from a sequence parameter set (SPS) in the bitstream representation; and performing the conversion based on the decision.

[0243] P7. The method as described in solution P6, wherein the first syntax element and the second syntax element are dps_decoding_parameter_set_id and sps_decoding_parameter_set_id respectively.

[0244] P8. The method of solution P6 or P7, wherein the DPS is referred to as a decoding parameter network abstraction layer (NAL) unit.

[0245] P9. The method of solution P8, wherein each decoding parameter NAL unit in the bitstream representation includes common content.

[0246] P10. A video processing method, comprising: for a conversion between a current video segment of a video and a bitstream representation of the video, configuring the bitstream representation to include a supplemental enhancement information (SEI) message, the SEI message including information associated with decoding parameters; determining that an SEI network abstraction layer (NAL) unit including the SEI message does not include other SEI messages; and performing the conversion using the SEI NAL unit.

[0247] P11. The method of solution P10, wherein each of the plurality of SEI messages including information associated with decoding parameters includes common content.

[0248] P12. A video processing method comprising: for a bitstream representation of a video including a decoding parameter set (DPS) network abstraction layer (NAL) unit, determining that the DPS NAL unit is in a first access unit (AU) of the bitstream representation, wherein the first AU is located at the beginning of the bitstream representation; and based on the determination, performing a conversion between a current video segment of the video and the bitstream representation.

[0249] P13. The method of solution P12, wherein the DPS NAL unit is in a second AU, the second AU including at least one codec slice NAL with a nal_unit_type within a predetermined range.

[0250] P14. The method of solution P13, wherein the predetermined range is from IDR_W_RADL to GDR_NUT.

[0251] P15. The method of solution P13, wherein the predetermined range is from IDR_W_RADL to RSV_IRAP_12.

[0252] P16. A video processing method, comprising: for a conversion between a current video segment of a video and a bitstream representation of the video, determining that a profile tier layer (PTL) syntax structure included in a decoding parameter set (DPS) in the bitstream representation does not include sub-layer level information; and performing the conversion based on the determination.

[0253] P17. The method of solution P16, wherein the determination is based on a single bit input parameter in the PTL syntax structure.

[0254] P18. The method of solution P17, wherein for DPS, a single bit is 0.

[0255] P19. The method of solution P17, wherein for a video parameter set (VPS) and a sequence parameter set (SPS) in the bitstream representation, a single bit is 1.

[0256] P20. A video processing method, comprising: for a conversion between a current video segment of a video and a bitstream representation of the video, determining that each output layer set (OLS) in a codec video sequence (CVS) in the bitstream representation conforms to at least one profile layer (PTL) syntax structure included in a decoding parameter set (DPS) in the bitstream representation; and performing the conversion based on the determination.

[0257] P21. The method of any one of solutions P1 to P20, wherein the conversion generates the current video segment from a bitstream representation.

[0258] P22. The method of any one of solutions P1 to P20, wherein the conversion generates a bitstream representation from the current video segment.

[0259] P23. A method as described in any one of solutions P1 to P22, wherein the current video segment is a current slice, a current block, a current slice or a current sub-picture.

[0260] P24. A video processing device comprising a processor configured to implement the method described in any one or more of solutions P1 to P23.

[0261] P25. A computer-readable recording medium having a program including codes recorded thereon, the program being configured to cause a processor to execute the method according to any one of solutions P1 to P23.

[0262] P26. A computer program product stored on a non-transitory computer-readable medium, the computer program product comprising a program code for executing the method of any one of solutions P1 to P23.

[0263] In this document, the term "video processing" may refer to video encoding, video decoding, video compression, or video decompression. For example, a video compression algorithm may be applied during the conversion from a pixel representation of a video to a corresponding bitstream, or vice versa. The bitstream for a current video block may, for example, correspond to bits that are co-located or distributed across different locations within the bitstream, as defined by the syntax. For example, a macroblock may be encoded based on error residual values from transforms and codecs, and may also use bits in the header and other fields in the bitstream.

[0264] The disclosed and other solutions, examples, embodiments, modules, and functional operations described in this document can be implemented in digital electronic circuitry or computer software, firmware, or hardware, including the structures disclosed in this document and their structural equivalents, or any combination thereof. The disclosed and other embodiments can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a computer-readable medium, for execution or control by a data processing apparatus. The computer-readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition of matter that effects a machine-readable propagated signal, or any combination thereof. The term "data processing apparatus" encompasses all apparatus, devices, and machines that process data, including, for example, a programmable processor, a computer, 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 any combination thereof. A propagated signal is an artificially generated signal, such as a machine-generated electrical, optical, or electromagnetic signal, that is generated to encode information for transmission to a suitable receiver device.

[0265] A computer program (also referred to as a program, software, software application, script, or code) may be written in any form of programming language (including compiled or interpreted languages) and may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program may be stored as part 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 coordinated files (e.g., files storing one or more modules, subroutines, or portions of code). A computer program may be deployed to execute on one computer or on multiple computers located at one location or distributed across multiple locations and interconnected by a communications network.

[0266] The processes and logic flows described in this document may be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows may also be performed by, and implemented as, special purpose logic circuitry, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC).

[0267] Processors suitable for executing computer programs include general-purpose and special-purpose microprocessors, as well as any one or more processors of any kind of digital computer. Typically, a processor will receive instructions and data from read-only memory or random-access memory, or both. The essential elements 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, or be operatively coupled to, one or more mass storage devices for storing data, such as magnetic, magneto-optical, or optical disks, to receive data from or transfer data to one or more mass storage devices, or both. However, a computer need not have such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of nonvolatile memory, media, and storage devices, including, for example, semiconductor memory devices such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard drives or removable disks; magneto-optical disks; and CD ROM and DVD-ROM disks. The processor and memory may be supplemented by, or incorporated in, special-purpose logic circuitry.

[0268] Although this patent document contains many details, these details should not be interpreted as limitations on any invention or the scope of what may be claimed, but rather as descriptions of features that may be specific to a particular embodiment of a particular invention. Certain features described in this patent document in the context of separate 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 any suitable subcombination. Furthermore, although features may be described above as functioning in certain combinations and even initially claimed as such, in some cases one or more features in the claimed combination may be excluded from the combination, and the claimed combination may involve a subcombination or a variation of a subcombination.

[0269] Similarly, while operations are depicted in a particular order in the drawings, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve the desired effect. Furthermore, the separation of various system components in the embodiments described in this patent document should not be understood as requiring such separation in all embodiments.

[0270] Only a few implementations and examples are described, and other implementations, enhancements, and variations can be made based on what is described and illustrated in this patent document.

Claims

1. A video processing method, comprising: Perform conversion between video and bitstream of said video, wherein the bitstream complies with a first format rule, wherein the first format rule stipulates that each of a plurality of network abstraction layer (NAL) units related to decoding parameters indicating decoding capability information in the bitstream has the same content; wherein the first format rule stipulates that a NAL unit related to decoding parameters indicating decoding capability information is in a first access unit (AU) of the bitstream, wherein the first AU is located at the beginning of the bitstream; and The first format rule further stipulates that a plurality of profile, layer and level (PTL) syntax structures are included in the original byte sequence payload of the NAL unit including the decoding capability information.

2. The method according to claim 1, wherein The NAL unit related to the decoding parameter indicating the decoding capability information is a Supplemental Enhancement Information (SEI) NAL unit indicating the decoding capability information.

3. The method according to claim 1 or 2, wherein: The first format rule further stipulates that since the decoding capability information is included in a NAL unit, the decoding capability information does not include a first syntax element indicating an identifier of the decoding capability information.

4. The method according to claim 3, wherein: The first format rule further stipulates that since the decoding capability information is included in the NAL unit, a sequence parameter set (SPS) does not reference the decoding capability information by including a second syntax element, the second syntax element indicating the identifier of the decoding capability information referenced by the SPS.

5. The method according to claim 1, wherein The converting includes decoding the video from the bitstream.

6. The method according to claim 1, wherein The converting includes encoding the video into the bitstream.

7. The method according to claim 1, wherein The bitstream conforms to a second format rule that specifies that a decoding parameter set does not include a third syntax element indicating an identifier of the decoding parameter set, and The decoding parameter set includes decoding capability information.

8. The method according to claim 7, wherein: The second format rule further provides for including the decoding parameter set in a Network Abstraction Layer (NAL) unit.

9. The method according to claim 8, wherein The decoding parameter set is referred to as a decoding parameter network abstraction layer (NAL) unit based on excluding the third syntax element.

10. The method according to claim 7, wherein: The second format rule further provides for including information associated with the decoding parameter set in a Supplemental Enhancement Information (SEI) message.

11. The method according to claim 9 or 10, wherein: The second format rule further stipulates that a sequence parameter set (SPS) does not reference the decoding parameter set by including a fourth syntax element indicating the identifier of the decoding parameter set referenced by the SPS.

12. The method according to claim 11, wherein The third syntax element and the fourth syntax element are dps_decoding_parameter_set_id and sps_decoding_parameter_set_id, respectively.

13. The method according to claim 9, wherein: Each of the plurality of decoding parameter NAL units in the bitstream has common content.

14. The method according to claim 10, wherein: The SEI network abstraction layer (NAL) unit including the SEI message does not include other SEI messages.

15. The method according to claim 10, wherein Each of the plurality of SEI messages including information associated with the decoding parameter set includes common content.

16. The method according to claim 1, wherein The bitstream conforms to a third format rule, which specifies that a data structure is in a first access unit (AU) of the bitstream, wherein the first AU is located at the beginning of the bitstream, and wherein the data structure is a network abstraction layer (NAL) unit.

17. The method according to claim 16, wherein The data structure is in a second AU, and the second AU includes at least one codec slice NAL unit having a nal_unit_type within a predetermined range.

18. The method according to claim 17, wherein: The predetermined range is from IDR_W_RADL to GDR_NUT.

19. The method according to claim 17, wherein The predetermined range is from IDR_W_RADL to RSV_IRAP_12.

20. The method according to any one of claims 16 to 19, wherein The data structure is a decoding parameter set network abstraction layer (NAL) unit, and wherein the decoding parameter set includes decoding capability information.

21. The method according to claim 16 or 17, wherein The data structure is a decoding parameter Network Abstraction Layer (NAL) unit.

22. The method according to claim 16 or 17, wherein: The data structure is a Supplemental Enhancement Information (SEI) Network Abstraction Layer (NAL) unit including a decoding parameter SEI message.

23. The method according to any one of claims 7 to 10 and 13 to 19, wherein: The converting includes decoding the video from the bitstream.

24. The method according to any one of claims 7 to 10 and 13 to 19, wherein: The converting includes encoding the video into the bitstream.

25. A video data processing apparatus comprising a processor and a non-transitory memory having instructions thereon, wherein: The instructions, when executed by the processor, cause the processor to: Perform conversion between video and bitstream of said video, wherein the bitstream complies with a first format rule, wherein the first format rule stipulates that each of a plurality of network abstraction layer (NAL) units related to decoding parameters indicating decoding capability information in the bitstream has the same content; wherein the first format rule stipulates that a NAL unit related to decoding parameters indicating decoding capability information is in a first access unit (AU) of the bitstream, wherein the first AU is located at the beginning of the bitstream; and The first format rule further stipulates that a plurality of profile, layer and level (PTL) syntax structures are included in the original byte sequence payload of the NAL unit including the decoding capability information.

26. The device according to claim 25, wherein The first format rule further stipulates that since the decoding capability information is included in a NAL unit, the decoding capability information does not include a first syntax element indicating an identifier of the decoding capability information.

27. The device according to claim 26, wherein The first format rule further stipulates that since the decoding capability information is included in the NAL unit, a sequence parameter set (SPS) does not reference the decoding capability information by including a second syntax element, the second syntax element indicating the identifier of the decoding capability information referenced by the SPS.

28. A non-transitory computer-readable storage medium having stored therein instructions that cause a processor to: Perform conversion between video and bitstream of said video, in, The bitstream complies with a first format rule, wherein the first format rule stipulates that each of a plurality of network abstraction layer (NAL) units related to decoding parameters indicating decoding capability information in the bitstream has the same content; wherein the first format rule stipulates that a NAL unit related to decoding parameters indicating decoding capability information is in a first access unit (AU) of the bitstream, wherein the first AU is located at the beginning of the bitstream; and The first format rule further stipulates that a plurality of profile, layer and level (PTL) syntax structures are included in the original byte sequence payload of the NAL unit including the decoding capability information.

29. The non-transitory computer-readable storage medium of claim 28, wherein: The first format rule further stipulates that since the decoding capability information is included in a NAL unit, the decoding capability information does not include a first syntax element indicating an identifier of the decoding capability information.

30. The non-transitory computer-readable storage medium of claim 29, wherein: The first format rule further stipulates that since the decoding capability information is included in the NAL unit, a sequence parameter set (SPS) does not reference the decoding capability information by including a second syntax element, the second syntax element indicating the identifier of the decoding capability information referenced by the SPS.

31. A non-transitory computer-readable recording medium storing a bit stream of a video generated by a method executed by a video processing apparatus, wherein: The method comprises: generating the bitstream of the video, wherein the bitstream complies with a first format rule, wherein the first format rule stipulates that each of a plurality of network abstraction layer (NAL) units related to decoding parameters indicating decoding capability information in the bitstream has the same content; wherein the first format rule stipulates that a NAL unit related to decoding parameters indicating decoding capability information is in a first access unit (AU) of the bitstream, wherein the first AU is located at the beginning of the bitstream; and The first format rule further stipulates that a plurality of profile, layer and level (PTL) syntax structures are included in the original byte sequence payload of the NAL unit including the decoding capability information.

32. The non-transitory computer-readable recording medium according to claim 31, wherein The first format rule further stipulates that since the decoding capability information is included in a NAL unit, the decoding capability information does not include a first syntax element indicating an identifier of the decoding capability information.

33. The non-transitory computer-readable recording medium according to claim 32, wherein The first format rule further stipulates that since the decoding capability information is included in the NAL unit, a sequence parameter set (SPS) does not reference the decoding capability information by including a second syntax element, the second syntax element indicating the identifier of the decoding capability information referenced by the SPS.

34. A method for storing a bitstream of a video, comprising: generating the bitstream of the video, and storing the bitstream in a non-transitory computer-readable recording medium, wherein the bitstream complies with a first format rule, wherein the first format rule stipulates that each of a plurality of network abstraction layer (NAL) units related to decoding parameters indicating decoding capability information in the bitstream has the same content; wherein the first format rule stipulates that a NAL unit related to decoding parameters indicating decoding capability information is in a first access unit (AU) of the bitstream, wherein the first AU is located at the beginning of the bitstream; and The first format rule further stipulates that a plurality of profile, layer and level (PTL) syntax structures are included in the original byte sequence payload of the NAL unit including the decoding capability information.

35. A method of storing a bitstream representing a video to a computer-readable recording medium, comprising: Generating a bitstream from a video according to the method of any one of claims 7 to 24; as well as The bit stream is stored in the computer-readable recording medium.

36. A video processing device comprising a processor, wherein the processor is configured to implement the method according to any one of claims 7 to 24.

37. A computer readable medium having stored thereon instructions which, when executed, cause a processor to perform the method of any one of claims 7 to 24.

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