Presence and content of the digitally signed content SEI messages

Abstract

A mechanism for processing video data is disclosed The mechanism includes determining that, within a verification period for a particular digitally signed content initialization (DSCI) identifier (dsci_id) value (dscIdVal), a digitally signed content verification (DSCV) supplemental enhancement information (SEI) message for each of a plurality of verification substreams for the particular dsci_id value (dscIdVal) to which at least one network abstraction layer (NAL) unit is assigned shall be present. A conversion is performed between a visual media data and a bitstream based on the DSCV SEI message.

Description

PRESENCE AND CONTENT OF THE DIGITALLY SIGNED CONTENT SEI MESSAGESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims the benefit of U. S. Pat. Application No. 63 / 774,021 filed on March 18, 2025, which is hereby incorporated by reference.TECHNICAL FIELD

[0002] The present disclosure relates to generation, storage, and consumption of digital audio video media information in a file fonnat.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 media data, comprising: determining that, within a verification period for a particular digitally signed content initialization (DSCI) identifier (dsci_id) value (dsddVal), a digitally signed content verification (DSC V l supplemental enhancement information (SEI) message for each of a plurality of verification substreams for the particular dsci_id value (dscIdVal) to which at least one network abstraction layer (NAL) unit is assigned shall be present; and performing a conversion between a visual media data and a bitstream based on the DSCV SEI message.

[0005] Optionally, in any of the preceding aspects, another implementation of the aspect provides that there is one and only one DSCV SEI message for each of the plurality of verification substreams for the particular dsci_id value (dsddVal) to which the at least one network abstraction layer (NAL) unit is assigned.

[0006] Optionally, in any of the preceding aspects, another implementation of the aspect provides that, within the current verification period, there shall be no verification substream member NAL unit of a verification substream with a verification substream identifier (ID) equal to a DSCV SEI verification substream identifier (ID) succeeding a current prediction unit (PU) in decoding order.

[0007] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the current PU comprises a PU containing a current DSCV SEI message.

[0008] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the DSCV SEI message provides a mechanism for verifying a digital signature of a verification substream indicated in the DSCI SEI message identified by the DSCI identifier (dsci_id) equal to a DSCV identifier (dscv_id).

[0009] Optionally, in any of the preceding aspects, another implementation of the aspect provides that, when a coded video sequence (CVS) does not contain a DSCI SEI message, the CVS shall not contain a DSCV SEI message.

[0010] Optionally, in any of the preceding aspects, another implementation of the aspect provides that, when the CVS does not contain a DSCI SEI message with the particular DSCI identifier (dsci_id) value (dscIdVal), the CVS shall not contain a DSCV SEI message with the DSCI identifier (dsci_id) equal to the particular DSCI identifier (dsci_id) value (dscIdVal).

[0011] Optionally, in any of the preceding aspects, another implementation of the aspect provides that, when an access unit (AU) contains both a DSCI SEI message and a DSCV SEI message, the DSCI SEI message shall precede the DSCV SEI message.

[0012] Optionally, in any of the preceding aspects, another implementation of the aspect provides that, when the AU contains both a DSCI SEI message the particular DSCI identifier (dsci id) value (dscldVal) and a DSCV SEI message with a DSCV identifier (dscv_id) equal to the particular DSCI identifier (dsci_id) value (dscIdVal), the DSCI SEI message shall precede the DSCV SEI message.

[0013] Optionally, in any of the preceding aspects, another implementation of the aspect provides that, when a prediction unit (PU) contains both a digitally signed content selection (DSCS) SEI message and a DSCV SEI message, the DSCS SEI message shall precede the DSCV SEI message.

[0014] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the DSCV identifier (dscv_id) contains an identifying number of a verification system that may be applied for verifying that coded video has been produced by a content provider indicated by an associated DSCV SEI message.

[0015] Optionally, in any of the preceding aspects, another implementation of the aspect provides that a DSCV verification substream identifier (dscv_verification_substream_id) specifies a verification substream ID of a verification substream to which the DSCV SEI message applies.

[0016] Optionally, in any of the preceding aspects, another implementation of the aspect provides that a DSCV signature (dscv_signature) contains a digital signature for a verification substream indicated by the DSCV verification substream identifier (dscv_verification_substream_id).

[0017] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the DSCV identifier (dscv_id) is coded as an 8-bit unsigned integer (u(8)).

[0018] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the DSCV identifier (dscv_id) is a first syntax element coded in the DSCV SEI message.

[0019] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the conversion includes encoding the visual media data into the bitstream.

[0020] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the conversion includes decoding the visual media data from the bitstream.

[0021] 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 the method of any of the disclosed aspects.

[0022] A third aspect relates to 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 the disclosed aspects.

[0023] 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: determining that, within a verification period for a particular digitally signed content initialization (DSCI) identifier (dsci_id) value (dscIdVal), a digitally signed content verification (DSCV) supplemental enhancement information (SEI) message for each of a plurality of verification substreams for the particular dsci_id value (dscIdVal) to which at least one network abstraction layer (NAL) unit is assigned shall be present; and generating a bitstream based on the determination.

[0024] A fifth aspect relates to a method for storing bitstream of a video, comprising: determining that, within a verification period for a particular digitally signed content initialization (DSCI) identifier (dsci_id) value (dscIdVal), a digitally signed content verification (DSCV) supplemental enhancement information (SEI) message for each of a plurality of verification substreams for the particular dsci_id value (dscIdVal) to which at least one network abstraction layer (NAL) unit is assigned shall be present; generating the bitstream based on the determination; and storing the bitstream in a non-transitory computer-readable recording medium.

[0025] A sixth aspect relates to a method, apparatus, or system described in the present disclosure.

[0026] 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.

[0027] 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

[0028] For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.

[0029] FIG. 1 is a block diagram showing an example video processing system.

[0030] FIG. 2 is a block diagram of an example video processing apparatus.

[0031] FIG. 3 is a flowchart for an example method of video processing.

[0032] FIG. 4 is a block diagram that illustrates an example video coding system.

[0033] FIG. 5 is a block diagram that illustrates an example encoder.

[0034] FIG. 6 is a block diagram that illustrates an example decoder.

[0035] FIG. 7 is a schematic diagram of an example encoder.DETAILED DESCRIPTION

[0036] It should be understood at the outset that although an illustrative implementation of one or more embodiments are provided below, 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.

[0037] Section headings are used in the present disclosure for ease of understanding and do not limit the applicability of techniques and embodiments disclosed in each section only to that section. Furthermore, H.266 terminology is used in some description only for ease of understanding and not for limiting scope of the disclosed techniques. As such, the techniques described herein are applicable to other video codec protocols and designs also. In the present disclosure, editing changes are shown with respect to the Versatile Video Coding (WC) specification.1. Initial discussion

[0038] This disclosure is related to image / video coding technologies. Specifically, this disclosure is related to constraints on presence and content for the digitally signed content (DSC) initialization (DSCI) SEI message and the digitally’ signed content verification (DSCV) SEI message. 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 supplemental enhancement information (VSEI) messages for coded video bitstreams standard.2. Abbreviations

[0039] Adaptation parameter set (APS), access unit (AU), coded layer video sequence (CLVS), coded layer video sequence start (CLVSS), cyclic redundancy check (CRC), coded video sequence (CVS), finite impulse response (FIR), intra random access point (TRAP), network abstraction layer (NAL), neural -network postprocessing filter (NNPF), neural-network post-filter activation (NNPFA), neural-network post-filter characteristics (NNPFC), picture parameter set (PPS), picture unit (PU), random access skipped leading (RASL) picture, supplemental enhancement information (SET), step-wise temporal sublayer access (STSA), uniform resource identifier (URI), video coding lay’er (VCL), versatile supplemental enhancement information as described in Rec. ITU-T H.274 | ISO / IEC 23002-7 (VSEI), video usability’ information (VUI), versatile video coding as described in Rec. ITU-T H.266 | ISO / IEC 23090-3 (WC)3. Further discussion3.1 Video coding standards

[0040] Video coding standards have evolved primarily through the development of International Telecommunication Union (ITU) telecommunication standardization sector (ITU-T) and International Organization for Standardization (ISO) / International Electrotechnical Commission (IEC) standards. The ITU-T produced H.261 and H.263, ISO / IEC produced motion picture experts group (MPEG)-l 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 / high efficiency video coding (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 video coding technologies beyond high efficiency video coding (HEVC), the Joint Video Exploration Team (JVET) was founded by video coding experts group (VCEG) and motion picture experts group (MPEG). Further, 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 (VVC) project officially started. VVC 131 is a coding standard targeting at 50% bitrate reduction as compared to HEVC.

[0041] The Versatile Video Coding (VVC) 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 / IEC 23002-7) |4] arc designed for use in a maximally broad range of applications, including both the simple uses such as television broadcast, video conferencing, or playback from storage media, and also more advanced use cases such as adaptive bit rate streaming, video region extraction, composition and merging of content from multiple coded video bitstreams, multi-view video, scalable layered coding, and viewport-adaptive 360° immersive media.

[0042] The Essential Video Coding (EVC) standard (ISO / IEC 23094-1) is another video coding standard under development by MPEG.3.2 SEI messages in general and in WC and VSEI|0043| 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.

[0044] 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 which the sy ntax and semantics are specified in ITU-T H.274 | ISO / IEC 23002-7.3.3. Digitally Signed Content (DSC) SEI messages

[0045] In an example, a digitally signed content initialization (DSCI) SEI message, a digitally signed content selection (DSCS) SEI message, and a digitally signed content verification (DSCV) SEI message are specified. These three SEI messages are collectively referred to as the DSC SEI messages.

[0046] An example implementation of the DSC SEI messages is as follows.8.38 Digitally signed content initialization SEI message8.38.1 Digitally signed content initialization SEI message syntaxdigitally_signed_content_initialization( payloadSize ) { Descriptordsci id u(8) dsci hash method type u(8) dsci key source uri st(v) dsci num verification substreams minusl ue(v) for( i = 1; i <= dsci_num_verification_substreams_minusl; i++ )for( j = 0; j < i; j++ )dsci_ref_substream_flag[ i ][ j ] u(l) dsci key retrieval mode idc ue(v) if( dsci_key_retrieval_mode_idc = = 1){dsci_use_key_register_idx_flag u(l) if( dsci_use_key_register_idx_flag )dsci key register idx ue(v) }dsci content uuid present flag u(l) if( dsci_content_uuid_present_flag)dsci content uuid u(128) }8.38.2 Digitally signed content initialization SEI message semantics

[0047] Use of this SEI message requires the definition of the following:– A lists of non-VCL NAL unit type identifiers nonVclDigitallySignedNalUnitsList.

[0048] The digitally signed content initialization SEI message, digitally signed content selection SEI message, and digitally signed content verification SEI message provide a mechanism for verifying that the coded video has been produced by a content provider that identifies itself via the digital certificate that is referenced in the digitally signed content initialization SEI message. This SEI message also provides information about the secure hash algorithm used for calculating message digests, which are used together with the digital signature present in digitally signed content verification SEI messages to verify the trustworthiness of non-VCL NAL units with a NAL unit type identifier among the values in nonVclDigitallySignedNalUnitsList and VCL NAL units present in the coded video sequence. It further provides information about the digital signature algorithm used and the public key of the content provider. The digitally signed content initialization SEI message may provide the public key of the content provider either by providing an URI that identifies a trust record that contains the certificate of the content provider or by providing an URI that directly identifies the certificate.

[0049] When a digitally signed content initialization SEI message is present in any AU of a CVS, all of the following shall be true:- A digitally signed content initialization SEI message shall be present in the first IDR, CRA and GDR PU present in any AU in the CVS.- The digitally signed content initialization SEI message shall precede all non-VCL NAL units with a NAL unit ty pe identifier among the values in nonVclDigitallySignedNalUnitsList and VCL NAL units of the AU. - There shall be present at most one digitally signed content initialization SEI message having a particular value of dsci id in an AU.

[0050] The digitally signed content initialization SEI message applies to the current coded picture and all following coded pictures until one or more of the following conditions are true:The bitstream ends.A new CVS begins.- A new digitally signed content initialization SEI message is received.

[0051] When a digitally signed content initialization SEI message is present in an AU of a CVS, a digitally signed content verification SEI message shall be present for each of the substreams that a NAL unit is assigned to. The signed content verification SEI message shall be present in the bitstream before one or more of the following conditions are true:The bitstream ends.- A new CVS begins.- A new digitally signed content initialization SEI message is received.

[0052] dsci id contains an identifying number that may be used to identify a mechanism for verifying that the coded video has been produced by a content provider.

[0053] All digitally signed content verification SEI message having a particular value of dsci id that apply to the same CLVS shall have the same content. dsci_hash_method_type indicates the secure hash algorithm that is used to calculate message digests for subsets of non-VCL NAL units with a NAL unit type identifier among the values in nonVclDigitallySignedNalUnitsList and VCL NAL units of the coded video sequence. Based on these message digests and the digital signatures present in digitally signed content verification SEI messages, a decoder can verify that the coded video was produced by the content originator indicated by the syntax elements dsci_key_source_uri, dsci_use_key_register_idx_flag and, if dsci_use_key_register_idx_flag flag is equal to 1, dsci key register idx. The supported values for the syntax element dsci hash method type, the block size used for calculating the message digest, and the size of the calculated message digests arc specified. Values of dsci hash method type that are not listed in the Table XXX are reserved for future use by ITU-T | ISO / IEC andshall not be present in payload data conforming to this version of this Specification. Decoders shall ignore trustworthy initialization SEI messages that contain reserved values for dsci hash method type. The secure hash algorithms listed in Table XXX are specified in the “Secure Hash Standard” NIST FIPS PUB 180-4.Table XXX – Supported values of dsci_hash_method_typedsci_hash_method_type Hash method Block size (bits) Message digest size (bits)0 SHA-1 512 160 1 SHA-224 512 224 2 SHA-256 512 256 3 SHA-384 1024 384 4 SHA-512 1024 512 5 SHA-512 / 224 1024 224 6 SHA-512 / 256 1024 256

[0054] dsci key source uri contains a URI with syntax and semantics. If dsci key retrieval mode idc is equal to 0, dsci_key_source_uri specifies a trust record. If dsci_key_retrieval_mode_idc is equal to 1, the following applies:- If dsci use key register idx flag is equal to 0, the URI identifies the certificate of the content provider that can be used for verifying the signatures present in following digitally signed content verification SEI messages;- Otherwise (if dsci_use_key_register_idx_flag is equal to 1), the URI identifies a register of certificates and the certificate of the content provider that can be used for verifying the signatures present in following digitally signed content verification SEI messages as indicated by dsci_key_register_idx.

[0055] dsci num verification substreams minus 1 plus 1 indicates the number of substreams for which message digests are calculated and signatures may be present in following digitally signed content verification SEI messages. The value of dsci num verification substreams minusl shall be in the range of 0 to 255, inclusive.The variable NumVerificationSubstream is derived as:NumVerificationSubstream = dsci num verification substreams minusl + 1.

[0056] dsci_ref_substream_flag[ i ][j ] equal to 1 specifies that the i-th substreani depends on the j -th substrcani. dsci_rcf_substrcam_flag[ i || j J equal to 0 specifics that the i-th substreani docs not depend on the j-th substream.

[0057] When not present, the value of dsci_ref_substream_flag[ i ][ j ] is inferred to be equal to 0.

[0058] DscRefSubstreamId[ i ][refIdx], DscNumRefSubstreamf i ] and IndependentNonBaseSubstreams are derived as follows:IndependentNonBaseSubstreams = 0for( i = 0; i <= dsci num verification substreams minusl; i++ ) {DscNumRefSubstream[ i ] = 0for(j = 0, refIdx = 0, j < i; j++ )if( dsci ref substream flag[ i ][j ] ) {DscRefSubstreamId[ i ][ refIdx++ ] = jDscNumRefSubstreams[ i ]++}if (i > 0 && DscNumRefSubstreams[ i ] = = 0)IndependentNonBaseSubstreams = 1}

[0059] When dsci_ref_substream_flag[ i ][ j ] is equal to 1 and dsci_ref_substream[ j ][ k ] is equal to 1 for any values of j less than i and k less than j, dsci ref substream [ i ][ k ] shall be equal to 1.

[0060] dsci_key_retrieval_mode_idc equal to 0 indicates that the URI contained in dsci_key_source_uri specifies a trust record, dsci_key_retrieval_mode_idc equal to 1 indicates that the URI contained in dsci_key_source_uri and, when present, dsci_key_register_idx specify a certificate. In this version of this Specification dsci_key_retrieval_mode_idc shall be in the range of 0 to 1. Decoders shall also allow other values of dsci_key_retrieval_mode_idc, but shall ignore the content of the digitally signed content initialization SEI message, associated digitally signed content selection SEI messages and associated digitally signed content verification SEI messages.

[0061] dsci_use_key_register_idx_flag equal to 1 indicates that the URI contained in dsci_key_source_uri specifies a register of certificates and the syntax element dsci_key_register_idx is present in the SEI message. dsci_use_key_register_idx_flag equal to 0 indicates that the URI contained in dsci_key_source_uri specifies a certificate and the syntax element dsci_key_register_idx is not present in the SEI message.

[0062] When dsci key retrieval mode ide is equal to 0, the media asset for which the last trust manifest within the trust record provides content binding is the digitally signed content initialization SEI message. The following constraints apply to the trust record identified by the dsci_key_source_uri:- The last trust manifest within the trust record shall contain exactly one hard binding data hash assertion with a label equal to c2pa.hash.data.- The schema for data hash assertion is defined by the data-hash-map rule in the following CDDL Definition:; The data structure used to store the cryptographic hash of some or all of the asset's data; and additional information required to compute the hash.data-hash-map = {? "exclusions": [1* EXCLUSION RANGE-map],; Ranges have monotonically increasing start' values, and no two ranges may overlap.? "alg":tstr .size (1..max-tstr-length),; A string identifying the cryptographic hash algorithm used to compute the hash in this assertion."hash": bstr,; byte string of the hash value"pad": bstr,; zero-filled byte string used for filling up space? "pad2": bstr,; optional zero-filled byte string used for filling up space? "name": tstr .size (1..max-tstr-length),; (optional) a human-readable description of what this hash cover? "url": uri,; Unused and deprecated.}EXCLUSION_RANGE-map = {"start": int,; Starting byte of the range"length": int,; Number of by tes of data to exclude}- The exclusion range specifying the data in the digitally signed content initialization SEI message that is excluded when computing the hash value and indicated in the data hash assertion shall match the dsci key source uri bytes in the digitally signed content initialization SEI message.

[0063] dsci_key_register_idx, when present, contains an index that specifies the certificate of the content provider, in the certificate register indicated by dsci key source uri, which can be used for verifying the signatures present in following digitally signed content verification SET messages. The value of dsci_key_register_idx shall be in the range of 0 to 1023, inclusive.

[0064] The certificate indicated by the syntax elements dsci_key_retrieval_mode_idc, dsci_use_key_register_idx_flag, dsci_key_source_uri, and, if dsci_use_key_register_idx_flag is equal to 1, dsci_key_register_idx shall specify a digital signature method, with associated parameters (if applicable), and thepublic key of the content provider. When dsci_key_retrieval_mode_idc is equal to 1, the format in which this information is provided is outside the scope of this specification. It is suggested that a digital signature algorithm conforming to the “Digital Signature Standard” NIST FIPS 186-5 is used.

[0065] dsci_content_uuid_present_flag equal to 1 specifies that the syntax element dsci_content_uuid is present. dsci_content_uuid_present_flag equal to 0 specifies that the syntax element dsci_content_uuid is not present. When dsci_key_retrieval_mode_idc is equal to 0 or IndependentNonBaseSubstreams is equal to 1, dsci content uuid present flag shall be equal to 1.

[0066] dsci_content_uuid, when present, indicates an identifier for the video content and shall have a value specified as a Universally Unique Identifier (UUID).

[0067] When a digitally signed content initialization SEI message is present in an AU, the calculation of Num Verification Substream message digests is initialized for the specified dsci hash method type. Each non-VCL NAL unit with a NAL unit type identifier among the values in nonVclDigitallySignedNalUnitsList and VCL NAL unit following the digitally signed content initialization SEI message is associated to one of the Num Verification Substream message digests; the verification substream id is either indicated by the digitally signed content selection SEI message or, if no digitally signed content selection SEI message is present for a PU, inferred to be equal to 0. The message used for calculating the k-th message digest, with k being in the range from 0 to dsci num verification substreams minus 1, inclusive, is obtained by concatenating all non-VCL NAL units with a NAL unit type identifier among the values in nonVclDigitallySignedNalUnitsList and VCL NAL units associated with the k-th verification substream. The calculation of the message digests is conducted based on blocks, where the block size is specified in Table XXX depending on the value of dsci_hash_method_type. For each non-VCL NAL unit with a NAL unit type identifier among the values in nonVclDigitallySignedNalUnitsList and VCL NAL unit, the associated message digest is updated for the specified dsci hash method type. Note that, since the message digests are calculated for the concatenation of all non-VCL NAL units with a NAL unit type identifier among the values in nonVclDigitallySignedNalUnitsList and VCL NAL units for a verification substream, some of the processing blocks typically span over two or more successive NAL units.8.39 Digitally signed content selection SEI message8.39.1 Digitally signed content selection SEI message syntaxdigitally_signed_content_selection( payloadSize ) { Descriptor dscs_id u(8) dscs_verification_substream_id u(8)}8.39.2 Digitally signed content selection SEI message semantics

[0068] Use of this SEI message requires the definition of the following:– A lists of non-VCL NAL unit type identifiers nonVclDigitallySignedNalUnitsList.

[0069] The digitally signed content selection SEI message provides a mechanism for associating coded pictures with one of the verification substreams indicated in a digitally signed content initialization SEI message identified by dsci_id equal to dscs_id.

[0070] When an AU contains both a digitally signed content initialization SEI message identified by dsci id equal to dscs_id and a digitally signed content selection SEI message identified by dsci_id equal to dscs_id, the digitally signed content initialization SEI message identified by dsci_id equal to dscs_id shall precede the digitally signed content selection SEI message identified by dsci id equal to dscs_id in decoding order.

[0071] When a CVS does not contain a digitally signed content initialization SEI message, CLVSs of the CVS shall not contain a digitally signed content selection SEI message.

[0072] When a digitally signed content selection SEI message is present in any PU of a CL VS, it shall precede all non-VCL NAL units with a NAL unit type identifier among the values in nonVclDigitallySignedNalUnitsList and VCL NAL units of the PU.

[0073] dscs id contains an identifying number that may be used to identify a mechanism for verifying that the coded video has been produced by a content provider.

[0074] dscs verification substream id mdicates the verification substream to which the non-VCL N / L units with a NAL unit type identifier among the values in nonVclDigitallySignedNalUnitsList and VCL NAL units of the current coded picture are assigned to. When a digitally signed content initialization SEI message was present in the current coded video sequence, but no corresponding digitally signed content selection SEI message identified by dsci_id equal to dscs_id is present for a coded picture, the value of dscs_verification_substream_id and the value of dscs id are inferred to be equal to 0. The value of dscs verification substream id shall be in the range from 0 to dsci_num_verification_substreams_minusl, inclusive.

[0075] The message digest for the verification substream with id equal to dscs_verification_substream_id is updated with the non-VCL NAL units with a NAL unit type identifier among the values in nonVclDigitallySignedNalUnitsList and VCL NAL units of the current coded picture according to the dsci_hash_method_type specified in the corresponding digitally signed content initialization SEI message identified by dsci id equal to dscs id.8.40 Digitally signed content verification SEI message8.40.1 Digitally signed content verification SEI message syntaxdigitally _signed_content_verification( payloadSize ) { Descriptor dscv_id u(8) dscv_verification_substream_id u(8) dscv_signature_length_in_octets_minus1 u(16) dscv_signature u(v)8.40.2 Digitally signed content verification SEI message semantics

[0076] Use of this SEI message requires the definition of the following:– A lists of non-VCL NAL unit type identifiers nonVclDigitallySignedNalUnitsList.

[0077] The digitally signed content verification SEI message provides a mechanism for verifying the digital signature of a substream indicated in a digitally signed content initialization SEI message indicated by dsci_id equal to dscv_id.

[0078] When a CVS does not contain a digitally signed content initialization SEI message identified by dsci_id equal to dscv_id, CLVSs of the CVS shall not contain digitally signed content verification SEI message identified by dsci id equal to dscv id.

[0079] When an AU contains both a digitally signed content initialization SEI message identified by dsci_id equal to dscv_id and a digitally signed content verification SEI message identified by dsci_id equal to dscv_id, the digitally signed content initialization SEI message shall precede the digitally signed content verification SEI message. When a PU contains both a digitally signed content selection SEI message identified by dsci_id equal to dscv id and a digitally signed content verification SEI message identified by dsci id equal to dscv id, the digitally signed content selection SEI message shall precede the digitally signed content verification SEI message.

[0080] When a digitally signed content verification SEI message identified by dsci id equal to dscv id is present in a PU of a CVS, no non-VCL NAL units with a NAL unit type identifier among the values in nonVclDigitallySignedNalUnitsList or VCL NAL unit shall be assigned to the substream that is indicated by dscv verification substream id, unless one or more of the following conditions are true:- The bitstream ends.- A new CVS begins.- A new digitally signed content initialization SEI message is received.

[0081] dscv id contains an identifying number that may be used to identify a mechanism for verify ing that the coded video has been produced by a content provider.

[0082] dscv_verification_substream_id indicates the verification substream to which the SEI message applies.

[0083] It is constrained that the value of dscv_verification_substream_id of the first digitally signed content verification SEI message having a particular dscv_id value currDscvId that follows the last digitally signed content initialization SEI message having the dsci_id value equal to currDscvId, in decoding order, shall be equal to 0.

[0084] Note 1 - When a new digitally signed content initialization SEI message with a particular identifier is present, new value space for substream identifiers in digitally signed content selection SEI messages (i.e.,dscs verification substream id) and digitally signed content verification SEI (i.e., dscv verification substream id ) with the same identifier is used.

[0085] dscv_signature_length_in_octets_minus1 plus 1 specifies the length of the syntax element dscv_signature in octets (one octet consists of 8 bits).

[0086] dscv signature contains the digital signature for the verification substream indicated by dscv verification substream id.

[0087] The variable sld is set equal to dscv verification substream id.

[0088] The variable numRefs is set equal to DscNumRefSubstreams[ sld ].

[0089] The verification of the bitstream signature consists of the following ordered steps:1. The calculation of the message digest referred to as CurrDigest is finalized as follows:- The concatenation of the non-VCL NAL units with a NAL unit type identifier among the values in nonVclDigitallySignedNalUnitsList and VCL NAL units for the verification substream with id equal to dscv_verification_substream_id is padded. Note that it is sufficient to pad the last NAL unit of the verification substream.- The calculation of the message digest CurrDigest is finalized. The length (in bits) of the message digest is given in Table XXX.2. The reference message digest RefDigest[ refIdx ] for refIdx in the range of 0 .. numRefs, inclusive, is determined as follows:- If numRefs is greater than 0, the following applies:i. The reference message digest RefDigest[ refldx ] for each value of refldx in the range of 1.. numRefs, inclusive, is set to the value of CurrDigest in the previous digitally signed content verification SEI message in decoding order with dscv verification substream id equal to DscRefSubstreamId[ sld ] [ refldx - 1 ]. It is a requirement of bitstream conformance that the digitally signed content verification SEI message associated with verification substrcam id equal to DscRefSubstreamId[ sld ][ refldx- 1 ] shall be present before the digitally signed content verification SEI message with verification substream id equal to sld. ii. If the current digitally signed content verification SEI message with dscv_verification_substream_id equal to DscRefSubstreamId[ sId ]

[0000] is the first digitally signed content verification SEI in the coded video sequence and the preceding coded video sequence did not contain any digitally signed content initialization SEI message with dscv_verification_substream_id equal to DscRefSubstreamId[ sId ]

[0000] (this includes the case that the current coded video sequence is the first coded video sequence in the bitstream),RefDigest

[0000] is set equal to a bitstring that consists of DigestSize bits equal to 1, where DigestSize is the size of the message digest as specified in Table XXX.Otherwise, the reference message digest RefDigest

[0000] is the last calculated message digest for the verification substream with id equal to DscRefSubstreamId[ sId ]

[0000] .- Otherwise, if the current digitally signed content verification SEI message is the first digitally signed content verification SEI with verification id equal to sld in the coded video sequence and the preceding coded video sequence did not contain any digitally signed content initialization SEI message (this includes the case that the current coded video sequence is the first coded video sequence in the bitstream), the RefDigest is set equal to a bitstring that consists of DigestSize bits equal to 1, where DigestSize is the size of the message digest as specified in Table XXX.- Otherwise, the reference message digest RefDigest is the last calculated message digest for the verification substream with id equal to sld.3. The identification string IdString is constructed by concatenating the binary representations of the reference message digest RefDigest[ refldx ], for refldx in 0.. numRefs, inclusive, the current message digest, and the dsci_hash_method_type and, when present, the dsci_content_uuid, as illustrated in Figure XXX.RefDigest[ refldx ] for CurrDigest dsci_hash_method_type dsci content uuid refldx in 0. numRefs (when present)Figure XXX - Construction of identification string IdStringThe number of bits for RefDigest[ refldx ] is determined by the value of dsci hash method type which was valid when calculating the value of RefDigest) refldx ], the number of bits for CurrDigest is determined by the current value of dsci_hash_method_type, and the value of dsci_hash_method_type is represented with 8 bits and, when present, the value of dsci_content_uuid is represented with 128 bits.4. The identification string IdString represents the message used for verifying the signature. The signature verification algorithm and the public key used for verifying the signature are indicated by the syntax elements dsci_use_key_register_idx_flag, dsci_key_source_uri, and, if dsci_use_key_register_idx_flag is equal to 1, dsci_key_register_idx.

[0090] NOTE 1 – Since the bitstring used for signature verification includes the RefDigest, it cannot only be verified that the non-VCL NAL units with a NAL unit type identifier among the values in nonVclDigitallySignedNalUnitsList and VCL NAL units used for calculating the current message digest are correct, but it can additionally be verified that neither additional non-VCL NAL units with a NAL unit type identifier among the values in nonVclDigitallySignedNalUnitsList and VCL NAL units were added to thebitstream nor non-VCL NAL units with a NAL unit type identifier among the values in nonVclDigitallySignedNalUnitsList and VCL NAL units were removed from the bitstream.

[0091] NOTE 2 – When a decoder tunes into a bitstream, the IdString constructed for the first digitally signed content verification SEI message cannot be verified, because the value of RefDigest cannot be calculated correctly. But starting from the second digitally signed content verification SEI message, the signatures can be verified.- It is a requirement of bitstream conformance that when verification of a verification substream substream A with dscv_verification_substream_id value greater than 0 uses reference message digest from a verification substream substreamB, both of the following shall be true:- NAL units of PUs that are associated with substreamB shall not belong to a layer that is higher than the highest layer of the NAL units of PUs that arc associated with substrcamA.- When the highest layer of NAL units in substreamA and substreamB is equal, NAL units PUs that are associated with substreamB shall not belong to temporal sub layer that is higher than the highest temporal sub layer of the NAL units of PUs that are associated with substreamA.

[0092] After verification, the message digest for the verification substream with id equal to dscv verification substream id is reinitialized for the specified dsci hash method type.4. Technical problems solved by disclosed technical solutions

[0093] An example design of the DSC SEI messages has the following problems:

[0094] First, when a DSCI SEI message is present in any AU of a CVS, a DSCI SEI message shall be present in the first instantaneous decoder refresh (IDR), clean random access (CRA), and gradual decoding refresh (GDR) prediction unit (PU) present in any AU in the CVS. There are three issues herein. First, the DSCI SET message applies across layers thus is an AU-level SEI message. Second, the constraint should be on DSCI SEI messages with the same dsci_id value. Third, the terms GDR picture / PU / AU are not defined.

[0095] Second, requiring all DSCI SEI messages having a particular value of dsci id within a CVS to have the same content can make the design simpler.

[0096] Third, it is allowed to have more than one DSCV SEI message present in a verification period for one particular verification substream. However, requiring the number be one and only one can make the design simpler.

[0097] Fourth, it is allowed for a DSCV SEI message with dscv_id equal to a particular value dscIdVal to be present in an AU that is not the last AU in decoding order in the verification period for dsci_id equal to dscIdVal. However, requiring the presence m the last AU can make the design simpler.

[0098] Fifth, it is specified that, when a PU contains both a DSCS SEI message identified by dscs id equal to a particular value and a DSCV SEI message identified by dsev id equal to the same particular value, the DSCS SEI message shall precede the DSCV SEI message in decoding order. However, it is possible, and sometimesbeneficial to have all DSCV SEI messages in the end of an AU hence in the very last PU of the AU while some of the corresponding DSCS SEI messages are in other PUs of the AU for assigning those PUs to various verification substreams. Therefore, to cover such cases, the constraint should be rephrased in AU level.

[0099] Sixth, it is specified that, within the current verification period, there shall be no verification NAL unit of the verification substrcam with verification substrcam ID equal to dscv_vss_id succeeding the current DSCV SEI message in decoding order. However, some VCL NAL units within the current PU and succeeding the current DSCV SEI message in decoding order should be allowed, which enables repetition of a particular DSCV SEI message within a PU.

[0100] Seventh, when repetition of a particular DSCV SEI message within a PU is allowed, a constraint is needed to make sure that the repetitions are actually repetitions.5. A listing of solutions and embodiments

[0101] To solve the above-described problems, methods as summarized below are disclosed. The aspects should be considered as examples to explain the general concepts and should not be interpreted in a narrow way. Furthermore, these examples can be applied individually or combined in any manner.1) In one example, it is specified that, when a DSCI SEI message with a particular dsci_id value dscIdVal is present in any AU of a CVS, a DSCI SEI message with dsci id equal to dscIdVal shall be present in each TRAP or GDRAU in the CVS.a. In one example, a gradual decoding refresh (GDR) picture is defined as a coded picture starting from which all pictures in the same layer in both decoding order and output order can be decoded without first decoding any picture in die same layer earlier in decoding order in the coded video bitstream, and starting from a subsequent picture in decoding order for all pictures in the same layer in both decoding order and output order the cropped decoded pictures are fully correct. b In one example, a GDR AU is defined as an AU in which each coded picture is a GDR picture 2) In one example, it is specified that all DSCI SEI messages with a particular value of dsci_id within a CVS shall have the same content.3) In one example, it is specified that, within a verification period for a particular dsci_id value, one and only one DSCV SEI message for each of the verification substreams for the particular dsci id value to which at least one NAL unit is assigned shall be present.4) In one example, it is specified that a DSCV SEI message with dscv_id equal to a particular value dscIdVal shall be present in the last AU in decoding order in the verification period for dsci id equal to dscIdVal. a. Alternatively, in one example, it is specified that a DSCV SEI message identified by dscv_id and dscv_vss_id shall be present in the last AU in decoding order that is in the verification period for dsci_id equal to dscv_id and contains at least one verification NAL unit of the verification substream with verification substream ID equal to dscv vss id.5) In one example, it is specified that, when an AU contains a DSCS SEI message with dscs_id equal to dscIdA and dscs_vss_id equal to vssIdA and a DSCV SEI message with dscv_id equal to dscIdA and dscv_vss_id equal to vssIdA, the DSCS SEI message shall precede the DSCV SEI message in decoding order.6) In one example, it is specified that, within the current verification period, there shall be no verification NAL unit of the verification sub stream with verification substream ID equal to dscv vss id succeeding the current PU (i.e., the PU containing the current DSCV SEI message) in decoding order.7) In one example, it is specified that all DSCV SEI messages having a particular value of dscv id and a particular value of dscv vss id in a verification period for the particular value of dsci id equal to dscv id shall have die same content.6. Embodiments

[0102] Below are some example embodiments for the aspects summarized in section 5. Most relevant parts that have been added or modified are shown with double braces {{ }}, and some of the deleted parts are shown with triple brackets [[[ ]]]. There may be some other changes that are editorial in nature and thus not highlighted.6.1 Embodiment 1

[0103] In clause 3 of the VSE1 spec, replace the definition of intra random access point (TRAP) picture with the following:

[0104] intra random access point (1RAP) picture: A coded picture starting from which all pictures m the same layer in both decoding order and output order can be decoded without first decoding any picture in the same layer earlier in decoding order in the coded video bitstream [ {. and starting from the coded picture for all pictures in the same layer in both decoding order and output order the cropped decoded pictures arc fully correct.}}

[0105] In clause 3 of the VSEI spec, add the following definitions:

[0106] {{gradual decoding refresh (GDR) picture: A coded picture starting from which all pictures in the same layer in both decoding order and output order can be decoded without first decoding any picture in the same layer earlier in decoding order in the coded video bitstream, and starting from a subsequent picture in decoding order for all pictures in the same layer in both decoding order and output order the cropped decoded pictures are fully correct. }}[ 01071 { {gradual decoding refresh (GDR) AU: An AU in which each coded picture is a GDR picture. } } 8.38 Digitally signed content SEI messages8.38.1 General

[0108] The digitally signed content initialization (DSCI) SEI message, digitally signed content selection (DSCS) SEI message, and digitally signed content verification (DSCV) SEI message provide a mechanism for verifying that the coded video has been produced by a content provider that identifies itself via the digital certificate that is referenced in the DSCI SEI message. These three SEI messages are collectively referred to as the digitally signed content (DSC) SEI messages.

[0109] Use of the DSC SEI messages requires the definition of the following:- A list of non-VCL NAL unit types NonVclDigitallySignedNalUnitsList.- For a VCL NAL unit, a layer identifier, denoted herein by Layerld.- For a VCL NAL unit, a temporal sublayer identifier, denoted herein by SubLrId.- A variable indicating the maximum number of temporal sublayers in the CVS, denoted herein by MaxNumSubLrs.

[0110] A verification period for a particular dsci_id value dscIdVal is defined as the sequence of AUs that is in a CVS and consists of, in decoding order, of an AU containing a DSCI SEI message with dsci_id equal to dscIdVal, followed by zero or more AUs that do not contain a DSCI SEI message with dsci_id equal to dscIdVal, including all subsequent AUs up to but not including any subsequence AU that does contain a DSCI SEI message with dsci_id equal to dscIdVal.

[0111] A verification NAL unit is defined as a NAL unit that is either a non-VCL NAL unit with NAL unit type among the values in NonVclDigitallySignedNalUnitsList or a VCL NAL unit.

[0112] A verification substream for a particular dsci_id value dscIdVal is defined as all the verification NAL units associated with dscs id equal to dscIdVal and a particular dscs vss id value in a verification period for the particular dsci_id value.

[0113] Within a verification period for a particular dsci id value dscIdVal, the DSCI SEI message with dsci_id equal to dscIdVal and a DSCS SEI message with dscs_id equal to dscIdVal are said to be associated with each other, and the DSCI SEI message with dsci_id equal to dscIdVal and a DSCV SEI message with dscv_id equal to dscIdVal are said to be associated with each other.8.38.2 Digitally signed content initialization SEI message8.38.2.1 Digitally signed content initialization SEI message syntaxdigitally_signed_content_initialization( payloadSize ) { Descriptor dsci_id u(8) dsci_hash_method_type u(8) dsci_key_source_uri st(v) dsci_num_vsss_minus1 ue(v) ... u(8) dsci_key_retrieval_mode_idc ue(v) if( dsci_key_retrieval_mode_idc = = 1 ) {dsci_use_key_register_idx_flag u(l) if( dsci_use_key_register_idx_flag )dsci_key_register_idx ue(v) }dsci_content_uuid_present_flag u(l)if( dsci content uuid_present flag )dsci_content_uuid u(128) }8.38.2.2 Digitally signed content initialization SEI message semantics

[0114] The DSCI SEI message with a particular dsci id value provides information about the secure hash algorithm used for calculating message digests, which are used together with the digital signatures present in the associated DSCV SEI messages to verify the trustworthiness of all verification substreams in the current verification period (i.e., the verification period containing the current DSCI SEI message. It further provides information about the digital signature algorithm used and the public key of the content provider. The DSCI SEI message may provide the public key either by providing an URI that identifies a trust record, as specified in 1SO / 1EC 21617-1, that contains the certificate or by providing an URI that directly identifies the certificate.

[0115] When a DSCI SEI message with a particular dsci_id value dsddVal is present in any AU of a CVS, all of the following shall be true:- {{A DSCI SEI message with dsci_id equal to dsddVal shall be present in each IRAP or GDRAU in the CVS.}}- The DSCI SEI message in an AU shall precede all verification NAL units in the AU.- There shall be at most one DSCI SEI message having a particular value of dsci_id in an AU.

[0116] The DSCI SEI message with a particular dsci id value applies to all AUs in the current verification period.

[0117] dsci id contains an identifying number that may be used to identify a mechanism for verifying that the coded video represented by the current verification period has been produced by the content provider identified by the DSCI SEI message.

[0118] dsci_num_vsss_minus1 plus 1 indicates the number of verification substreams for which message digests are calculated and signatures may be present in the associated DSCV SEI messages. The value of dsci_num_vsss_minus1 shall be in the range of 0 to 255, inclusive.

[0119] The variable NumVerificationSubstreams is derived as:NumVerificationSubstreams = dsci_num_vsss_minus1 + 1.8.38.3 Digitally signed content selection SEI message8.38.3.1 Digitally signed content selection SEI message syntaxdigitally_signed_content_selection( payloadSize ) { Descriptor dscs_id u(8) dscs_vss_id u(8) }8.38.3.2 Digitally signed content selection SEI message semantics

[0120] The digitally signed content selection SEI message provides a mechanism for associating verification NAL units in a PU with one of the verification substreams indicated in a DSCI SEI message with dsci_id equal to dscs_id.

[0121] When a DSCS SEI message is present in any PU, it shall precede all verification inclusion NAL units in the PU.

[0122] dscs_id contains an identifying number that may be used to identify a mechanism for verifying that the coded video represented by the current verification period (i.e., the verification period for dsci_id equal to dscs_id containing the current DSCS SEI message) has been produced by the content provider indicated by the associated DSCI SEI message.

[0123] dscs_vss_id specifies the verification substream ID of the verification substream to which the verification NAL units in the current PU are assigned to.8.38.4 Digitally signed content verification SEI message8.38.4.1 Digitally signed content verification SEI message syntaxdigitally _signed_content_verification( payloadSize ) { Descriptor dscv id u(8) dscv_vss_id u(8) dscv_signature_length_in_octets_minus1 u(16) dscv_signature u(v) }8.38.4.2 Digitally signed content verification SEI message semantics[01241 The DSCV SEI message provides a mechanism for verifying the digital signature of a verification substream indicated in a DSCI SEI message identified by dsci id equal to dscv id.

[0125] Within a verification period for a particular dsci id value, a DSCV SEI message for each of the verification substreams for the particular dsci_id value to which at least one NAL unit is assigned shall be present.

[0126] When a CVS does not contain a DSCI SEI message with a particular dsci id value, the CVS shall not contain DSCV SEI messages with dscv_id equal to the particular dsci_id value.

[0127] [[[When an AU contains both a digitally signed content initialization SEI message identified by dsci_id equal to dscv_id and a digitally signed content verification SEI message identified by dsci_id equal to dscv id, the digitally signed content initialization SEI message shall precede the digitally signed content verification SEI message.]]]

[0128] [[[When a PU contains both a digitally signed content selection SEI message identified by dsci_id equal to dscv_id and a digitally signed content verification SEI message identified by dsci_id equal to dscv_id, the digitally signed content selection SEI message shall precede the digitally signed content verification SEI message ]]]

[0129] { {When an AU contains a DSCS SEI message with dscs id equal to dsddA and dscs vss id equal to vssIdA and a DSCV SEI message with dscv_id equal to dscIdA and dscv_vss_id equal to vssIdA, the DSCS SEI message shall precede the DSCV SEI message in decoding order.}}

[0130] {{Within the current verification period (i.e., the verification period for dsci_id equal to dscv_id containing the current DSCV SEI message), there shall be no verification NAL unit of the verification substream with verification substream ID equal to dscv_vss_id succeeding the current PU (i.e., the PU containing the current DSCV SEI message) in decoding order. }}

[0131] { {All DSCV SEI messages having a particular value of dscv_id and a particular value of dscv_vss_id in a verification period for the particular value of dsci_id equal to dscv_id shall have the same content. }}

[0132] dscv_id contains an identifying number that may be used to identify a mechanism for verifying that the coded video represented by the current verification period has been produced by the content provider indicated by the associated DSCI SEI message.

[0133] dscv_vss_id specifies the verification substream ID of the verification substream to which the SEI message applies.7. References[1] Rec. ITU-T H.265 | ISO / IEC 23008-2, “High efficiency video coding”.[2] Rec. ITU-T H.266 | ISO / IEC 23090-3, “Versatile Video Coding”.[3] Rec. ITU-T Rec. H.274 | ISO / IEC 23002-7, “Versatile Supplemental Enhancement Information Messages for Coded VideoBitstreams”.[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 5),” JVET output document JVET-AK2006- v2, publicly available online herein: https: / / www.jvet-experts.org / doc_end_user / documents / 37_Geneva / wgl lZJVET-AK2006-v2.zip.

[0134] 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.

[0135] 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 may 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 cither 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 may be used by a component 4008 for generating pixel values or display able video that is sent to a display interface 4010. The process of generating user-viewable video from die bitstream representation is sometimes called video decompression. Furthermore, while certain video processing operations are referred to as “coding” operations or tools, it will be appreciated that die 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.

[0136] Examples of a peripheral bus interface or a display interface may include universal serial bus (USB) or high definition multimedia interface (HDM1) 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 arc capable of performing digital data processing and / or video display.

[0137] 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 for storing data and code used for implementing the methods and techniques described herein. The video processing circuitry' 4106 may be used to implement, in hardware circuitry, some techniques described in the present disclosure. In some embodmients, the video processing circuitry 4106 may be at least partly' included in the processor 4102, e.g., a graphics co-processor.

[0138] FIG. 3 is a flowchart for an example method 4200 of video processing. The method 4200 determines that, within a verification period for a particular digitally' signed content initialization (DSCI) identifier (dsci id) value (dseldVal), a digitally signed content verification (DSCV) supplemental enhancement information (SEI) message for each of a plurality of verification substreams for the particular dsci_id value (dscIdVal) to which at least one network abstraction layer (NAL) unit is assigned shall be present at step 4202. A conversion is performed between a visual media data and a bitstream based on the DSCV SEI message at step 4204. The conversion may include encoding at an encoder, decoding at a decoder, or combinations thereof.

[0139] 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.

[0140] 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.

[0141] 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 sy ntax structures. I / O interface 4316 may include a modulator / demodulator (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.

[0142] 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 amodem. 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 with the destination device 4320, or may be external to destination device 4320, which can be configured to interface with an external display device.

[0143] 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.

[0144] 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 ofthe techniques 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 techniques described in this disclosure.

[0145] 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, 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.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] 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 thatindicates the reference picture in list 0 or list 1 that contains the reference video block and a motion vector that indicates a spatial displacement between 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.

[0153] In other examples, motion estimation unit 4404 may perform 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.

[0154] 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 determine that the motion information of the current video block is sufficiently similar to the motion information of a neighboring video block.

[0155] 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.

[0156] In another example, motion estimation unit 4404 may identify, in a syntax 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 determine the motion vector of the current video block.

[0157] 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.

[0158] 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 generateprediction data for the current video block based on decoded samples of other video blocks in the same picture. The prediction data for the current video block may include a predicted video block and various syntax elements.

[0159] 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.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] 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.

[0164] After reconstruction unit 4412 reconstructs the video block, the loop filtering operation may be performed to reduce video blocking artifacts in the video block.

[0165] Entropy encoding unit 4414 m ay 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.

[0166] 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.

[0167] 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 some1examples, perform a decoding pass generally reciprocal to the encoding pass described with respect to video encoder 4400.101681 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.

[0169] 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.

[0170] 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.

[0171] Motion compensation unit 4502 may use some of the syntax information to determine sizes of blocks used to encode frame(s) and / or slice(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.

[0172] 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.

[0173] 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 arc 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.

[0174] FIG. 7 is a schematic diagram of an example encoder 4600. The encoder 4600 is suitable for implementing the techniques of VVC. The encoder 4600 includes three in-loop filters, namely a deblocking filter (DF) 4602, a sample adaptive offset (SAO) 4604, and an adaptive loop filter (ALF) 4606. Unlike the DF 4602, which uses predefined filters, the SAG 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 theoffsets 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.

[0175] 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 die 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.

[0176] A listing of solutions preferred by some examples is provided next.

[0177] The following solutions show examples of techniques discussed herein.

[0178] 1. A method for processing media data comprising: determining when a digitally signed content initialization (DSCI) supplemental enhancement information (SEI) message with a particular DSCI identifier (dsci id) value (dscIdVal) is present in any access unit (AU) of a coded video sequence (CVS), a DSCI SEI message with dsci_id equal to dscIdVal shall be present in each intra random access point (IRAP) or gradual decoding refresh (GDR) AU (GDRAU) in the CVS: and performing a conversion between a visual media data and a bitstream based on the DSCI SEI message.

[0179] 2. The method of solution 1, wherein a GDR picture is defined as a coded picture starting from which all pictures in the same layer in both decoding order and output order can be decoded without first decoding any picture in the same layer earlier in decoding order in the coded video bitstream, and starting from a subsequent picture in decoding order for all pictures in the same layer in both decoding order and output order the cropped decoded pictures are fully correct.

[0180] 3. The method of any of solutions 1-2, wherein a GDRAU is defined as an AU in which each coded picture is a GDR picture.

[0181] 4. The method of any of solutions 1-3, wherein all DSCI SEI messages with a particular value of dsci id within a CVS shall have the same content.

[0182] 5. The method of any of solutions 1-4, wherein within a verification period for a particular dsci_id value, one and only one digitally signed content verification (DSCV) SEI message for each of the verification substreams for the particular dsci id value to which at least one NAL unit is assigned shall be present.

[0183] 6. The method of any of solutions 1-5, wherein a DSCV SEI message with dscv_id equal to a particular value dscldVal shall be present in the last AU in decoding order in the verification period for dsci_id equal to dscldVal.

[0184] 7. The method of any of solutions 1-6, wherein a DSCV SEI message identified by dsev id and dscv_vss_id shall be present in the last AU in decoding order that is in the verification period for dsci_id equal to dscv_id and contains at least one verification NAL unit of the verification substream with verification substream ID equal to dscv vss id.

[0185] 8. The method of any of solutions 1-7, wherein when an AU contains a digitally signed content selection (DSCS) SEI message with dscs_id equal to dscldA and dscs_vss_id equal to vssldA and a DSCV SEI message with dscv_id equal to dscIdA and dscv_vss_id equal to vssIdA, the DSCS SEI message shall precede the DSCV SEI message in decoding order.

[0186] 9. The method of any of solutions 1-8, wherein within the current verification period, there shall be no verification network abstraction layer (NAL) unit of the verification substream with verification substream ID equal to dscv_vss_id succeeding the current PU in decoding order, wherein the current PU is the PU containing the current DSCV SEI message.

[0187] 10. The method of any of solutions 1-9, wherein all DSCV SEI messages having a particular value of dscv_id and a particular value of dscv_vss_id in a verification period for the particular value of dsci_id equal to dscv_id shall have the same content.

[0188] 11. The method of any of solutions 1-10, wherein the conversion includes encoding the visual media data into the bitstream.

[0189] 12. The method of any of solutions 1-10, wherein the conversion includes decoding the visual media data from the bitstream.

[0190] 13. 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 solutions 1-12.

[0191] 14. 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 solutions 1-12.

[0192] 15. 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 when a digitally signed content initialization (DSCI) supplemental enhancement information (SEI) message with a particular DSCI identifier (dsci_id) value (dscIdVal) is present in any access unit (AU) of a coded video sequence (CVS), a DSCI SEI message with dsci_id equal to dscldVal shall be present in each intra random accesspoint (IRAP) or gradual decoding refresh (GDR) AU (GDRAU) in the CVS; and generating a bitstream based on the determining.|0193] 16. A method for storing bitstream of a video comprising: determining when a digitally signed content initialization (DSCI) supplemental enhancement information (SEI) message with a particular DSCI identifier (dsci_id) value (dsddVal) is present in any access unit (AU) of a coded video sequence (CVS), a DSCI SEI message with dsci id equal to dsddVal shall be present in each intra random access point (IRAP) or gradual decoding refresh (GDR) AU (GDRAU) in the CVS; generating a bitstream based on the determining; and storing the bitstream in a non-transitory computer-readable recording medium.

[0194] 17. A method, apparatus, or sy stem described in the present disclosure.

[0195] In the solutions described herein, an encoder may conform to the fonnat rule by producing a coded representation according to the fonnat rule. In the solutions described herein, a decoder may use the fonnat 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.

[0196] 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 that 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.

[0197] 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 managementsystem, 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.

[0198] A computer program (also known as a program, software, 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.

[0199] 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, an field programmable gate array (FPGA) or an application specific integrated circuit (ASIC).

[0200] Processors suitable for the execution of a computer program include, by way 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 optical 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.

[0201] While the present disclosure contains many' specifics, these should not be construed as limitations on the scope of any subject matter or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular techniques. 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 beimplemented 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.

[0202] Similarly, while 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 shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Moreover, 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.

[0203] 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.

[0204] A first component is directly coupled to a second component when there are no intervening 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 when there are intervening components other than a line, a trace, or another medium between 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.

[0205] 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.

[0206] In addition, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or 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

CLAIMSWhat is claimed is:

1. A method for processing media data, comprising:determining that, within a verification period for a particular digitally signed content initialization (DSCI) identifier (dsci_id) value (dscIdVal), a digitally signed content verification (DSCV) supplemental enhancement information (SEI) message for each of a plurality of verification substreams for the particular dsci_id value (dscIdVal) to which at least one network abstraction layer (NAL) unit is assigned shall be present; and performing a conversion between a visual media data and a bitstream based on the DSCV SEI message.

2. The method of claim 1, wherein there is one and only one DSCV SEI message for each of the plurality of verification substreams for the particular dsci id value (dscIdVal) to which the at least one network abstraction layer (NAL) unit is assigned.

3. The method of any of claims 1-2, wherein, within the current verification period, there shall be no verification substream member NAL unit of a verification substream with a verification substream identifier (ID) equal to a DSCV SEI verification substream identifier (ID) succeeding a current prediction unit (PU) in decoding order.

4. The method of claim 3, wherein the current PU comprises a PU containing a current DSCV SEI message.

5. The method of any of claims 1-4, wherein the DSCV SEI message provides a mechanism for verifying a digital signature of a verification substream indicated in the DSCI SEI message identified by the DSCI identifier (dsci_id) equal to a DSCV identifier (dscv_id).

6. The method of any of claims 1-5, wherein, when a coded video sequence (CVS) does not contain a DSCI SEI message, the CVS shall not contain a DSCV SEI message.

7. The method of claim 6, wherein, when the CVS does not contain a DSCI SEI message with the particular DSCI identifier (dsci id) value (dscIdVal), the CVS shall not contain a DSCV SEI message with the DSCI identifier (dsci id) equal to the particular DSCI identifier (dsci id) value (dscIdVal).

8. The method of any of claims 1-7, wherein, when an access unit (AU) contains both a DSCI SEI message and a DSCV SEI message, the DSCI SEI message shall precede the DSCV SEI message.

9. The method of claim 8, wherein, when the AU contains both a DSCI SEI message the particular DSCI identifier (dsci id) value (dscIdVal) and a DSCV SEI message with a DSCV identifier (dscv id) equal to the particular DSCI identifier (dsci id) value (dscIdVal), the DSCI SEI message shall precede the DSCV SEI message.

10. The method of any of claims 1-9, wherein, when a prediction unit (PU) contains both a digitally signed content selection (DSCS) SEI message and a DSCV SEI message, the DSCS SEI message shall precede the DSCV SEI message.

11. The method of any of claims 1-10, wherein the DSCV identifier (dscv_id) contains an identifying number of a verification system that may be applied for verifying that coded video has been produced by a content provider indicated by an associated DSCV SEI message.

12. The method of any of claims 1-11, wherein a DSCV verification substream identifier (dscv verification substream id) specifies a verification substream ID of a verification substream to which the DSCV SEI message applies.

13. The method of claim 12, wherein a DSCV signature (dscv_signature) contains a digital signature for a verification substream indicated by the DSCV verification substream identifier (dscv verification substream id).

14. The method of any of claims 1 -13, wherein the DSCV identifier (dscv id) is coded as an 8-bit unsigned integer (u(8)).

15. The method of any of claims 1-14, wherein the DSCV identifier (dscv id) is a first syntax element coded in the DSCV SEI message.

16. The method of any of claims 1-15, wherein the conversion includes encoding the visual media data into the bitstream.

17. The method of any of claims 1-15, wherein the conversion includes decoding the visual media data from the bitstream.

18. 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 1-17.

19. 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 1-17.

20. 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, within a verification period for a particular digitally signed content initialization (DSCI) identifier (dsci_id) value (dsddVal), a digitally signed content verification (DSCV) supplemental enhancement information (SEI) message for each of a plurality of verification substreams for the particular dsci id value (dscIdVal) to which at least one network abstraction layer (NAL) unit is assigned shall be present; and generating a bitstream based on the determination.

21. A method for storing a bitstream of a video, comprising:determining that, within a verification period for a particular digitally signed content initialization (DSCI) identifier (dsci_id) value (dscIdVal), a digitally signed content verification (DSCV) supplemental enhancement information (SEI) message for each of a plurality of verification substreams for the particular dsci_id value (dscIdVal) to which at least one network abstraction layer (NAL) unit is assigned shall be present;generating the bitstream based on the determination; andstoring the bitstream in a non-transitory computer-readable recording medium.

22. A method, apparatus, or system described in the present disclosure.

Images