Delta coding for various syntax elements and quantization parameters inference in dynamic mesh coding

Abstract

A mechanism for processing video data is disclosed. The mechanism includes determining that a supplemental enhancement information (SEI) message is included in a bitstream, in which the SEI message carries danmaku information. A conversion is performed between a visual media data and the bitstream based on the SEI message carrying danmaku information.

Description

Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)Delta Coding For Various Syntax Elements And Quantization Parameters Inference In Dynamic Mesh Coding CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the priority to and benefits of U.S. Provisional Patent Application No. 63 / 708,631 filed on October 17, 2024, and U.S. Provisional Patent Application No. 63 / 773,856 filed on March 18, 2025, both of which are herein incorporated by reference in their entireties.TECHNICAL FIELD

[0002] The present disclosure relates to generation, storage, and consumption of digital audio video media information in a file format.BACKGROUND

[0003] Digital video accounts for the largest bandwidth used on 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 usage is likely to continue to grow.SUMMARY

[0004] A first aspect relates to a method for processing video data comprising: determining that a dedicated supplemental enhancement information (SEI) message is included in a bitstream, wherein the dedicated SEI message comprises a danmaku information SEI message carrying danmaku information; and performing a conversion betw een a visual media data and the bitstream based on the damnaku information SEI message.

[0005] A second aspect relates to an apparatus for processing video data comprising: a processor; and a non- transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to perform any of the preceding aspects.

[0006] A third aspect relates to non-transitory computer readable medium comprising a computer program product for use by a video coding device, the computer program product comprising computer executable instructions stored on the non-transitory computer readable medium such that when executed by a processor cause the video coding device to perform the method of any of the preceding aspects.

[0007] A fourth aspect relates to a non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises: detennining that a dedicated supplemental enhancement information (SEI) message is included in a bitstream, wherein the dedicated SEI message comprises a danmaku information SEI message carrying damnaku information; and generating a bitstream based on the determination.

[0008] A fifth aspect relates to a method for storing bitstream of a video comprising: determining that a dedicated supplemental enhancement information (SEI) message is included in a bitstream, wherein the dedicated SEI message comprises a danmaku information SEI message carty ing damnaku information; generating a bitstream based on the determination; and storing the bitstream in a non-transitory computer-readable recording medium.

[0009] A sixth aspect relates to a method, apparatus, or system described in the present disclosure.

[0010] For the purpose of clarity, any one of the foregoing embodiments may be combined with any one or more of the other foregoing embodiments to create a new embodiment within the scope of the present disclosure.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)

[0011] These and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in comiection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.

[0013] FIG. 1 is a block diagram showing an example video processing system.

[0014] FIG. 2 is a block diagram of an example video processing apparatus.

[0015] FIG. 3 is a flow chart for an example method of video processing.

[0016] FIG. 4 is a block diagram that illustrates an example video coding system.

[0017] FIG. 5 is a block diagram that illustrates an example encoder.

[0018] FIG. 6 is a block diagram that illustrates an example decoder.

[0019] FIG. 7 is a schematic diagram of an example encoder.DETAILED DESCRIPTION

[0020] It should be understood at the outset that although an illustrative implementation of one or more embodiments are provided below7, the disclosed systems and / or methods may be implemented using any number of techniques, whether currently known or yet to be developed. The disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, including the exemplary designs and implementations illustrated and described herein, but may be modified within the scope of the appended claims along with their full scope of equivalents.1. SUMMARY

[0021] This disclosure is related to image / video coding technologies. Specifically, it is related to carrying danmaku information in a video bitstream. The ideas may be applied individually or in various combinations, for video bitstreams coded by any codec, e.g., the versatile video coding (WC) standard and / or the versatile SEI messages for coded video bitstreams (VSEI) standard.2. ABBREVIATIONSAPS Adaptation Parameter SetAU Access UnitCLVS Coded Layer Video SequenceCLVSS Coded Layer Video Sequence StartCRC Cyclic Redundancy CheckCVS Coded Video SequenceFIR Finite Impulse Response1RAP Intra Random Access PointNAL Network Abstraction LayerNNPF neural-netw ork post-processing filterAtty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)NNPFA neural-network post-filter activationNNPFC neural-network post-filter characteristics PPS Picture Parameter Set PU Picture UnitRASL Random Access Skipped LeadingSEI Supplemental Enhancement Information STS A Step-wise Temporal Sublayer Access URI uniform resource identifierVCL Video Coding LayerVSEI versatile supplemental enhancement information (Rec. ITU-T H.274 | ISO / IEC 23002-7) VUI Video Usability InformationWC versatile video coding (Rec. ITU-T H.266 | ISO / IEC 23090-3)3. BACKGROUND3.1. Damnaku

[0022] Damnaku (or danmu) is a subtitle system in online video platforms that originates from Japan and was popularized in Mainland China. Such system allows users to post moving comments onto a playing video that are synchronized to the video timeline. The comments are typically presented as "shooting" across the screen, resembling a barrage.

[0023] In an online video platform, one user can add a damnaku, similar as a comment, to a video, with options of different colours, different positions, etc. When another user watches the video, the accompany ing danmakus from other users can be displayed, usually overlayed with the video to enhance the video's social interaction.3.2. Video coding standards

[0024] Video coding standards have evolved primarily through the development of the well-known International Telecommunication Union - Telecommunication Standardization Sector (ITU-T) and International Organization for Standardization (ISO)ZIntemational Electrotechnical Commission (IEC) standards. The ITU-T produced H.261 and H.263, ISO / IEC produced Moving Picture Experts Group (MPEG)-1 and MPEG-4 Visual, and the two organizations jointly produced the H.262 / MPEG-2 Video and H.264 / MPEG-4 Advanced Video Coding (AVC) and H.265 / HEVC [1] standards. Since H.262, the video coding standards are based on the hybrid video coding structure wherein temporal prediction plus transform coding are utilized. To explore the future video coding technologies beyond HEVC, the Joint Video Exploration Team (JVET) was founded by Video Coding Experts Group (VCEG) and MPEG jointly in 2015. Since then, many new methods have been adopted by JVET and put into the reference software named Joint Exploration Model (JEM) [2], The JVET was later renamed to be the Joint Video Experts Team (JVET) when the Versatile Video Coding (WC) project officially started. WC [3] is the new coding standard, targeting at 50% bitrate reduction as compared to HEVC, that has been finalized by the JVET at its 19th meeting ended on July 1, 2020.

[0025] The Versatile Video Coding (WC) standard (ITU-T H.266 | ISO / IEC 23090-3) [3] and the associated Versatile Supplemental Enhancement Information for coded video bitstreams (VSEI) standard (ITU-T H.274 | ISO / IECAtty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)23002-7) [4] have been designed for use in a maximally broad range of applications, including both the traditional uses such as television broadcast, video conferencing, or playback from storage media, and also newer and more advanced use cases such as adaptive bitrate streaming, video region extraction, composition and merging of content from multiple coded video bitstreams, multiview video, scalable layered coding, and viewport-adaptive 360° immersive media.

[0026] The Essential Video Coding (EVC) standard (ISO / IEC 23094-1) is another video coding standard that has recently been developed by MPEG.3.3. SEI messages in general and in WC and VSEI

[0027] SEI messages assist in processes related to decoding, display or other purposes. However, SEI messages are not required for constructing the luma or chroma samples by the decoding process. Conforming decoders are not required to process this information for output order conformance. Some SEI messages are required for checking bitstream conformance and for output timing decoder conformance. Other SEI messages are not required for check bitstream conformance.

[0028] Annex D of WC specifies syntax and semantics for SEI message payloads for some SEI messages, and specifies the use of the SEI messages and VUI parameters for w hich the syntax and semantics are specified in ITU-T H.274 | ISO / IEC 23002-7 (VSEI).

[0029] JVET is developing the 4th version of VSEI standard, for which the latest draft is [4], Another document [5], specifies the technologies under consideration for future extensions of VSEI.3.4. Text description information SEI

[0030] In the latest draft of additional SEI messages for VSEI version 4 [4], an SEI, named text description information SEI, is specified to let some text information be carried in a video bitstream. Its syntax and semantics are described below.8.35 Text description information SEI message8.35.1 Text description information SEI message syntaxAtty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)8.35.2 Text description information SEI message semanticsThe text description information SEI message provides text description about one or more pictures. txt_descr_purpose indicates the purpose of the text description SEI as specified in Table xx. The value of text_descr_purpose shall be in the range of 0 to 5, inclusive. Values in the range of 6 to 255. inclusive, for text_descr_purpose are reserved for future use by ITU-T | ISO / IEC and shall not be present in bitstreams conforming to this version of this Specification. Decoders conforming to this version of this Specification shall allow any value of text deser purpose in the range of 0 to 255, inclusive.Table xx - Definition of txt_descr_purposetxt cancel flag equal to 1 indicates that the text description information SEI message cancels the persistence of any previous text description information SEI message with the same txt_descr_purpose in output order that applies to the current layer, txt cancel flag equal to 0 indicates that text description information follows. txt dcscr id indicates the identifier value of this text description information SEI message. The value of txt dcscr id shall be in the range of 1 to 16383, inclusive. Value 0 is reserved. Text description SEI messages with different values for txt_descr_purpose use separate values spaces for txt dcscr id. txt id cancel flag equal to 1 indicates that the text description information SEI message cancels the persistence of any previous text description information SEI message with the same txt dcscr id and txt_descr_purpose values as those in the current SEI in output order that applies to the current layer, txt id cancel flag equal to 0 indicates that text description information syntax elements (txt persistence flag, txt num strings minus 1, txt deser string lang[ i ]. txt_descr_string[ i ]) follow. txt_persistence_flag specifies the persistence of the text information description SEI message for the current layer.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W) txt_persistence flag equal to 0 specifies that the text description information applies to the current decoded picture only. txt_persistence_flag equal to 1 specifies that the text description information SEI message applies to the current decoded picture and persists for all subsequent pictures of the current layer in output order until one or more of the following conditions are true:- A new CLVS of the current layer begins.- The bitstream ends.- A picture in the current layer in an AU associated with a text description information SEI message with the same txt descr id is output that follows the current picture in output order. txt num strings minusl plus 1 indicates the number of entries for txt_dcscr_string_lang[ i ] and txt_dcscr_string[ i ] that follow. txt_descr_string_lang[ i ] specifies the language of the txt_descr_string[ i ]. The language of the txt_descr_string[ i ] shall be given by a language tag as defined by IETF RFC 5646. The length of txt_descr_string_lang[ i ] corresponding to the stringLength variable specified in clause 6.3 for the st(v) parsing process shall be in the range of 0 to 49 bytes, inclusive.The value of txt descr string lang [ m ] shall not be equal to the value of txt descr string lang [ n 1 when m is not equal to n, for any values of m and n in the range from 0 to txt num strings minusl, inclusive. txt_descr_string[ i ] specifies i-th text description information string whose value is interpreted as specified by the txt_descr_purpose.When txt_descr_purpose is equal to 0, the interpretation of what information is conveyed in the txt deser string is application-defined.When txt_descr_purpose is equal to 1, the txt_descr_string[ i ] specifies copyright information that pertains to the picture(s) in the persistence scope of this SEI message.When txt_dcscr_purposc is equal to 2, the txt_dcscr_string[ i ] specifics, when not a null string, Al marking information that pertains to the picture(s) within the persistence scope of this SEI message.NOTE: When txt_descr_purpose is equal to 2 the string can contain information about machine-leaming-based processing, intended use of the decoded pictures, or other aspects relevant to the associated pictures.When txt_descr_purpose is equal to 3, the txt_descr_string[ i ] specifies a general text label description that pertains to the picture(s) in the persistence scope of this SEI message.When txt descr_purpose is equal to 4, the txt descr string [ i 1 shall specify content advisory rating information conforming to US and Canadian Rating Region Tables (RRT) as defined by CTA-766-D that pertains to the picture(s) in the persistence scope of this SEI message.When txt_descr_purpose is equal to 5, txt_descr_string[ i ] shall contain a tag URI with syntax and semantics as specified in IETF RFC 4151 identifying the CLVS.4. PROBLEMAlthough danmaku has been widely used in lots of video platforms, there lacks a mechanism to carry danmaku information in a coded video bitstream in a standard-compliant manner.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)5. SOLUTIONS TO THE PROBLEMTo address the above problem, methods as summarized below are disclosed. The solutions should be considered as examples to explain the general concepts and should not be interpreted in a narrow way. Furthermore, these solutions can be applied individually or combined in any manner.1 ) A dedicated SEI message, e.g. , named danmaku information SEI message, is specified to support carrying damnaku information in a video bitstream. a. Alternatively, in one example, danmaku information may be supported by extending another SEI message, e.g., the text description information SEI message, by adding a new purpose for danmaku and one or more syntax elements to indicate related information for danmaku. b. Alternatively, in one example, danmaku information may be supported in the system level, c.g. timed text in ISO base media format by adding a new tag for damnaku and one or more sy ntax elements to indicate related information for danmaku. c. In one example, a syntax element (e.g., a cancelation flag) may be specified to cancel a previous SEI message of the same type (e.g., the danmaku information SEI). i. In one example, when the cancelation flag is equal to 1 , every danmaku with start time before the output time of the current picture, i.e.. the picture associated with the current SEI message, is cancelled. ii. Alternatively', when the cancelation flag is equal to 1, every danmaku with end time before the output time of the current picture is cancelled. d. In one example, the danmaku information SEI message is alloyved to be identified in a SEI processing order (SPO) SEI message. i. In one example, the SEI payloadType value of the danmaku information message is included in the list SeiProcessingOrderSeiList but is not included in the list SpoProcessSeiList. ii. In one example, the SEI payloadType value of the danmaku information message is included in both the list SeiProcessingOrderSeiList and the list SpoProcessSeiList. e. In one example, it is specified that the danmaku information SEI message persists for the current picture (i.e., the picture associated with the damnaku information SEI message) until the next picture in output order that is associated yvith another damnaku information SEI message or the end of the CLVS, whichever is earlier. i. Alternatively, the persistence scope of the SEI message is specified to be the CLVS containing the SEI message. ii. Alternatively', the persistence scope of the SEI message is specified to be the CVS containing the SEI message.2) One or more syntax elements may be specified to indicate the number of danmaku and / or the language of the danmaku in an SEI message. a. In one example, one syntax element may be signalled to specify the number of languages or the number of languages minus 1.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W) i. In one example, the syntax element is coded in u(N), where N is a positive integer. ii. In one example, the syntax element is coded in ue(v) in the range of 0 to N, where N is a positive integer.1. In one example, N is equal to 2K- 1, K is equal to 2, 3, 4, 5, 6, 7, 8, 9 or 10. b. In one example, one syntax element may be signalled to specify the number of danmakus or the number of danmakus minus 1. i. In one example, the syntax element is coded in u(N), where N is a positive integer. ii. In one example, the syntax element is coded in ue(v) in the range of 0 to N, where N is a positive integer.1. In one example, N is equal to 2K- 1, K is equal to 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24.2. In one example, N is equal to 212- 2.3) For a damnaku, in one example, one or more syntax elements may be specified to indicate the daimiaku's content. a. In one example, a danmaku's content is specified by a text string coded in st(v).4) For a damnaku, in one example, one or more syntax elements may be specified to indicate the danmaku's start time, or time to enter the display. a. In one example, a picture order count (POC) difference value may be specified to indicate a danmaku's start time relative to the POC value of the current picture. i. In one example, the POC difference value may be signalled using a ue(v)-coded syntax element, for which the value is in the range of 0 to N, inclusive, where N is a positive integer.1. In one example, N is equal to 2K- 1, K is equal to 8, 10, 12, 14, 16, 20, or 24. ii. In one example, the POC difference value may be signalled using a u(N)-coded syntax element, where N is 8, 10, 12, 14, 16, 20, or 24.5) For a damnaku, in one example, one or more syntax elements may be specified to indicate the danmaku's duration, or time to exit the display. a. In one example, a POC difference value may be specified to indicate a daimiaku's end time relative to the start time. i. In one example, the POC difference value may be signalled using a ue(v)-coded syntax element, for which the value is in the range of 0 to N, inclusive, where N is a positive integer.1. In one example, N is equal to 2K- 1, K is equal to 8. 10, 12, 14. 16, 20, or 24. ii. In one example, the POC difference value may be signalled using a u(N)-coded syntax element, where N is 8, 10, 12, 14, 16, 20, or 24. b. In one example, a POC difference value may be specified to indicate a danmaku's end time relative to the POC value of the current picture. i. In one example, the POC difference value may be signalled using a ue(v)-coded sy ntax element, for which the value is in the range of 0 to N, inclusive, where N is a positive integer.1. In one example, N is equal to 2K- 1, K is equal to 8, 10, 12, 14, 16, 20, or 24.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W) ii. In one example, the POC difference value may be signalled using a u(N)-coded syntax element, where N is 8, 10, 12, 14, 16, 20, or 24. c. In one example, a fixed duration value, may be signalled in the SEI message. i. In one example, whether to signal the fixed duration value depends on a flag. ii.In one example, when the fixed duration value is not present, its value is inferred to be equal to N.1. In one example, N is equal to 60. d. In one example, for each danmaku, a flag is signalled to indicate whether the danmaku has a fixed duration. i. In one example, when the flag indicates the danmaku has a fixed duration, its duration is set equal to a fixed duration value indicated in the SEI message.1. In one example, when the flag indicates the danmaku has a fixed duration, the syntax element(s) to indicate the danmaku's end time is not signalled.2. In one example, when the flag indicates the damnaku has a fixed duration, its end time is inferred to be Min(start time + the fixed duration value, maximum allowable end time).6) For a danmaku or a set of danmaku, in one example, one or more syntax elements may be specified to indicate the danmaku's relative position information in the display. a. In one example, the position information may include top and / or bottom and / or scrolling from right to left and / or scrolling from left to right. b. In one example, the position information may indicate the exact position (e.g., relative to the video being displayed, e.g., the exact position of the upper-left comer of the danmaku relative to the upperleft comer of the video). c. In one example, the relative position indicates the preferred display’ method of the danmaku. i. In one example, the display- method may be determined by the client, i.e. displayer when display the damnaku. ii. In one example, the display method may be adjusted by the client, i.e. displayer considering the preferred display method yvhen display the danmaku. iii. In one example, the client, i.e. displayer can choose not to display the danmaku.7) For a danmaku or a set of danmaku, in one example, one or more syntax elements may be specified to indicate the danmaku's colour, which may or may not including an alpha channel. a. In one example, the whole danmaku has the same colour. b. In one example, each character or word of the danmaku may have a different colour. c. In one example, a syntax element is specified to indicate the colour index of the danmaku. i. In one example, the syntax element specifies the index to a colour table.1. In one example, the colour table may contain one or more pre-defined colours.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)2. In one example, the colour table may contain one or more colours signalled in the SEI message.3. In one example, the colour table may contain one or more colours that can be updated during decoding. ii. In one example, a special index may be used to indicate the colour information is directly signalled as an RGB or YUV value.8) For a danmaku or a set of danmaku, in one example, one or more syntax elements may be specified to indicate the danmaku's language information. a. In one example, the language information may be specified by a text string coded in st(v) to indicate the language tag as specified by IETF RFC 5646. b. In one example, a language index may be specified to indicate the index to a language table. i. In one example, the language table may contain one or more pre-defined languages. ii. In one example, the language table may contain one or more languages signalled in the SEI message. iii. In one example, the language table may contain one or more languages that can be updated during decoding.9) For a danmaku or a set of danmaku, in one example, one or more syntax elements may be specified to indicate the danmaku's source. a. In one example, one or more syntax elements may be specified to indicate the user ID from which the danmaku is generated.10) For a danmaku, in one example, one or more syntax elements may be specified to indicate the danmaku's ID.11) For a danmaku, in one example, one or more syntax elements may be specified to indicate the danmaku's importance. a. In one example, the client may decide to display or not display a danmaku based on its importance value. b. In one example, when two danmakus are overlapped during display, the client, i.e. displayer, may use importance value to decide which one danmaku is displayed in the overlapped display area.12) For a danmaku, in one example, one or more syntax elements may be specified to indicate its relationship to another danmaku. a. In one example, one or more syntax elements may be specified to indicate whether the current danmaku is a reply to another danmaku, and if yes, which danmaku. b. In one example, one or more syntax elements may be specified to indicate whether the current danmaku belongs to a certain group, and if yes, which group.13) For a danmaku or a set of danmaku, in one example, one or more syntax elements may' be specified to indicate a danmaku's font type and / or font size. a. In one example, the font type and / or font size indicated are preferred parameters.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W) i. In one example, those parameters may be overwritten by the client, i.e. displayer when display the danmaku. ii. In one example, those parameters may be adjusted by the client, i.e. displayer when display the danmaku.14) To use the related SEI message, in one example, in the interface text of the SEI message described in the WC specification, a variable is set equal to the POC value of the current picture. a. In one example, in the WC interface text of the SEI message, it is specified that the variable CurrPoc is set equal to PicOrderCntVal of the current picture, i.e. the picture in the same PU that contains the danmu information SEI message.6. EMBODIMENTS

[0031] Below are some example embodiments for the invention aspects summarized above in Section 5.

[0032] Unless further specified, most relevant parts that have been added or modified are highlighted in double braces (i.e., { {a} } indicates that ‘a’ is added), and some of the deleted parts are highlighted in triple brackets (i.e., [[[a]]] indicates that 'a’ is deleted). There may be some other changes that are editorial in nature and thus not highlighted.6.1. Embodiment !

[0033] This embodiment covers the solution items 1-7.

[0034] The following texts are added to the draft VSEI document based on JVET-AI2032-v3.docx8.46 Danmaku information SEI message8.46.1 Danmaku information SEI message syntaxAtty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)8.46.2 Danmaku information SEI message semanticsThe danmaku information (DI) SEI message provides danmaku information.The DI SEI message persists for the current picture until the next picture in output order that is associated with another DI SEI message or the end of the CLVS, whichever is earlier. di cancel flag equal to 1 indicates that the SEI message cancels the persistence of any previous danmaku SEI message associated with a picture earlier than the current picture in output order, di cancel flag equal to 0 indicates that danmaku information follows. di num danmaku minusl plus 1 specifies the number of danmaku in this SEI message. The value of di num danmaku minusl shall be in the range of 0 to 232- 2. inclusive. di num languages minusl plus 1 specifies the number of languages for the danmaku in this SEI message. The value of di num languages minusl shall be in the range of 0 to 63, inclusive. di bitl equal to zero shall be equal to 0. di_language[ i ] contains a language tag as specified by IETF RFC 5646 followed by a null termination byte equal to 0x00. The length of the di_language[ i ] syntax element shall be less than or equal to 255 bytes, not including the null termination byte. di_position[ i ] specifies the suggested display method for the i-th danmaku. The list of display methods is shown in the following table.Table x- Mapping of di_position[ i ] to the display methodAtty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W) di_colour_idc[ i ] specifies the colour index for the i-th danmaku. The rgb colour value for index from 0 to 14, inclusive, is shown in the following table.Table x- Mapping of di colour idc to the danmaku colourdi_colour_rgb[ i ] specifies the rgb colour for the i-th danmaku when di_colour_idc[ i ] is equal to 15. The format of the RGB value is as Oxrrggbb, i.e., the 8 MSBs represent the red colour component, the 8 LSBs represent the blue colour component, and the 8 bits in the middle represent the green colour component. di_start_delta_poc[ i ] plus the POC value of the current picture specifies the value of the variable startPoc[ i ]. If there is a picture picA in the CLVS with POC equal to startPoc[ i ], the display of i-th danmaku should start from the picture picA. Otherwise (there is no picture in the CLVS with POC equal to startPoc[ i ]), the display of the i-th danmaku should start from the picture in the CLVS with the smallest POC value among all pictures with POC greater than startPoc[ i ]. The value of di_start_delta_poc[ i ] shall be in the range of 0 to 65535, inclusive. di_end_delta_poc[ i ] plus di_start_delta_poc[ i ] plus the POC value of the current picture specifies the value of the variable endPoc[ i J. Ifthere is a picture picB in the CLVS with POC equal to cndPoc| i J, the display of the i-th danmaku should end at the picture picB. Otherwise (there is no picture in the CLVS with POC equal to endPocf i ]), the display of the i-th danmaku should end at the picture in the CLVS with the greatest POC value among all pictures with POC less than endPoc[ i ]. The value of di_end_delta_poc[ i ] shall be in the range of 0 to 65535, inclusive. di_lang_idx[ i ] specifies that language of the i-th danmaku is indicated by di_language[ di_lang_idx[ i ] ]. When not present, di_lang_idx[ i ] is inferred to be 0. di_bit2_equal_to_zero shall be equal to 0.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W) di_text[ i ] specifies the text for the i-th danmaku.6.2. Embodiment 2This embodiment covers the invention items l.a, 2-7.The following text changes are based on the document JVET-AI2006-v3.docx8.35 Text description information SEI message8.35.1 Text description information SEI message syntax8.35.2 Text description information SEI message semanticsThe text description information SEI message provides text description about one or more pictures. txt_descr_purpose indicates the purpose of the text description SEI as specified in Table xx. The value of text_descr_purpose shall be in the range of 0 to 5, inclusive. Values in the range of 6 to 255. inclusive, forAtty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W) text_descr_purpose are reserved for future use by ITU-T | ISO / IEC and shall not be present in bitstreams conforming to this version of this Specification. Decoders conforming to this version of this Specification shall allow any value of text_descr_purpose in the range of 0 to 255, inclusive.Table xx - Definition of txt_descr_purposetxt descr stringf i ] specifies i-th text description information string whose value is interpreted as specified by the txt_descr_purpose.When txt_descr_purpose is equal to 0, the interpretation of what information is conveyed in the txt descr string is application-defined.When txt_descr_purpose is equal to 1, the txt descr stringf i ] specifies copyright information that pertains to the picture(s) in the persistence scope of this SEI message.When txt_descr_purpose is equal to 2, the txt_descr_string[ i ] specifies, when not a null string, Al marking information that pertains to the picture(s) within the persistence scope of this SEI message.NOTE: When txt_descr_purpose is equal to 2 the string can contain information about machine-leaming-based processing, intended use of the decoded pictures, or other aspects relevant to the associated pictures.When txt_descr_purpose is equal to 3, the txt descr strin f i ] specifies a general text label description that pertains to the picture(s) in the persistence scope of this SEI message.When txt_descr_purpose is equal to 4, the txt descr stringf i ] shall specify content advisory’ rating information conforming to US and Canadian Rating Region Tables (RRT) as defined by’ CTA-766-D that pertains to the picturc(s) in the persistence scope of this SEI message.When txt_descr_purpose is equal to 5, txt descr stringf i ] shall contain a tag URI with syntax and semantics as specified in IETF RFC 4151 identifying the CLVS.{ {When txt_descr_purpose is equal to 6, the txt descr stringf i ] specifies a damnaku text that pertains to the picture(s) in the persistence scope of this SEI message.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W) txt_position[ i ] specifies the suggested display method for the i-th danmaku. The list of display methods is shown in the following table.Table x- Mapping of txt_position[ i ] to the display methodtxt_colour_idc| i ] specifies the colour index for the i-th danmaku. The rgb colour value for index from 0 to 14, inclusive, is shown in the following table.Table x- Mapping of txt colour idc to the danmaku colourtxt_colour_rgb[ i ] specifies the rgb colour for the i-th danmaku when di_colour_idc[ i ] is equal to 15. The format of the RGB value is as Oxrrggbb, i.e., the 8 MSBs represent the red colour component, the 8 LSBs represent the blue colour component, and the 8 bits in the middle represent the green colour component.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W) txt_start_delta_poc[ i ] plus the POC value of the current picture specifies the value of the variable startPoc[ i ]. If there is a picture picA in the CLVS with POC equal to startPocf i ], the display of i-th danmaku should start from the picture picA. Otherw ise (there is no picture in the CLVS with POC equal to startPoc[ i ]), the display of the i-th danmaku should start from the picture in the CLVS with the smallest POC value among all pictures with POC greater than startPoc[ i ]. txt_end_delta_poc[ i ] plus txt_start_delta_poc[ i ] plus the POC value of the current picture specifies the value of the variable endPoc[ i ]. Ifthere is a picture picB in the CLVS with POC equal to endPoc[ i ], the display ofthe i-th danmaku should end at the picture picB. Otherwise (there is no picture in the CLVS with POC equal to endPoc[ i ]), the display of the i-th danmaku should end at the picture in the CLVS with the greatest POC value among all pictures with POC less than cndPoc[ i ]. } }6.3 Embodiment 3This embodiment covers the items La, 2-7, 14, 14. a.The following texts are added to the draft WC document based on JVET-AK2005-v2.docx [6],D.12.2x Use ofthe danmu information SEI messageFor purposes of interpretation of the danmu information SEI, the variable CurrPoc is set equal to PicOrderCntVal of the current picture, as described in clause 8.3.1 of the VVC spec. The current picture is the picture in the same PU that contains the danmu information SEI message.The following texts are added to the draft VSEI document based on JVET-AI2032-v3.docx8.46 Danmu information SEI message8.46.1 Danmu information SEI message syntaxAtty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)8.46.2 Danmu information SEI message semanticsThe danmu information (DI) SEI message provides danmu information.The DI SEI message persists for the current picture until the next picture in output order that is associated with another DI SEI message or the end of the CL VS, whichever is earlier. di cancel flag equal to 1 indicates that the SEI message cancels the persistence of any previous danmu SEI message associated with a picture earlier than the current picture in output order, di cancel flag equal to 0 indicates that danmu information follows. di num danmu minusl plus 1 specifies the number of danmu in this SEI message. The value of di num danmu minusl shall be in the range of 0 to 232- 2, inclusive. di num languages minusl plus 1 specifies the number of languages for the danmu in this SEI message. The value of di num languages minusl shall be in the range of 0 to 63, inclusive. di_fixed_duration_param_present_flag equal to 1 indicates that the syntax element di fixed duration is present in the DI SEI message. di_fixed_duration_param_present_flag equal to 0 indicates that the syntax element di fixed duration is not present in the DI SEI message. di fixed duration specifies the duration value in POC units of the i-th danmu with di_fixed_duration_flag[ i ] equal to 1. When not present, the value of di fixed duration is inferred to be equal to 60. di bitl equal to zero shall be equal to 0. di_language[ i ] contains a language tag as specified by IETF RFC 5646 followed by a null termination byte equal to 0x00. The length of the di_language[ i ] syntax element shall be less than or equal to 255 bytes, not including the null termination byte.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W) di_display_type_idc[ i ] specifies the suggested display method for the i-th danmu. The list of display methods is shown in the following table.Table x- Mapping of di_display_type_idc[ i ] to the display methoddi_colour_idc[ i ] specifies the colour index for the i-th danmu. The rgb colour value for index from 0 to 14, inclusive, is shown in the following table.Table x- Mapping of di colour idc to the danmu colourAtty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)di_colour_rgb[ i ] specifies the rgb colour for the i-th danmu when di_colour_idc[ i is equal to 15. The format of the RGB value is as Oxrrggbb, i.e., the 8 MSBs represent the red colour component, the 8 LSBs represent the blue colour component, and the 8 bits in the middle represent the green colour component. di_start_dclta_poc[ i ] plus CurrPoc specifics the value of the variable startPoc[ i ]. If there is a picture pic A in the CLVS with POC equal to startPoc[ i ], the display- of i-th danmu should start from the picture picA. Otherwise (there is no picture in the CLVS with POC equal to startPoc[ i ]), the display of the i-th danmu should start from the picture in the CLVS with the smallest POC value among all pictures with POC greater than startPoc[ i ]. The value of di_start_delta_poc[ i ] shall be in the range of 0 to 65535, inclusive. di_fixed_duration_flag[ i ] equal to 1 indicates that the syntax element di_end_delta_poc[ i ] is not present in the DI SEI message, di fixed duration flag [ i ] equal to 0 indicates that the syntax element di end delta_poc[ i ] is present in the DI SEI message. di_end_delta_poc[ i ] plus di_start_delta_poc[ i ] plus the POC value of the current picture specifies the value of the variable endPoc[ i ]. If there is a picture picB in the CLVS with POC equal to endPoc[ i ], the display of the i-th danmu should end at the picture picB. Otherwise (there is no picture in the CLVS with POC equal to endPoc[ i ]), the display of the i-th danmu should end at the picture in the CLVS with the greatest POC value among all pictures with POC less than endPoc[ i ]. The value of di_end_delta_poc[ i ] shall be in the range of 0 to 65535, inclusive. When not present, the value of di_end_delta_poc[ i ] is inferred to be equal to Min( di_end_delta_poc[ i ] + di fixed duration, 65535). di_lang_idx[ i ] specifies that language of the i-th danmu is indicated by di_language[ di_lang_idx[ i ] ]. When not present, di_lang_idx[ i ] is inferred to be 0. di_bit2_equal_to_zero shall be equal to 0. di_text[ i ] specifies the text for the i-th danmu.7. REFERENCES

[0035]

[0001] ITU-T and ISO / IEC, “High efficiency video coding,” Rec. ITU-T H.265 | ISO / IEC 23008-2 (in force edition).

[0036] [2] Rcc. ITU-T H.266 | ISO / IEC 23090-3, “Versatile Video Coding,” 2023.

[0037] [3] Rec. ITU-T Rec. H.274 | ISO / IEC 23002-7, “Versatile Supplemental Enhancement InformationMessages for Coded Video Bitstreams,” 2023.

[0038] [4] J. Boyce, J. Chen, S. Deshpande, M. M. Hannuksela, S. McCarthy, G. J. Sullivan, H. Tan, Y.-K. Wang(editors), “Additional SEI messages for VSEI version 4 (Draft 3)," JVET output document JVET-AI2006, publicly available online herein: https: / / ivet-cxperts.org / doc_cnd_iiscr / docimients / 35_Sapporo / wgl lZJVET-AI2006-v3.zipAtty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)

[0039] [5] S. McCarthy, J. Boyce, J. Chen, S. Deshpande, M. M. Hannuksela, H. Tan, Y.-K. Wang (editors).“Technologies under consideration for future extensions of VSEI (version 5),’’ JVET output document JVET-AI2032, publicly available online herein: https: / / jvet-experts.org / doc_end_user / documents / 35_Sapporo / wgl l / JVET-AI2032- v3.zip

[0040] [6] G. J. Sullivan, B. Brass, M. M. Hannuksela, Y.-K. Wang (editors), “Additions and corrections forWC version 4 (Draft 11),” JVET output document JVET-AK2005-v2, publicly available online herein: https: / / www.jvet-experts.org / doc_end_user / documents / 37_Geneva / wgl l / JVET-AK2005-v2.zip.

[0041] FIG. 1 is a block diagram showing an example video processing system 4000 in which various techniques disclosed herein may be implemented. Various implementations may include some or all of the components of the system 4000. The system 4000 may include input 4002 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 in a compressed or encoded format. The input 4002 may represent a network interface, a peripheral bus interface, or a storage interface. Examples of network interface include wired interfaces such as Ethernet, passive optical network (PON), etc. and wireless interfaces such as wireless fidelity (Wi-Fi) or cellular interfaces.

[0042] The system 4000 may include a coding component 4004 that may implement the various coding or encoding methods described in the present disclosure. The coding component 4004 max' reduce the average bitrate of video from the input 4002 to the output of the coding component 4004 to produce a coded representation of the video. The coding techniques are therefore sometimes called video compression or video transcoding techniques. The output of the coding component 4004 may be either stored, or transmitted via a communication connected, as represented by the component 4006. The stored or communicated bitstream (or coded) representation of the video received at the input 4002 max- be used by a component 4008 for generating pixel values or displayable video that is sent to a display interface 4010. The process of generating user- viewable video from the bitstream representation is sometimes called video decompression. Furthermore, while certain video processing operations are referred to as “coding” operations or tools, it xvill be appreciated that the coding tools or operations are used at an encoder and corresponding decoding tools or operations that reverse the results of the coding will be performed by a decoder.

[0043] Examples of a peripheral bus interface or a display interface may include unix ersal serial bus (USB) or high definition multimedia interface (HDMI) or DisplayPort, and so on. Examples of storage interfaces include serial advanced technology attachment (SATA), peripheral component interconnect (PCI), integrated drive electronics (IDE) interface, and the like. The techniques described in the present disclosure may be embodied in various electronic devices such as mobile phones, laptops, smartphones or other devices that are capable of performing digital data processing and / or video display.

[0044] FIG. 2 is a block diagram of an example video processing apparatus 4100. The apparatus 4100 may be used to implement one or more of the methods described herein. The apparatus 4100 may be embodied in a smartphone, tablet, computer, Internet of Things (loT) receiver, and so on. The apparatus 4100 may include one or more processors 4102, one or more memories 4104 and video processing circuitry 4106. The processor(s) 4102 may be configured to implement one or more methods described in the present disclosure. The memory (memories) 4104 may be used forAtty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W) storing data and code used for implementing the methods and teclmiques described herein. The video processing circuitry 4106 may be used to implement, in hardware circuitry, some techniques described in the present disclosure. In some embodiments, the video processing circuitry 4106 may be at least partly included in the processor 4102, e.g.. a graphics co-processor.

[0045] FIG. 3 is a flowchart for an example method 4200 of video processing. The method 4200 determines that a dedicated supplemental enhancement information (SEI) message is included in a bitstream, wherein the dedicated SEI message comprises a daimiaku information SEI message carrying danmaku information at step 4202. A conversion between a visual media data and a bitstream based on the daimiaku information SEI message at step 4204. The conversion may include encoding at an encoder, decoding at a decoder, or combinations thereof.

[0046] It should be noted that the method 4200 can be implemented in an apparatus for processing video data comprising a processor and a non-transitory memory with instructions thereon, such as video encoder 4400. video decoder 4500, and / or encoder 4600. In such a case, the instructions upon execution by the processor, cause the processor to perform the method 4200. Further, the method 4200 can be performed by a non-transitory computer readable medium comprising a computer program product for use by a video coding device. The computer program product comprises computer executable instructions stored on the non-transitory computer readable medium such that when executed by a processor cause the video coding device to perform the method 4200.

[0047] FIG. 4 is a block diagram that illustrates an example video coding system 4300 that may utilize the techniques of this disclosure. The video coding system 4300 may include a source device 4310 and a destination device 4320. Source device 4310 generates encoded video data which may be referred to as a video encoding device. Destination device 4320 may decode the encoded video data generated by source device 4310 which may be referred to as a video decoding device.

[0048] Source device 4310 may include a video source 4312, a video encoder 4314, and an input / output (I / O) interface 4316. Video source 4312 may include a source such as a video capture device, an interface to receive video data from a video content provider, and / or a computer graphics system for generating video data, or a combination of such sources. The video data may comprise one or more pictures. Video encoder 4314 encodes the video data from video source 4312 to generate a bitstream. The bitstream may include a sequence of bits that form a coded representation of the video data. The bitstream may include coded pictures and associated data. The coded picture is a coded representation of a picture. The associated data may include sequence parameter sets, picture parameter sets, and other syntax structures. I / O interface 4316 may include a modulator / dcmodulator (modem) and / or a transmitter. The encoded video data may be transmitted directly to destination device 4320 via I / O interface 4316 through network 4330. The encoded video data may also be stored onto a storage medium / server 4340 for access by destination device 4320.

[0049] Destination device 4320 may include an I / O interface 4326, a video decoder 4324. and a display device 4322. I / O interface 4326 may include a receiver and / or a modem. I / O interface 4326 may acquire encoded video data from the source device 4310 or the storage medium / server 4340. Video decoder 4324 may decode the encoded video data. Display device 4322 may display the decoded video data to a user. Display device 4322 may be integrated withAtty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W) the destination device 4320, or may be external to destination device 4320. which can be configured to interface with an external display device.

[0050] Video encoder 4314 and video decoder 4324 may operate according to a video compression standard, such as the High Efficiency Video Coding (HEVC) standard, Versatile Video Coding (WC) standard and other current and / or further standards.

[0051] FIG. 5 is a block diagram illustrating an example of video encoder 4400, which may be video encoder 4314 in the system 4300 illustrated in FIG. 4. Video encoder 4400 may be configured to perform any or all of the teclmiques of this disclosure. The video encoder 4400 includes a plurality of functional components. The techniques described in this disclosure may be shared among the various components of video encoder 4400. In some examples, a processor may be configured to perform any or all of the teclmiques described in this disclosure.

[0052] The functional components of video encoder 4400 may include a partition unit 4401; a prediction unit 4402, which may include a mode select unit 4403, a motion estimation unit 4404, a motion compensation unit 4405, and an intra prediction unit 4406; a residual generation unit 4407; a transform processing unit 4408; a quantization unit 4409; an inverse quantization unit 4410; an inverse transform unit 4411; a reconstruction unit 4412; a buffer 4413; and an entropy encoding unit 4414.

[0053] In other examples, video encoder 4400 may include more, fewer, or different functional components. In an example, prediction unit 4402 may include an intra block copy (IBC) unit. The IBC unit may perform prediction in an IBC mode in which at least one reference picture is a picture where the current video block is located.

[0054] Furthermore, some components, such as motion estimation unit 4404 and motion compensation unit 4405 may be highly integrated, but are represented in the example of video encoder 4400 separately for purposes of explanation.

[0055] Partition unit 4401 may partition a picture into one or more video blocks. Video encoder 4400 and video decoder 4500 may support various video block sizes.

[0056] Mode select unit 4403 may select one of the coding modes, intra or inter, e.g., based on error results, and provide the resulting intra or inter coded block to a residual generation unit 4407 to generate residual block data and to a reconstruction unit 4412 to reconstruct the encoded block for use as a reference picture. In some examples, mode select unit 4403 may select a combination of intra and inter prediction (CIIP) mode in which the prediction is based on an inter prediction signal and an intra prediction signal. Mode select unit 4403 may also select a resolution for a motion vector (e.g., a sub-pixel or integer pixel precision) for the block in the case of inter prediction.

[0057] To perform inter prediction on a current video block, motion estimation unit 4404 may generate motion information for the current video block by comparing one or more reference frames from buffer 4413 to the current video block. Motion compensation unit 4405 may determine a predicted video block for the current video block based on the motion information and decoded samples of pictures from buffer 4413 other than the picture associated with the current video block.

[0058] Motion estimation unit 4404 and motion compensation unit 4405 may perform different operations for a current video block, for example, depending on whether the current video block is in an I slice, a P slice, or a B slice.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)

[0059] In some examples, motion estimation unit 4404 may perform uni-directional prediction for the current video block, and motion estimation unit 4404 may search reference pictures of list 0 or list 1 for a reference video block for the current video block. Motion estimation unit 4404 may then generate a reference index that indicates the reference picture in list 0 or list 1 that contains the reference video block and a motion vector that indicates a spatial displacement betw een the current video block and the reference video block. Motion estimation unit 4404 may output the reference index, a prediction direction indicator, and the motion vector as the motion information of the current video block. Motion compensation unit 4405 may generate the predicted video block of the current block based on the reference video block indicated by the motion information of the current video block.

[0060] In other examples, motion estimation unit 4404 may perfonn bi-directional prediction for the current video block, motion estimation unit 4404 may search the reference pictures in list 0 for a reference video block for the current video block and may also search the reference pictures in list 1 for another reference video block for the current video block. Motion estimation unit 4404 may then generate reference indexes that indicate the reference pictures in list 0 and list 1 containing the reference video blocks and motion vectors that indicate spatial displacements between the reference video blocks and the current video block. Motion estimation unit 4404 may output the reference indexes and the motion vectors of the current video block as the motion information of the current video block. Motion compensation unit 4405 may generate the predicted video block of the current video block based on the reference video blocks indicated by the motion information of the current video block.

[0061] In some examples, motion estimation unit 4404 may’ output a full set of motion information for decoding processing of a decoder. In some examples, motion estimation unit 4404 may not output a full set of motion information for the current video. Rather, motion estimation unit 4404 may signal the motion information of the current video block with reference to the motion information of another video block. For example, motion estimation unit 4404 may detennine that the motion information of the current video block is sufficiently similar to the motion information of a neighboring video block.

[0062] In one example, motion estimation unit 4404 may indicate, in a syntax structure associated with the current video block, a value that indicates to the video decoder 4500 that the current video block has the same motion information as another video block.

[0063] In another example, motion estimation unit 4404 may’ identify’, in a sy ntax structure associated with the current video block, another video block and a motion vector difference (MVD). The motion vector difference indicates a difference between the motion vector of the current video block and the motion vector of the indicated video block. The video decoder 4500 may use the motion vector of the indicated video block and the motion vector difference to detennine the motion vector of the current video block.

[0064] As discussed above, video encoder 4400 may predictively signal the motion vector. Two examples of predictive signaling techniques that may be implemented by video encoder 4400 include advanced motion vector prediction (AMVP) and merge mode signaling.

[0065] Intra prediction unit 4406 may perform intra prediction on the current video block. When intra prediction unit 4406 performs intra prediction on the current video block, intra prediction unit 4406 may’ generate prediction dataAtty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W) 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.

[0066] Residual generation unit 4407 may generate residual data for the current video block by subtracting the predicted video block(s) of the current video block from the current video block. The residual data of the current video block may include residual video blocks that correspond to different sample components of the samples in the current video block.

[0067] In other examples, there may be no residual data for the current video block for the current video block, for example in a skip mode, and residual generation unit 4407 may not perform the subtracting operation.

[0068] Transform processing unit 4408 may generate one or more transform coefficient video blocks for the current video block by applying one or more transforms to a residual video block associated with the current video block.

[0069] After transform processing unit 4408 generates a transform coefficient video block associated with the current video block, quantization unit 4409 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.

[0070] Inverse quantization unit 4410 and inverse transform unit 4411 may apply inverse quantization and inverse transforms to the transform coefficient video block, respectively, to reconstruct a residual video block from the transform coefficient video block. Reconstruction unit 4412 may add the reconstructed residual video block to corresponding samples from one or more predicted video blocks generated by the prediction unit 4402 to produce a reconstructed video block associated with the current block for storage in the buffer 4413.

[0071] After reconstruction unit 4412 reconstructs the video block, the loop filtering operation may be performed to reduce video blocking artifacts in the video block.

[0072] Entropy encoding unit 4414 may receive data from other functional components of the video encoder 4400. When entropy encoding unit 4414 receives the data, entropy encoding unit 4414 may perform one or more entropy encoding operations to generate entropy encoded data and output a bitstream that includes the entropy encoded data.

[0073] FIG. 6 is a block diagram illustrating an example of video decoder 4500 which may be video decoder 4324 in the system 4300 illustrated in FIG. 4. The video decoder 4500 may be configured to perform any or all of the techniques of this disclosure. In the example shown, the video decoder 4500 includes a plurality of functional components. The techniques described in this disclosure may be shared among the various components of the video decoder 4500. In some examples, a processor may be configured to perform any or all of the techniques described in this disclosure.

[0074] In the example shown, video decoder 4500 includes an entropy decoding unit 4501, a motion compensation unit 4502, an intra prediction unit 4503, an inverse quantization unit 4504, an inverse transformation unit 4505, a reconstruction unit 4506, and a buffer 4507. Video decoder 4500 may, in some examples, perform a decoding pass generally reciprocal to the encoding pass described with respect to video encoder 4400.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)

[0075] Entropy decoding unit 4501 may retrieve an encoded bitstream. The encoded bitstream may include entropy coded video data (e.g., encoded blocks of video data). Entropy decoding unit 4501 may decode the entropy coded video data, and from the entropy decoded video data, motion compensation unit 4502 may determine motion information including motion vectors, motion vector precision, reference picture list indexes, and other motion information. Motion compensation unit 4502 may, for example, determine such information by performing the AMVP and merge mode.

[0076] Motion compensation unit 4502 may produce motion compensated blocks, possibly performing interpolation based on interpolation filters. Identifiers for interpolation filters to be used with sub-pixel precision may be included in the syntax elements.

[0077] Motion compensation unit 4502 may use interpolation filters as used by video encoder 4400 during encoding of the video block to calculate interpolated values for sub-integer pixels of a reference block. Motion compensation unit 4502 may determine the interpolation filters used by video encoder 4400 according to received syntax information and use the interpolation filters to produce predictive blocks.

[0078] Motion compensation unit 4502 may use some of the syntax information to determine sizes of blocks used to encode framc(s) and / or slicc(s) of the encoded video sequence, partition information that describes how each macroblock of a picture of the encoded video sequence is partitioned, modes indicating how each partition is encoded, one or more reference frames (and reference frame lists) for each inter coded block, and other information to decode the encoded video sequence.

[0079] Intra prediction unit 4503 may use intra prediction modes for example received in the bitstream to form a prediction block from spatially adjacent blocks. Inverse quantization unit 4504 inverse quantizes, i.e., de-quantizes, the quantized video block coefficients provided in the bitstream and decoded by entropy decoding unit 4501. Inverse transform unit 4505 applies an inverse transform.

[0080] Reconstruction unit 4506 may sum the residual blocks with the corresponding prediction blocks generated by motion compensation unit 4502 or intra prediction unit 4503 to form decoded blocks. If desired, a deblocking filter may also be applied to filter the decoded blocks in order to remove blockiness artifacts. The decoded video blocks are then stored in buffer 4507, which provides reference blocks for subsequent motion compensation / intra prediction and also produces decoded video for presentation on a display device.

[0081] FIG. 7 is a schematic diagram of an example encoder 4600. The encoder 4600 is suitable for implementing the techniques of WC. The encoder 4600 includes three in-loop filters, namely a deblocking filter (DF) 4602, a sample adaptive offset (SAG) 4604, and an adaptive loop filter (ALF) 4606. Unlike the DF 4602, which uses predefined filters, the SAO 4604 and the ALF 4606 utilize the original samples of the current picture to reduce the mean square errors between the original samples and the reconstructed samples by adding an offset and by applying a finite impulse response (FIR) filter, respectively, with coded side information signaling the offsets and filter coefficients. The ALF 4606 is located at the last processing stage of each picture and can be regarded as a tool trying to catch and fix artifacts created by the previous stages.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)

[0082] The encoder 4600 further includes an intra prediction component 4608 and a motion estimation / compensation (ME / MC) component 4610 configured to receive input video. The intra prediction component 4608 is configured to perform intra prediction, while the ME / MC component 4610 is configured to utilize reference pictures obtained from a reference picture buffer 4612 to perform inter prediction. Residual blocks from inter prediction or intra prediction are fed into a transform (T) component 4614 and a quantization (Q) component 4616 to generate quantized residual transform coefficients, which are fed into an entropy coding component 4618. The entropy coding component 4618 entropy codes the prediction results and the quantized transform coefficients and transmits the same toward a video decoder (not shown). Quantization components output from the quantization component 4616 may be fed into an inverse quantization (IQ) components 4620, an inverse transform component 4622, and a reconstruction (REC) component 4624. The REC component 4624 is able to output images to the DF 4602, the SAO 4604, and the ALF 4606 for filtering prior to those images being stored in the reference picture buffer 4612.

[0083] A listing of solutions preferred by some examples is provided next.

[0084] The following solutions show examples of techniques discussed herein.

[0085] 1. A method for processing media data comprising: determining that a dedicated supplemental enhancement information (SEI) message is included in a bitstream, wherein the dedicated SEI message comprises a danmaku information SEI message carrying danmaku information; and performing a conversion between a visual media data and the bitstream based on the damnaku information SEI message.

[0086] 2. The method of claim 1 , further comprising determining that the danmaku information is supported by extending another SEI message by adding a new purpose for danmaku and includes one or more syntax elements to indicate related information for danmaku, wherein the another SEI message is extended using a text description SEI message.

[0087] 3. The method of any of claims 1-2, further comprising determining that the danmaku information is supported in a system level by adding a new tag for danmaku and one or more syntax elements to indicate related information for danmaku, wherein the danmaku information is supported in the system level by timed text in International Organization for Standardization (ISO) base media format.

[0088] 4. The method of any of claims 1-3, wherein a syntax element (e.g.. a cancelation flag) is specified to cancel a previous SEI message of a same type, wherein the syntax element comprises a cancellation flag, and wherein the SEI message of the same type comprises the danmaku information SEI message.

[0089] 5. The method of claim 4, w herein every7danmaku with a start time before an output time of a current picture is cancelled when the cancellation flag is equal to 1, and wherein the current picture is associated with the current SEI message.

[0090] 6. The method of claim 4, wherein every danmaku with an end time before an output time of a current picture is cancelled when the cancellation flag is equal to 1, and wherein the current picture is associated with the current SEI message.

[0091] 7. The method of any of claims 1-6. wherein the danmaku information SEI message is allowed to be identified in a SEI processing order (SPO) SEI message.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)

[0092] 8. The method of any of claims 1 -7, wherein an SEI payloadType value of the danmaku SEI information message is included in a list SeiProcessingOrderSeiList but is not included in the list SpoProcessSeiList.

[0093] 9. The method of any of claims 1 -7, wherein an SEI payloadType value of the danmaku SEI information message is included in both a list SeiProcessingOrderSeiList and a list SpoProcessSeiList.

[0094] 10. The method of any of claims 1 -9, wherein the danmaku information SEI message persists for a current picture until a next picture in output order which is associated with another danmaku information SEI message or an end of a coded layer video sequence (CLVS), whichever is earlier, and wherein the current picture is associated with the danmaku information SEI message.

[0095] 11. The method of claim 10, wherein a persistence scope of the danmaku information SEI message is specified to be a coded layer video sequence (CLVS) containing the danmaku information SEI message.

[0096] 12. The method of claim 10, wherein a persistence scope of the danmaku information SEI message is specified to be a coded video sequence (CVS) containing the danmaku information SEI message.

[0097] 13. The method of any of claims 1-12, wherein one or more syntax elements are specified to indicate one or more of a number of danmaku and a language of the danmaku in the danmaku information SEI message.

[0098] 14. The method of claim 13, wherein one syntax element is included in the bitstream to specify a number of languages or a number of languages minus 1.

[0099] 15. The method of claim 14, wherein the syntax element is coded in u(N) or is coded in ue(v) in the range of 0 to N, where N is a positive integer.

[0100] 16. The method of claim 14, wherein N is equal to 2K - 1, K is equal to 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0101] 17. The method of claim 13, wherein one syntax element is included in the bitstream to specify a number of danmakus or a number of damnakus minus 1.

[0102] 18. The method of claim 17, wherein the syntax element is coded in u(N) or is coded in ue(v) in the range of 0 to N, where N is a positive integer.

[0103] 19. The method of claim 17, wherein N is equal to 2K - 1, K is equal to 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0104] 20. The method of claim 17, wherein N is equal to 232 — 2.

[0105] 21. The method of any of claims 1-20. wherein for a danmaku, one or more syntax elements are specified to indicate content of the danmaku, and wherein the content is specified by a text string coded in st(v).

[0106] 22. The method of any of claims 1-20, wherein for a danmaku, one or more syntax elements are specified to indicate a start time of the danmaku or a time to enter a display.

[0107] 23. The method of claim 22, wherein a picture order count (POC) difference value is specified to indicate a start time of the danmaku relative to the POC value of a current picture.

[0108] 24. The method of claim 23, wherein the POC difference value is included in the bitstream using a ue(v)- coded syntax element having a value is in the range of 0 to N, inclusive, where N is a positive integer.

[0109] 25. The method of claim 24, wherein N is equal to 2K - 1, K is equal to 8, 10, 12, 14, 16, 20, or 24.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)

[0110] 26. The method of claim 25, wherein the POC difference value is signalled using a u(N)-coded syntax element, where N is 8, 10, 12, 14, 16, 20, or 24.[OHl] 27. The method of any of claims 1-26, wherein for a danmaku, one or more syntax elements are specified to indicate a duration of the danmaku or a time to exit a display.

[0112] 28. The method of claim 27, wherein a POC difference value is specified to indicate an end time for a danmaku relative to a start time.

[0113] 29. The method of claim 28, wherein the POC difference value is signalled using a ue(v)-coded syntax element having a value is in the range of 0 to N, inclusive, where N is a positive integer.

[0114] 30. The method of claim 29, wherein N is equal to 2K - 1, K is equal to 8, 10, 12, 14, 16, 20, or 24.

[0115] 31. The method of claim 30, wherein the POC difference value is signalled using a u(N)-coded syntax element, where N is 8, 10, 12, 14, 16, 20, or 24.

[0116] 32. The method of claim 31, wherein a POC difference value is specified to indicate an end time of a danmaku relative to the POC value of a current picture.

[0117] 33. The method of claim 32, wherein the POC difference value is signalled using a ue(v)-coded syntax element having a value is in the range of 0 to N, inclusive, where N is a positive integer.

[0118] 34. The method of claim 33, wherein N is equal to 2K - 1, K is equal to 8, 10, 12, 14, 16, 20, or 24.

[0119] 35. The method of claim 34, wherein the POC difference value is signalled using a u(N)-coded syntax element, where N is 8, 10, 12, 14, 16, 20, or 24.

[0120] 36. The method of claim 31, wherein a fixed duration value is included in the danmaku information SEI message.

[0121] 37. The method of claim 36, wherein whether the danmaku information SEI message is included in the bitstream depends on a value of a flag.

[0122] 38. The method of claim 36, wherein a value of the danmaku information SEI message is inferred to be equal to N when the danmaku information SEI message is not included in the bitstream.

[0123] 39. The method of claim 38, wherein N is 60.

[0124] 40. The method of claim 31, wherein, for each danmaku, a flag that indicates whether the damnaku has a fixed duration is included in the bitstream.

[0125] 41. The method of claim 40, wherein a duration of the danmaku is set equal to the fixed duration indicated in the damnaku information SEI message when the flag indicates that the danmaku has the fixed duration.

[0126] 42. The method of claim 41, wherein a syntax element that indicates an end time of the danmaku is not included in the bitstream when the flag indicates that the danmaku has the fixed duration.

[0127] 43. The method of claim 41, wherein a syntax element that indicates an end time of the danmaku is inferred to be Min(start time + a fixed duration value, maximum allowable end time) when the flag indicates that the danmaku has the fixed duration.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)

[0128] 44. The method of any of claims 1-43, wherein for a danmaku or a set of danmaku, one or more syntax elements are specified to indicate a relative position information of the danmaku or the set of danmaku in a display.

[0129] 45. The method of claim 44, wherein the relative position information includes one or more of a top, bottom, scrolling from right to left, and scrolling from left to right.

[0130] 46. The method of claim 44, wherein the relative position information indicates an exact position, wherein the exact position is relative to a video being displayed, or is an upper-left comer of the danmaku relative to the upperleft comer of the video.

[0131] 47. The method of claim 44, wherein the relative position information indicates a preferred display method of the danmaku.

[0132] 48. The method of claim 47, wherein the preferred display method is determined by a client, and wherein the client is a displayer when the danmaku is displayed.

[0133] 49. The method of claim 47, wherein the preferred display method is adjusted by a client, and wherein the client is a displayer considering the preferred display method when the danmaku is displayed.

[0134] 50. The method of claim 47, wherein a client is able to choose not to display the danmaku.

[0135] 51. The method of any of claims 1-50, wherein for a danmaku or a set of danmaku, one or more syntax elements are specified to indicate a colour of the danmaku, and wherein the color may or may not include an alpha channel.

[0136] 52. The method of claim 51, wherein a whole danmaku has a same colour.

[0137] 53. The method of claim 51, wherein each character or word of the danmaku has a different colour.

[0138] 54. The method of claim 51, wherein a syntax element is specified to indicate a colour index of the danmaku.

[0139] 55. The method of claim 54, wherein the syntax element specifies an index to a colour table.

[0140] 56. The method of claim 55, wherein the colour tabic contains one or more pre-defined colours.

[0141] 57. The method of claim 55. wherein the colour table contains one or more colours signalled in the danmaku information SEI message.

[0142] 58. The method of claim 55, wherein the colour table contains one or more colours that are updated during decoding.

[0143] 59. The method of claim 54, wherein a special index is used to indicate the colour information is directly signalled as an RGB or YUV value.

[0144] 60. The method of any of claims 1-59, wherein for a danmaku or a set of danmaku, one or more syntax elements are specified to indicate language information of the danmaku.

[0145] 61. The method of claim 60, wherein the language information is specified by a text string coded in st(v) to indicate a language tag as specified by Internet Engineering Task Force (IETF) Request for Comments (RFC) 5646.

[0146] 62. The method of claim 60, wherein a language index is specified to indicate an index to a language table.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)

[0147] 63. The method of claim 62, wherein the language table contains one or more pre-defined languages, one or more languages signalled in the danmaku information SEI message, or one or more languages updated during decoding.

[0148] 64. The method of any of claims 1-63, wherein for a danmaku or a set of danmaku, one or more syntax elements are specified to indicate a source of the danmaku.

[0149] 65. The method of claim 64, wherein one or more syntax elements are specified to indicate a user identifier (ID) from which the danmaku is generated.

[0150] 66. The method of any of claims 1-63, wherein for a danmaku, one or more syntax elements are specified to indicate an identifier (ID) of the danmaku.

[0151]

[0152] 67. The method of any of claims 1-63, wherein for a danmaku, one or more syntax elements are specified to indicate an importance of the danmaku.

[0153] 68. The method of claim 67, wherein a client is able to decide to display or not display a danmaku based on a value of the importance of the danmaku.

[0154] 69. The method of claim 67, wherein a client is able to use an importance value to determine which of two damnakus is displayed in an display area when the two damnakus would overlap would overlap in a display area.

[0155] 70. The method of any of claims 1-63, wherein for a danmaku, one or more syntax elements are specified to indicate a relationship to another danmaku.

[0156] 71. The method of claim 70, wherein one or more syntax elements are specified to indicate whether a current danmaku is a reply to another danmaku. and when yes. which danmaku.

[0157] 72. The method of claim 71, wherein one or more syntax elements are specified to indicate whether a current danmaku belongs to a certain group, and when yes, which group.

[0158] 73. The method of any of claims 1-63, wherein for a danmaku, one or more syntax elements are specified to indicate one or more of a font type of a danmaku and a font size of a danmaku.

[0159]

[0160] 74. The method of claim 73, wherein the font type of the danmaku and the font size of the danmaku are preferred parameters.

[0161] 75. The method of claim 74, wherein the preferred parameters are able to be overwritten by a client, wherein the client is a displayer when the danmaku is displayed.

[0162] 76. The method of claim 74, wherein the preferred parameters are able to be adjusted by a client, wherein the client is a displayer when the danmaku is displayed.

[0163] 77. The method of any of claims 1-63, wherein a variable is set equal to a POC value of a current picture to use a related SEI message in an interface text of an SEI message described in the Versatile Video Coding (WC) specification.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)

[0164] 78. The method of claim 77, wherein the interface text of the SEI message described in the VersatileVideo Coding (WC) specification a variable CurrPoc is set equal to PicOrderCntVal of a current picture to indicate that a picture in a same prediction unit (PU) contains the danmu information SEI message.

[0165] 79. The method of any of claims 1-78, wherein the conversion includes encoding the visual media data into the bitstream.

[0166] 80. The method of any of claims 1-78, wherein the conversion includes decoding the visual media data from the bitstream.

[0167] 81. An apparatus for processing video data comprising: a processor; and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to perform the method of any of claims 1-80.

[0168] 82. A non-transitory computer readable medium comprising a computer program product for use by a video coding device, the computer program product comprising computer executable instructions stored on the non- transitory computer readable medium such that when executed by a processor cause the video coding device to perform the method of any of claims 1-80.

[0169] 83. A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises: determining that a dedicated supplemental enhancement information (SEI) message is included in a bitstream, wherein the dedicated SEI message comprises a danmaku information SEI message carrying danmaku information; and generating a bitstream based on the determination.

[0170] 84. A method for storing bitstream of a video comprising: determining that a dedicated supplemental enhancement information (SEI) message is included in a bitstream, wherein the dedicated SEI message comprises a danmaku information SEI message carrying danmaku information; generating a bitstream based on the determination; and storing the bitstream in a non-transitory computer-readable recording medium.

[0171] 85. A method, apparatus, or system described in the present disclosure.

[0172] In the solutions described herein, an encoder may conform to the format rule by producing a coded representation according to the format rule. In the solutions described herein, a decoder may use the format rule to parse syntax elements in the coded representation with the knowledge of presence and absence of syntax elements according to the format rule to produce decoded video.

[0173] In the present disclosure, the term “video processing” may refer to video encoding, video decoding, video compression or video decompression. For example, video compression algorithms may be applied during conversion from pixel representation of a video to a corresponding bitstream representation or vice versa. The bitstream representation of a current video block may, for example, correspond to bits that are either co-located or spread in different places within the bitstream, as is defined by the syntax. For example, a macroblock may be encoded in terms of transformed and coded error residual values and also using bits in headers and other fields in the bitstream. Furthermore, during conversion, a decoder may parse a bitstream with the knowledge that some fields may be present, or absent, based on the determination, as is described in the above solutions. Similarly, an encoder may determine thatAtty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W) certain syntax fields are or are not to be included and generate the coded representation accordingly by including or excluding the syntax fields from the coded representation.

[0174] The disclosed and other solutions, examples, embodiments, modules and the functional operations described in this disclosure can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this disclosure and their structural equivalents, or in combinations of one or more of them. 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 by, or to control the operation of, 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 effecting a machine-readable propagated signal, or a combination of one or more them. The term “data processing apparatus” encompasses all apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, or multiple processors or computers. The apparatus can include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. A propagated signal is an artificially generated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal, that is generated to encode information for transmission to suitable receiver apparatus.

[0175] A computer program (also known as a program, softw are, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, and it can 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 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 coordinated files (e.g., files that store one or more modules, sub programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.

[0176] The processes and logic flows described in this disclosure can 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 can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC).

[0177] Processors suitable for the execution of a computer program include, by w ay of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read only memory or a random-access memory or both. The essential elements of a computer are a processor for performing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto optical disks, or opticalAtty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W) disks. However, a computer need not 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 by way of example semiconductor memory devices, e.g., erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto optical disks; and compact disc read-only memory (CD ROM) and Digital versatile disc-read only memory (DVD-ROM) disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

[0178] While the present disclosure contains many specifics, these should not be construed as limitations on the scope of any subject matter or of what max' be claimed, but rather as descriptions of features that max' be specific to particular embodiments of particular teclmiques. Certain features that are described in the present disclosure in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

[0179] Similarly', xvhile operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order show n or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Moreox er, the separation of various system components in the embodiments described in the present disclosure should not be understood as requiring such separation in all embodiments.

[0180] 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 the present disclosure.

[0181] A first component is directly coupled to a second component when there are no inlcrx cning components, except for a line, a trace, or another medium between the first component and the second component. The first component is indirectly coupled to the second component xvhen there are intervening components other than a line, a trace, or another medium betw een the first component and the second component. The term ‘‘coupled” and its variants include both directly coupled and indirectly coupled. The use of the term “about” means a range including ±10% of the subsequent number unless otherwise stated.

[0182] While several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods might be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated in another system or certain features may be omitted, or not implemented.

[0183] In addition, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated xvith other systems, modules, teclmiques, orAtty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W) methods without departing from the scope of the present disclosure. Other items shown or discussed as coupled may be directly connected or may be indirectly coupled or communicating through some interface, device, or intermediate component whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein.

Claims

Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)CLAIMSWhat is claimed is:

1. A method for processing media data, comprising: determining that a supplemental enhancement information (SEI) message is included in a bitstream, wherein the SEI message carries damnaku information; and performing a conversion between a visual media data and the bitstream based on the SEI message.

2. The method of claim 1, wherein the SEI message comprises a dedicated damnaku information SEI message.

3. The method of claim 1, wherein the SEI message is a text description information SEI message that is extended by adding a new purpose for damnaku information and includes one or more syntax elements to indicate related information for danmaku.

4. The method of any of claims 1 -3 , wherein the danmaku information is supported in a system level by adding a new tag for danmaku and one or more syntax elements to indicate related information for danmaku, and wherein the danmaku information is supported in the system level by timed text in International Organization for Standardization (ISO) base media format.

5. The method of any of claims 1 -4, wherein a cancellation flag syntax element is specified to cancel a previous SEI message of a same type, and wherein the SEI message of the same type comprises the danmaku information SEI message or the extended text description SEI message.

6. The method of claim 5, wherein every danmaku with a start time before an output time of a current picture is cancelled when the cancellation flag is equal to 1, and wherein the current picture is associated with a current SEI message.

7. The method of claim 5, wherein every danmaku with an end time before an output time of a current picture is cancelled when the cancellation flag is equal to 1, and wherein the current picture is associated with a current SEI message.

8. The method of any of claims 1-7, wherein the danmaku information SEI message or the extended text description SEI message is allowed to be identified in a SEI processing order (SPO) SEI message.

9. The method of any of claims 1-8, wherein an SEI payloadType value of the danmaku information SEI message or the extended text description SEI message is included in a list SeiProcessingOrderSeiList but is not included in the list SpoProcessSeiList.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)10. The method of any of claims 1-8, wherein an SEI payloadType value of the danmaku information SEI message or the extended text description SEI message is included in both a list SeiProcessingOrderSeiList and a list SpoProcessSeiList.

11. The method of any of claims 1-10, wherein the danmaku information SEI message or the extended text description SEI message persists for a current picture until a next picture in output order that is associated with another danmaku information SEI message or another extended text description SEI message or an end of a coded layer video sequence (CLVS), whichever is earlier, and wherein the current picture is associated with the danmaku information SEI message or the extended text description SEI message.

12. The method of claim 11, wherein a persistence scope of the danmaku information SEI message or the extended text description SEI message is specified to be a coded layer video sequence (CLVS) containing the danmaku information SEI message or the extended text description SEI message, respectively.

13. The method of claim 11, wherein a persistence scope of the danmaku information SEI message or the extended text description SEI message is specified to be a coded video sequence (CVS) containing the danmaku information SEI message or the extended text description SEI message, respectively.

14. The method of any' of claims 1-13, wherein one or more syntax elements are specified to indicate one or more of a number of danmaku and a language of the danmaku in the danmaku information SEI message or the extended text description SEI message.

15. The method of claim 14, wherein one syntax element is included in the bitstream to specify a number of languages or a number of languages minus 1.

16. The method of claim 1 , wherein the syntax element is coded in u(N) or is coded in ue(v) in the range of 0 to N, where N is a positive integer.

17. The method of claim 15, wherein N is equal to 2K- 1, K is equal to 2. 3, 4, 5, 6, 7, 8. 9, or 10.

18. The method of claim 14, wherein one syntax element is included in the bitstream to specify a number of danmakus or a number of danmakus minus 1.

19. The method of claim 18, wherein the syntax element is coded in u(N) or is coded in ue(v) in the range of 0 to N, where N is a positive integer.

20. The method of claim 19, wherein N is equal to 2K- 1, K is equal to 2, 3, 4, 5, 6, 7, 8, 9 or 10.Atty. Dkt. No.: 4824-71704 (P24102494999WO1; G25N22734W)21. The method of claim 19, wherein N is equal to 232- 2.

22. The method of any of claims 1-21, wherein a variable is set equal to a picture order count (POC) value of a current picture in an interface text of an SEI message described in the Versatile Video Coding (VVC) specification to use an SEI message that includes danmaku information.

23. The method of claim 22, wherein in the interface text of the SEI message described in the VVC specification, a variable CurrPoc is set equal to PicOrderCntVal of a current picture to indicate that a picture in a same prediction unit (PU) contains the danmaku information SEI message or the extended text description SEI message.

24. The method of any of claims 1-23, wherein the conversion includes encoding the visual media data into the bitstream.

25. The method of any of claims 1-23, wherein the conversion includes decoding the visual media data from the bitstream.

26. An apparatus for processing video data comprising: a processor; and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to perform the method of any of claims 1-25.

27. A non-transitory computer readable medium comprising a computer program product for use by a video coding device, the computer program product comprising computer executable instructions stored on the non- transitory’ computer readable medium such that when executed by’ a processor cause the video coding device to perform the method of any of claims 1-25.

28. A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises: determining that a supplemental enhancement information (SEI) message is included in a bitstream, wherein the SEI message carries danmaku information; and generating a bitstream based on the determination.

29. A method for storing bitstream of a video comprising: determining that a supplemental enhancement information (SEI) message is included in a bitstream, wherein the SEI message carries danmaku information; generating a bitstream based on the determination; and storing the bitstream in a non-transitory computer-readable recording medium.

Images