Neural network post-processing filter purpose with picture rate upsampling

Abstract

A mechanism for processing video data is disclosed. The mechanism includes determining a neural network post-processing filter (NNPF) purpose based on a neural network post-processing filter characteristic (NNPFC) supplemental enhancement information (SEI) message. A conversion between the visual media data and the bitstream is performed based on the NNPF destination. Multiple input pictures are used for NNPF purposes, and NNPF can selectively generate output pictures for some input picture (s) rather than for other input picture (s).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the rights of International Patent Application No. PCT / CN2023 / 072367 filed on January 16, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the generation, storage, and use of digital audio-visual media information in file format. Background Art

[0004] Digital video consumes the largest amount of bandwidth used for the Internet and other digital communications 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 of the Invention

[0005] The first aspect relates to a method for processing video data, comprising: determining a neural network post-processing filter (NNPF) purpose based on a neural network post-processing filter characteristic (NNPFC) supplemental enhancement information (SEI) message; and performing conversion between visual media data and a bitstream based on the NNPF purpose.

[0006] A second aspect relates to an apparatus for processing video data, comprising: a processor; and a non-transitory memory having instructions thereon, wherein the instructions, when executed by the processor, cause the processor to perform any one of the preceding aspects.

[0007] A third aspect relates to a non-transitory computer-readable medium, comprising a computer program product for use with a video codec device, the computer program product comprising computer-executable instructions stored on the non-transitory computer-readable medium, so that when executed by a processor, the video codec device performs the method of any one of the preceding aspects.

[0008] A fourth aspect relates to a non-transitory computer-readable recording medium storing a bitstream of a video generated by a method performed by a video processing device, wherein the method includes: determining a neural network post-processing filter (NNPF) purpose based on a neural network post-processing filter characteristic (NNPFC) supplemental enhancement information (SEI) message; and generating a bitstream based on the determination.

[0009] A fifth aspect relates to a method for storing a bitstream of a video, comprising: determining a neural network post-processing filter (NNPF) purpose based on a neural network post-processing filter characteristic (NNPFC) supplemental enhancement information (SEI) message; generating a bitstream based on the determination; and storing the bitstream in a non-temporary computer-readable recording medium.

[0010] The sixth aspect relates to the method, device or system described in the present disclosure.

[0011] For purposes of clarity, any of the foregoing embodiments may be combined with any one or more of the other foregoing embodiments to create new embodiments within the scope of the present disclosure.

[0012] These and other features will be more clearly understood from the following detailed description with reference to the accompanying drawings and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in conjunction with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.

[0014] Figure 1 An example of deriving a luma channel from a luminance component is shown.

[0015] Figure 2 is a block diagram illustrating an example video processing system.

[0016] Figure 3 is a block diagram of an example video processing device.

[0017] Figure 4 is a flow chart of an example method of video processing.

[0018] Figure 5 is a block diagram illustrating an example video encoding and decoding system.

[0019] Figure 6 is a block diagram illustrating an example encoder.

[0020] Figure 7 is a block diagram illustrating an example decoder.

[0021] Figure 8 is a schematic diagram of an example encoder. DETAILED DESCRIPTION

[0022] It should be understood at the outset that although illustrative implementations of one or more embodiments are provided below, the disclosed systems and / or methods may be implemented using any number of technologies, whether currently known or yet to be developed. The present disclosure should in no way be limited to the illustrative implementations, drawings, and examples shown below, including the exemplary designs and implementations shown and described herein, but may be modified within the scope of the appended claims and their full scope of equivalents.

[0023] The section headings are used in this disclosure for ease of understanding and not to limit the applicability of the techniques and embodiments disclosed in each section to only that section. In addition, the use of H.266 terminology in some descriptions is solely for ease of understanding and not for limiting the scope of the disclosed embodiments. Therefore, the embodiments described herein are also applicable to other video codec protocols and designs. In this disclosure, editorial changes to text are shown relative to the Versatile Video Codec (VVC) specification and / or the International Organization for Standardization (ISO) Base Media File Format (ISOBMFF) standard by indicating deleted text in bold italics and adding text in bold.

[0024] 1. Preliminary Discussion

[0025] The present disclosure relates to image / video coding techniques. Specifically, the present disclosure relates to the definition and signaling of neural network post-processing filter (NNPF) objectives with picture rate upsampling and other types of upsampling, more efficient signaling of the number of interpolated pictures, the order of multiple types of upsampling, and the number of input pictures for any NNPF objective. These ideas can be applied alone or in various combinations to video bitstreams encoded and decoded by any codec (e.g., the Versatile Video Codec (VVC) standard and / or the Versatile Supplemental Enhancement Information (SEI) message (VSEI) standard for encoding and decoding video bitstreams).

[0026] 2. Abbreviation

[0027] The following abbreviations may be used in the present disclosure: adaptation parameter set (APS), access unit (AU), codec layer video sequence (CLVS), codec layer video sequence start (CLVSS), cyclic redundancy check (CRC), codec video sequence (CVS), finite impulse response (FIR), intra-frame random access point (IRAP), network abstraction layer (NAL), picture parameter set (PPS), picture unit (PU), random access skipped leading (RASL) picture, supplemental enhancement information (SEI), step-by-step temporal sublayer access (STSA), video codec layer (VCL), versatile supplemental enhancement information (VSEI) described in Rec. ITU-T H.274 | ISO / IEC 23002-7, video usability information (VUI), versatile video codec (VVC) described in Rec. ITU-T H.266 | ISO / IEC 23090-3.

[0028] 3. Further Discussion

[0029] 3.1 Video Codec Standards

[0030] Video codec standards have evolved primarily through the development of standards within the International Telecommunication Union (ITU) Telecommunication Standardization Sector (ITU-T) and the International Organization for Standardization (ISO) / International Electrotechnical Commission (IEC). ITU-T produced the H.261 and H.263 standards, ISO / IEC produced the Moving Picture Experts Group (MPEG)-1 and MPEG-4 Vision, and the two organizations jointly produced the H.262 / MPEG-2 Video standard, the H.264 / MPEG-4 Advanced Video Coding (AVC) standard, and the H.265 / High Efficiency Video Coding (HEVC) standard [1]. Starting with H.262, video codec standards are based on a hybrid video codec structure that utilizes temporal prediction plus transform coding. To explore video codec technologies beyond High Efficiency Video Coding (HEVC), the Video Coding Experts Group (VCEG) and the Moving Picture Experts Group (MPEG) established the Joint Video Exploration Team (JVET). Furthermore, JVET adopted a variety of methods and incorporated them into a reference software called the Joint Exploration Model (JEM) [2]. JVET was later renamed the Joint Video Experts Team (JVET) when the Versatile Video Codec (VVC) project was officially launched. VVC[3] is a codec standard that aims to reduce bitrate by 50% compared to HEVC.

[0031] The Versatile Video Codec (VVC) standard (ITU-T H.266 | ISO / IEC 23090-3) [3] and the associated Versatile Supplementary Enhancement Information (VSEI) standard for codec video bitstreams (ITU-T H.274 | ISO / IEC 23002-7) [4] are designed for the widest range of applications, including simple uses such as television broadcasting, video conferencing, or playback from storage media, as well as more advanced use cases such as adaptive bitrate streaming, video region extraction, combining and merging of content from multiple codec video bitstreams, multi-view video, scalable layered codecs, and viewport-adaptive 360° immersive media.

[0032] The Essential Video Codec (EVC) standard (ISO / IEC 23094-1) is another video codec standard developed by MPEG.

[0033] 3.2 SEI messages in general and in VVC and VSEI

[0034] SEI messages assist processes related to decoding, display, or other purposes. However, SEI messages are not required to construct luma or chroma samples through the decoding process. Standard-compliant decoders do not need to process this information to achieve output order consistency. Some SEI messages are required to check bitstream consistency and output timing decoder consistency. Other SEI messages are not required to check bitstream consistency.

[0035] Annex D of VVC specifies the syntax and semantics of the SEI message payload of some SEI messages, and specifies the use of SEI messages and VUI parameters whose syntax and semantics are specified in ITU-T H.274 | ISO / IEC 23002-7.

[0036] 3.3 Signaling of Neural Network Post-Processing Filters

[0037] WG 05 output documents N0158 [5] and JVET-AB2006 [6] include specifications for two SEI messages for signaling of neural network post-processing filters, as shown below.

[0038] 8.28 Neural Network Post-Processing Filter Characteristics SEI Message

[0039] 8.28.1 Neural Network Post-Processing Filter Characteristics SEI Message Syntax

[0040]

[0041]

[0042]

[0043] 8.28.2 Neural Network Post-Processing Filter Characteristics SEI Message Semantics

[0044] The Neural Network Post-Processing Filter Characteristics (NNPFC) SEI message specifies a neural network that can be used as a post-processing filter. The Activate Utilize Neural Network Post-Processing Filter SEI message indicates the use of a specified post-processing filter for a particular picture.

[0045] Using this SEI message requires defining the following variables:

[0046] – The width and height of the cropped decoded output picture, in units of luma samples, denoted as CroppedWidth and CroppedHeight in this document.

[0047] – The luma sample array CroppedYPic[idx] and the chroma sample arrays CroppedCbPic[idx] and CroppedCrPic[idx] (when present) of the cropped decoded output picture used as input to the post-processing filter, where idx ranges from 0 to numInputPics-1 (inclusive).

[0048] – The bit depth BitDepthY of the luma sample array of the cropped decoded output picture.

[0049] – The bit depth BitDepthC of the chroma sample array (if any) of the cropped decoded output picture.

[0050] – The chroma format indicator, denoted herein as ChromaFormatIdc, as described in sub-entry 7.3.

[0051] – When nnpfc_auxiliary_inp_idc is equal to 1, the filter strength control value StrengthControlVal must be a real number in the range 0 to 1 (inclusive).

[0052] The variables SubWidthC and SubHeightC are derived from ChromaFormatIdc as specified in Table 2. NOTE 1 – More than one NNPFC SEI message may be present for the same picture. When more than one NNPFC SEI message with different values ​​of nnpfc_id is present or activated for the same picture, they may have the same or different values ​​of nnpfc_purpose and nnpfc_mode_idc.

[0053] nnpfc_id includes an identification number that can be used to identify the post-processing filter. The value of nnpfc_id must be in the range of 0 to 232-2 (inclusive). The values ​​of nnpfc_id from 256 to 511 (inclusive) and from 231 to 232-2 (inclusive) are reserved for future use by ITU-T | ISO / IEC. A decoder conforming to this version of this document must ignore the SEI message when it encounters an NNPFC SEI message with a nnpfc_id in the range of 256 to 511 (inclusive) or in the range of 231 to 232-2 (inclusive).

[0054] When the NNPFC SEI message is the first NNPFC SEI message in decoding order with a particular nnpfc_id value within the current CLVS, the following applies:

[0055] – This SEI message specifies the basic post-processing filters.

[0056] – This SEI message applies to the current decoded picture and all subsequent decoded pictures of the current layer, in output order, until the end of the current CLVS.

[0057] When an NNPFC SEI message is a repetition of a previous NNPFC SEI message in decoding order in the current CLVS, subsequent semantics apply as if the SEI message is the only NNPFC SEI message with the same content within the current CLVS.

[0058] When the NNPFC SEI message is not the first NNPFC SEI message in decoding order with a particular nnpfc_id value within the current CLVS, the following applies:

[0059] – This SEI message defines updates relative to the preceding base post-processing filter in decoding order with the same nnpfc_id value.

[0060] – This SEI message applies to the current decoded picture and all subsequent decoded pictures of the current layer, in output order, until the end of the current CLVS or the next NNPFC SEI message with this specific nnpfc_id value within the current CLVS (in output order).

[0061] nnpfc_mode_idc equal to 0 indicates that the SEI message includes an ISO / IEC 15938-17 bitstream that specifies a base post-processing filter or an update relative to a base post-processing filter with the same nnpfc_id value.

[0062] When the NNPFC SEI message is the first NNPFC SEI message in decoding order with a particular nnpfc_id value within the current CLVS, nnpfc_mode_idc equal to 1 specifies that the base post-processing filter associated with the nnpfc_id value is a neural network identified by the URI indicated by nnpfc_uri using the format identified by the tag URI nnpfc_tag_uri.

[0063] When the NNPFC SEI message is not the first NNPFC SEI message in decoding order with a particular nnpfc_id value within the current CLVS, nnpfc_mode_idc equal to 1 specifies that updates relative to the base post-processing filter with the same nnpfc_id value are defined by the URI indicated by nnpfc_uri using the format identified by the tag URI nnpfc_tag_uri.

[0064] In bitstreams conforming to this version of this document, the value of nnpfc_mode_idc MUST be in the range 0 to 1, inclusive. Values ​​of nnpfc_mode_idc from 2 to 255, inclusive, are reserved for future use by ITU-T | ISO / IEC and MUST NOT be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document MUST ignore NNPFC SEI messages with nnpfc_mode_idc in the range 2 to 255, inclusive. Values ​​of nnpfc_mode_idc greater than 255 MUST NOT be present in bitstreams conforming to this version of this document and are not reserved for future use.

[0065] When this SEI message is the first NNPFC SEI message in decoding order with a specific nnpfc_id value within the current CLVS, the post-processing filter PostProcessingFilter() is assigned to be the same as the basic post-processing filter.

[0066] When this SEI message is not the first NNPFC SEI message in decoding order with a particular nnpfc_id value within the current CLVS, the post-processing filter PostProcessingFilter() is obtained by applying the updates defined by this SEI message to the base post-processing filter.

[0067] Updates are not cumulative, but each update is applied to the base post-processing filter, which is the post-processing filter specified by the first NNPFC SEI message in decoding order with a particular nnpfc_id value within the current CLVS.

[0068] nnpfc_reserved_zero_bit_a MUST be equal to 0 in bitstreams conforming to this version of this document. A decoder MUST ignore NNPFC SEI messages with nnpfc_reserved_zero_bit_a not equal to 0.

[0069] nnpfc_tag_uri includes a tag URI with syntax and semantics as specified by IETF RFC 4151 that identifies the format and related information of a neural network used as a base post-processing filter or an update relative to the base post-processing filter with the same nnpfc_id value specified by nnpfc_uri.

[0070] NOTE 2 – nnpfc_tag_uri enables the format of neural network data specified by nnrpf_uri to be uniquely identified without the need for a central registration authority.

[0071] nnpfc_tag_uri equal to "tag:iso.org,2023:15938-17" indicates that the neural network data identified by nnpfc_uri complies with ISO / IEC 15938-17.

[0072] nnpfc_uri comprises a URI having syntax and semantics as specified by IETF Internet Standard 66 that identifies a neural network used as a base post-processing filter or an update relative to a base post-processing filter having the same nnpfc_id value.

[0073] nnpfc_formatting_and_purpose_flag equal to 1 specifies that syntax elements related to filter purpose, input format, output format and complexity are present. nnpfc_formatting_and_purpose_flag equal to 0 specifies that syntax elements related to filter purpose, input format, output format and complexity are not present.

[0074] When this SEI message is the first NNPFC SEI message in decoding order with a particular nnpfc_id value within the current CLVS, nnpfc_formatting_and_purpose_flag must be equal to 1. When this SEI message is not the first NNPFC SEI message in decoding order with a particular nnpfc_id value within the current CLVS, nnpfc_formatting_and_purpose_flag must be equal to 0.

[0075] nnpfc_purpose indicates the purpose of the post-processing filter, as specified in Table 20.

[0076] In bitstreams conforming to this version of this document, the value of nnpfc_purpose shall be in the range of 0 to 5, inclusive. Values ​​of nnpfc_purpose from 6 to 1023, inclusive, are reserved for future use by ITU-T|ISO / IEC and shall not be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document shall ignore NNPFC SEI messages with nnpfc_purpose in the range of 6 to 1203, inclusive. Values ​​of nnpfc_purpose greater than 1023 shall not be present in bitstreams conforming to this version of this document and are not reserved for future use.

[0077] Table 20 - Definition of nnpfc_purpose

[0078]

[0079]

[0080] NOTE 3 – When the reserved value of nnpfc_purpose is used by ITU-T | ISO / IEC in the future, the syntax of this SEI message may be extended with the following syntax elements whose presence is conditional on nnpfc_purpose being equal to this value.

[0081] When SubWidthC is equal to 1 and SubHeightC is equal to 1, nnpfc_purpose must not be equal to 2 or 4.

[0082] nnpfc_out_sub_c_flag equal to 1 specifies that outSubWidthC is equal to 1 and outSubHeightC is equal to 1. nnpfc_out_sub_c_flag equal to 0 specifies that outSubWidthC is equal to 2 and outSubHeightC is equal to 1. When nnpfc_out_sub_c_flag is not present, outSubWidthC is inferred to be equal to SubWidthC, and outSubHeightC is inferred to be equal to SubHeightC. When ChromaFormatIdc is equal to 2 and nnpfc_out_sub_c_flag is present, the value of nnpfc_out_sub_c_flag must be equal to 1.

[0083] nnpfc_pic_width_in_luma_samples and nnpfc_pic_height_in_luma_samples specify the width and height, respectively, of the luma sample array of the picture produced by applying the post-processing filter identified by nnpfc_id to the cropped decoded output picture. When nnpfc_pic_width_in_luma_samples and nnpfc_pic_height_in_luma_samples are not present, they are inferred to be equal to CroppedWidth and CroppedHeight, respectively. The value of nnpfc_pic_width_in_luma_samples must be in the range of CroppedWidth to CroppedWidth*16-1 (inclusive). The value of nnpfc_pic_height_in_luma_samples must be in the range of CroppedHeight to CroppedHeight*16-1 (inclusive).

[0084] nnpfc_num_input_pics_minus2 plus 2 specifies the number of decoded output pictures used as input to the post-processing filter.

[0085] nnpfc_interpolated_pics[i] specifies the number of interpolated pictures generated by the post-processing filter between the i-th picture and the (i+1)-th picture used as input to the post-processing filter.

[0086] The variable numInputPics, which specifies the number of pictures used as input to the post-processing filter, and the variable numOutputPics, which specifies the total number of pictures produced by the post-processing filter, are derived as follows:

[0087]

[0088] nnpfc_component_last_flag is equal to 1 to indicate that the last dimension in the input tensor inputTensor of the post-processing filter and the output tensor outputTensor produced by the post-processing filter is used for the current channel. nnpfc_component_last_flag is equal to 0 to indicate that the third dimension in the input tensor inputTensor of the post-processing filter and the output tensor outputTensor produced by the post-processing filter is used for the current channel.

[0089] NOTE 4 – The first dimension in the input and output tensors is used for batch indexing, which is a practice in some neural network frameworks. Although the formulas in the semantics of this SEI message use a batch size corresponding to a batch index equal to 0, it is up to the post-processing implementation to determine the batch size used as input to the neural network inference.

[0090] Note 5 – For example, when nnpfc_inp_order_idc is equal to 3 and nnpfc_auxiliary_inp_idc is equal to 1, there are 7 channels in the input tensor, including four luma matrices, two chroma matrices, and one auxiliary input matrix. In this case, the procedure DeriveInputTensors() will derive each of these 7 channels of the input tensor one by one, and when processing a particular channel among these channels, that channel is called the current channel during the procedure.

[0091] nnpfc_inp_format_idc indicates a method for converting the sample values ​​of the cropped decoded output picture into the input values ​​of the post-processing filter. When nnpfc_inp_format_idc is equal to 0, the input values ​​of the post-processing filter are real numbers, and the functions InpY() and InpC() are defined as follows:

[0092] InpY(x)=x÷((1< <BitDepthY)-1)(77)

[0093] InpC(x)=x÷((1< <BitDepthC)-1)(78)

[0094] When nnpfc_inp_format_idc is equal to 1, the input values ​​of the post-processing filter are unsigned integers, and the functions InpY() and InpC() are defined as follows:

[0095]

[0096] The variable inpTensorBitDepth is derived from the syntax element nnpfc_inp_tensor_bitdepth_minus8 as specified below.

[0097] Values ​​of nnpfc_inp_format_idc greater than 1 are reserved for future specification by ITU-T | ISO / IEC and must not be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document must ignore NNPFC SEI messages that include reserved values ​​of nnpfc_inp_format_idc.

[0098] nnpfc_inp_tensor_bitdepth_minus8 specifies the bit depth of the luma sample values ​​in the input integer tensor plus 8. The value of inpTensorBitDepth is derived as follows:

[0099] inpTensorBitDepth=nnpfc_inp_tensor_bitdepth_minus8+8(81)

[0100] A bitstream conformance requirement is that the value of nnpfc_inp_tensor_bitdepth_minus8 must be in the range 0 to 24 (inclusive).

[0101] nnpfc_inp_order_idc indicates a method of ordering the sample array of the cropped decoded output picture as one of the input pictures of the post-processing filter.

[0102] In bitstreams conforming to this version of this document, the value of nnpfc_inp_order_idc MUST be in the range of 0 to 3, inclusive. Values ​​of nnpfc_inp_order_idc from 4 to 255, inclusive, are reserved for future use by ITU-T | ISO / IEC and MUST NOT be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document MUST ignore NNPFC SEI messages with nnpfc_inp_order_idc in the range of 4 to 255, inclusive. Values ​​of nnpfc_inp_order_idc greater than 255 MUST NOT be present in bitstreams conforming to this version of this document and are not reserved for future use.

[0103] When ChromaFormatIdc is not equal to 1, nnpfc_inp_order_idc must not be equal to 3.

[0104] Table 21 contains informative descriptions of the nnpfc_inp_order_idc values.

[0105] Table 21 - Description of nnpfc_inp_order_idc values

[0106]

[0107] Figure 1 An example of deriving a luma channel from a luma component, for example when nnpfc_inp_order_idc is equal to 3, is shown.

[0108] A tile is a rectangular array of samples of a component (eg, luma or chroma components) from a picture.

[0109] nnpfc_auxiliary_inp_idc greater than 0 indicates that auxiliary input data is present in the input tensor of the neural network post-processing filter. nnpfc_auxiliary_inp_idc equal to 0 indicates that auxiliary input data is not present in the input tensor. nnpfc_auxiliary_inp_idc equal to 1 specifies that the auxiliary input data is derived as specified in Equation 82.

[0110] In bitstreams conforming to this version of this document, the value of nnpfc_auxiliary_inp_idc MUST be in the range 0 to 1, inclusive. Values ​​of nnpfc_inp_order_idc from 2 to 255, inclusive, are reserved for future use by ITU-T | ISO / IEC and MUST NOT be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document MUST ignore NNPFC SEI messages with nnpfc_inp_order_idc in the range 2 to 255, inclusive. Values ​​of nnpfc_inp_order_idc greater than 255 MUST NOT be present in bitstreams conforming to this version of this document and are not reserved for future use.

[0111] The procedure DeriveInputTensors() for deriving an input tensor inputTensor, for a given vertical sample coordinate cTop and horizontal sample coordinate cLeft that specify the top left sample position of a patch of samples included in the input tensor, is defined as follows:

[0112]

[0113]

[0114]

[0115]

[0116] nnpfc_separate_colour_description_present_flag equal to 1 indicates that a different combination of color primaries, transfer characteristics, and matrix coefficients for the picture produced by the post-processing filters is specified in the SEI message syntax structure. nnfpc_separate_colour_description_present_flag equal to 0 indicates that the combination of color primaries, transfer characteristics, and matrix coefficients for the picture produced by the post-processing filters is the same as indicated in the VUI parameters of the CLVS.

[0117] nnpfc_colour_primaries has the same semantics as specified in subclause 7.3 for the vui_colour_primaries syntax element, except as follows:

[0118] –nnpfc_colour_primaries specifies the color primaries of the picture resulting from applying the neural network post-processing filters specified in the SEI message, instead of the color primaries used for CLVS.

[0119] – When nnpfc_colour_primaries is not present in the NNPFC SEI message, the value of nnpfc_colour_primaries is inferred to be equal to vui_colour_primaries.

[0120] nnpfc_transfer_characteristics has the same semantics as specified in subclause 7.3 for the vui_transfer_characteristics syntax element, except as follows:

[0121] –nnpfc_transfer_characteristics specifies the transfer characteristics of the picture resulting from applying the neural network post-processing filters specified in the SEI message, other than the transfer characteristics used for CLVS.

[0122] – When nnpfc_transfer_characteristics is not present in the NNPFC SEI message, the value of nnpfc_transfer_characteristics is inferred to be equal to vui_transfer_characteristics.

[0123] nnpfc_matrix_coeffs has the same semantics as specified in subclause 7.3 for the vui_matrix_coeffs syntax element, except as follows:

[0124] – The nnpfc_matrix_coeffs specifies the matrix coefficients of the picture generated by the neural network post - processing filter specified in the applied SEI message, rather than the matrix coefficients for CLVS.

[0125] – When nnpfc_matrix_coeffs is not present in the NNPFC SEI message, the value of nnpfc_matrix_coeffs is presumed to be equal to vui_matrix_coeffs.

[0126] – The allowed values of nnpfc_matrix_coeffs are not constrained by the chroma format of the decoded video picture indicated by the value of ChromaFormatIdc of the VUI parameters.

[0127] – When nnpfc_matrix_coeffs is equal to 0, nnpfc_out_order_idc must not be equal to 1 or 3.

[0128] nnpfc_out_format_idc equal to 0 indicates that the sample values output by the post - processing filter are real numbers, where the value range from 0 to 1 (including the end values) is linearly mapped to the unsigned integer value range from 0 to (1 << bitDepth) – 1 (including the end values) for any desired bit depth bitDepth for subsequent post - processing or display.

[0129] nnpfc_out_format_flag equal to 1 indicates that the sample values output by the post - processing filter are unsigned integers ranging from 0 to (1 << (nnpfc_out_tensor_bitdepth_minus8 + 8)) - 1 (including the end values).

[0130] Values of nnpfc_out_format_idc greater than 1 are reserved for future ITU - T|ISO / IEC specifications and must not be present in the bitstream conforming to this version of this document. A decoder conforming to this version of this document must ignore the NNPFC SEI message including the reserved value of nnpfc_out_format_idc.

[0131] nnpfc_out_tensor_bitdepth_minus8 plus 8 specifies the bit depth of the sample values in the output integer tensor. The value of nnpfc_out_tensor_bitdepth_minus8 must be in the range from 0 to 24 (including the end values).

[0132] nnpfc_out_order_idc indicates the output order of the samples generated by the post - processing filter.

[0133] In bitstreams conforming to this version of this document, the value of nnpfc_out_order_idc MUST be in the range of 0 to 3, inclusive. Values ​​of nnpfc_out_order_idc from 4 to 255, inclusive, are reserved for future use by ITU-T | ISO / IEC and MUST NOT be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document MUST ignore NNPFC SEI messages with nnpfc_out_order_idc in the range of 4 to 255, inclusive. Values ​​of nnpfc_out_order_idc greater than 255 MUST NOT be present in bitstreams conforming to this version of this document and are not reserved for future use.

[0134] When nnpfc_purpose is equal to 2 or 4, nnpfc_out_order_idc must not be equal to 3.

[0135] Table 22 contains informative descriptions of the nnpfc_out_order_idc values.

[0136] Table 22 - Description of nnpfc_out_order_idc values

[0137]

[0138]

[0139] The procedure StoreOutputTensors() is used to derive the sample values ​​in the filtered output sample arrays FilteredYPic, FilteredCbPic, and FilteredCrPic from the output tensor outputTensor, where the output tensor outputTensor specifies the top-left sample position of a small block of samples included in the input tensor for a given vertical sample coordinate cTop and horizontal sample coordinate cLeft. The procedure StoreOutputTensors() is specified as follows:

[0140]

[0141]

[0142]

[0143] nnpfc_constant_patch_size_flag equal to 1 indicates that the post-processing filter accepts as input the exact patch size indicated by nnpfc_patch_width_minus1 and nnpfc_patch_height_minus1. nnpfc_constant_patch_size_flag equal to 0 indicates that the post-processing filter accepts as input any patch size that is a positive integer multiple of the patch size indicated by nnpfc_patch_width_minus1 and nnpfc_patch_height_minus1.

[0144] nnpfc_patch_width_minus1+1 indicates the horizontal sample count of the patch size required for input to the post-processing filter when nnpfc_constant_patch_size_flag is equal to 1. The value of nnpfc_patch_width_minus1 must be in the range of 0 to Min(32766, CroppedWidth-1), inclusive.

[0145] nnpfc_patch_height_minus1+1 indicates the vertical sample count of the patch size required for input to the post-processing filter when nnpfc_constant_patch_size_flag is equal to 1. The value of nnpfc_patch_height_minus1 must be in the range of 0 to Min(32766, CroppedHeight-1), inclusive.

[0146] Let the variables inpPatchWidth and inpPatchHeight be the width and height of the patch size respectively.

[0147] If nnpfc_constant_patch_size_flag is equal to 0, the following applies:

[0148] – The values ​​of inpPatchWidth and inpPatchHeight are provided by external means not specified in this document or set by the post-processor itself.

[0149] –inpPatchWidth must be a positive integer multiple of nnpfc_patch_width_minus1+1 and must be less than or equal to CroppedWidth. inpPatchHeight must be a positive integer multiple of nnpfc_patch_height_minus1+1 and must be less than or equal to CroppedHeight.

[0150] Otherwise (nnpfc_constant_patch_size_flag is equal to 1), the value of inpPatchWidth is set equal to nnpfc_patch_width_minus1+1, and the value of inpPatchHeight is set equal to nnpfc_patch_height_minus1+1.

[0151] nnpfc_overlap indicates the horizontal and vertical sample counts of overlap of adjacent input tensors to the post-processing filter. The value of nnpfc_overlap must be in the range of 0 to 16383 (inclusive).

[0152] The variables outPatchWidth, outPatchHeight, horCScaling, verCScaling, outPatchCWidth, outPatchCHeight, and overlapSize are derived as follows:

[0153] outPatchWidth=(nnpfc_pic_width_in_luma_samples*inpPatchWidth) / CroppedWidth (84)

[0154] outPatchHeight=(nnpfc_pic_height_in_luma_samples*inpPatchHeight) / CroppedHeight (85)

[0155] horCScaling=SubWidthC / outSubWidthC (86)

[0156] verCScaling=SubHeightC / outSubHeightC (87)

[0157] outPatchCWidth=outPatchWidth*horCScaling (88)

[0158] outPatchCHeight=outPatchHeight*verCScaling (89)

[0159] overlapSize=nnpfc_overlap (90)

[0160] The bitstream conformance requirement is that outPatchWidth*CroppedWidth must be equal to nnpfc_pic_width_in_luma_samples*inpPatchWidth, and outPatchHeight*CroppedHeight must be equal to nnpfc_pic_height_in_luma_samples*inpPatchHeight.

[0161] nnpfc_padding_type indicates the padding process when referring to a sample position outside the boundary of the cropped decoded output picture, as described in Table 23. The value of nnpfc_padding_type must be in the range of 0 to 15 (inclusive).

[0162] Table 23 - Informative description of nnpfc_padding_type values

[0163] nnpfc_padding_type describe 0 Zero padding 1 Copy Fill 2 Reflection Fill 3 Surround Fill 4 Fixed padding 5..15 reserve

[0164] nnpfc_luma_padding_val indicates the luma value to be used for padding when nnpfc_padding_type is equal to 4.

[0165] nnpfc_cb_padding_val indicates the Cb value to be used for padding when nnpfc_padding_type is equal to 4.

[0166] nnpfc_cr_padding_val indicates the Cr value to be used for padding when nnpfc_padding_type is equal to 4.

[0167] The function InpSampleVal(y,x,picHeight,picWidth,croppedPic) takes as input the vertical sample position y, the horizontal sample position x, the picture height picHeight, the picture width picWidth, and the sample array croppedPic. The function returns the value of sampleVal derived as follows:

[0168] NOTE 6 – For the input to the function InpSampleVal(), the vertical positions are listed before the horizontal positions to be compatible with the input tensor convention of some inference engines.

[0169]

[0170]

[0171] The following example process may be used to filter the cropped decoded output picture on a tile-by-tile basis using a post-processing filter PostProcessingFilter() to generate a filtered picture comprising Y, Cb, and Cr sample arrays FilteredYPic, FilteredCbPic, and FilteredCrPic, respectively, as indicated by nnpfc_out_order_idc.

[0172]

[0173]

[0174] nnpfc_complexity_info_present_flag equal to 1 specifies that one or more syntax elements indicating the complexity of the post-processing filter associated with nnpfc_id are present. nnpfc_complexity_info_present_flag equal to 0 specifies that no syntax elements indicating the complexity of the post-processing filter associated with nnpfc_id are present.

[0175] nnpfc_parameter_type_idc equal to 0 indicates that the neural network uses only integer parameters. nnpfc_parameter_type_flag equal to 1 indicates that the neural network can use floating-point or integer parameters. nnpfc_parameter_type_idc equal to 2 indicates that the neural network uses only binary parameters. nnpfc_parameter_type_idc equal to 3 is reserved for future use by ITU-T | ISO / IEC and must not be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document must ignore NNPFCSEI messages with nnpfc_parameter_type_idc equal to 3.

[0176] nnpfc_log2_parameter_bit_length_minus3 equal to 0, 1, 2, and 3 respectively indicates that the neural network does not use parameters with bit lengths greater than 8, 16, 32, and 64. When nnpfc_parameter_type_idc is present and nnpfc_log2_parameter_bit_length_minus3 is not present, the neural network does not use parameters with bit lengths greater than 1.

[0177] nnpfc_num_parameters_idc indicates the maximum number of neural network parameters for the post-processing filter, in powers of 2048. nnpfc_num_parameters_idc equal to 0 indicates that the maximum number of neural network parameters is unknown. The value nnpfc_num_parameters_idc must be in the range of 0 to 52, inclusive. Values ​​of nnpfc_num_parameters_idc greater than 52 are reserved for future use by ITU-T | ISO / IEC and must not be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document must ignore NNPFC SEI messages with nnpfc_num_parameters_idc greater than 52.

[0178] If the value of nnpfc_num_parameters_idc is greater than 0, the variable maxNumParameters is derived as follows:

[0179] maxNumParameters=(2048< <nnpfc_num_parameters_idc)-1(93)

[0180] A bitstream conformance requirement is that the number of neural network parameters of the post-processing filters must be less than or equal to maxNumParameters.

[0181] nnpfc_num_kmac_operations_idc greater than 0 indicates that the maximum number of multiply-accumulate operations per sample of the post-processing filter is less than or equal to nnpfc_num_kmac_operations_idc * 1000. nnpfc_num_kmac_operations_idc equal to 0 indicates that the maximum number of multiply-accumulate operations of the network is unknown. The value of nnpfc_num_kmac_operations_idc must be between 0 and 2. 32 The range is -1 (including the end value).

[0182] nnpfc_total_kilobyte_size greater than 0 indicates the total size in kilobytes required to store the uncompressed parameters of the neural network. The total size in bits is a number equal to or greater than the sum of the bits used to store each parameter. nnpfc_total_kilobyte_size is the total size in bits divided by 8000, rounded up. nnpfc_total_kilobyte_size equal to 0 indicates that the total size required to store the parameters of the neural network is unknown. The value of nnpfc_total_kilobyte_size must be between 0 and 2.32 The range is -1 (including the end value).

[0183] nnpfc_reserved_zero_bit_b MUST be equal to 0 in bitstreams conforming to this version of this document. A decoder MUST ignore NNPFC SEI messages with nnpfc_reserved_zero_bit_b not equal to 0.

[0184] nnpfc_payload_byte[i] contains the i-th byte of a bitstream conforming to ISO / IEC 15938-17. For all values ​​of i present, the byte sequence nnpfc_payload_byte[i] must be a complete bitstream conforming to ISO / IEC 15938-17.

[0185] 8.29 Neural Network Post-Processing Filter Activation SEI Message

[0186] 8.29.1 Neural Network Post-Processing Filter Activation SEI Message Syntax

[0187]

[0188] 8.29.2 Neural Network Post-Processing Filter Activation SEI Message Semantics

[0189] The Neural Network Post-Processing Filter Activation (NNPFA) SEI message activates or deactivates the possible use of the target neural network post-processing filter identified by nnpfa_target_id for post-processing filtering on a set of pictures.

[0190] NOTE 1 – Multiple NNPFA SEI messages may be present for the same picture, for example when the post-processing filters are used for different purposes or filter different color components.

[0191] nnpfa_target_id indicates the target neural network post-processing filter, which is specified by one or more neural network post-processing filter characteristics SEI messages related to the current picture and with nnpfc_id equal to nnfpa_target_id.

[0192] The value of nnpfa_target_id must be between 0 and 2 32 -2 (including the end value). The value of nnpfa_target_id is from 256 to 511 (including the end value) and from 2 31 to 2 32-2 (inclusive) are reserved for future use by ITU-T|ISO / IEC. A decoder conforming to this version of this document shall encounter a nnpfa_target_id in the range 256 to 511 (inclusive) or in the range 256 to 511 (inclusive). 31 to 2 32 When an NNPFA SEI message is received in the range of -2 (inclusive), the SEI message must be ignored.

[0193] An NNPFA SEI message with a specific value of nnpfa_target_id must not be present in the current PU unless one or both of the following conditions are true:

[0194] – Within the current CLVS, an NNPFC SEI message with nnpfc_id equal to a specific value of nnpfa_target_id exists in the PU preceding the current PU in decoding order.

[0195] – There is an NNPFC SEI message with nnpfc_id equal to a specific value of nnpfa_target_id in the current PU.

[0196] When a PU includes both an NNPFC SEI message with a specific value of nnpfc_id and an NNPFA SEI message with nnpfa_target_id equal to the specific value of nnpfc_id, the NNPFC SEI message must precede the NNPFC SEI message in decoding order.

[0197] nnpfa_cancel_flag equal to 1 indicates that the persistence of the target neural network post-processing filter established by any previous NNPFA SEI message with the same nnpfa_target_id as the current SEI message is cancelled, i.e., the target neural network post-processing filter is not used again unless it is activated by another NNPFA SEI message with the same nnpfa_target_id as the current SEI message and nnpfa_cancel_flag equal to 0. nnpfa_cancel_flag equal to 0 indicates that nnpfa_persistence_flag follows.

[0198] nnpfa_persistence_flag specifies the persistence of the target neural network post-processing filters of the current layer.

[0199] nnpfa_persistence_flag equal to 0 specifies that the target neural network post-processing filter is only used for post-processing filtering of the current image.

[0200] nnpfa_persistence_flag equal to 1 specifies that the target neural network post-processing filter can be used for post-processing filtering of the current picture and all subsequent pictures of the current layer (in output order) until one or more of the following conditions are true:

[0201] – A new CLVS starts for the current layer.

[0202] – End of bitstream.

[0203] – Output the pictures in the current layer that are associated with an NNPFA SEI message that has the same nnpfa_target_id as the current SEI message and nnpfa_cancel_flag equal to 1 and that follow the current picture in output order.

[0204] NOTE 2 – The target neural network post-processing filter is not applied to this subsequent picture in the current layer that is associated with an NNPFA SEI message with the same nnpfa_target_id as the current SEI message and nnpfa_cancel_flag equal to 1.

[0205] 4. Technical Problems Solved by the Disclosed Embodiments

[0206] The example design of the Neural Network Post-Processing Filter Characteristic (NNPFC) SEI message has the following issues:

[0207] First, neural network post-processing filter (NNPF) targets are specified for chroma upsampling only, resolution upsampling only, both chroma upsampling and resolution upsampling, and picture rate upsampling only. However, combinations of picture rate upsampling with other types of upsampling can also be used in video applications. Therefore, there is a need for NNPF targets that can signal combinations of picture rate upsampling with other types of upsampling.

[0208] Second, when picture rate upsampling is used, a value is signaled to indicate the number of interpolated pictures between each pair of consecutive input pictures. However, in the most common case, the number of interpolated pictures between each pair of consecutive input pictures is the same. Therefore, it is desirable to make signaling for the common case more efficient by signaling only one value to indicate the number of interpolated pictures between each pair of consecutive input pictures.

[0209] Third, when performing multiple types of upsampling (such as chroma upsampling, resolution upsampling, and picture rate upsampling), the order may need to be explicitly specified or signaled.

[0210] Fourth, when the neural network post-processing filter (NNPF) objective is specified as visual quality improvement only, chroma upsampling only, resolution upsampling only, or chroma upsampling and resolution upsampling, only one input picture is used. However, for these objectives, it may be beneficial to input multiple pictures.

[0211] Fifth, when picture rate upsampling is performed by NNPF in combination with other types of upsampling (such as chroma upsampling and resolution upsampling) or in combination with visual quality improvement, the input picture itself is also filtered, and a filtered version of the input picture is output. For example, if the input pictures are pictures 0 and 2, and picture 1 is interpolated and output, then in the above combination mode, pictures 0 and 2 are also filtered and output. However, when NNPF with inputs of pictures 2 and 4 is applied to interpolate picture 3 in such a combination mode, picture 2 is filtered again. Therefore, there is a need for a solution for such a combination mode to enable picture rate upsampling for a video bitstream while avoiding filtering a particular input picture multiple times. When a picture is filtered multiple times, it is necessary to define / pass a signal transmission strategy to determine which filtered version will be output.

[0212] Sixth, there is a lack of mechanisms to add support for picture rate upsampling combined with visual quality improvement without adding a new NNPF object.

[0213] Seventh, when the NNPF objective is specified as visual quality improvement only, chroma upsampling only, resolution upsampling only, or chroma upsampling and resolution upsampling, even when multiple input pictures are used, only one picture is currently filtered and output. It is desirable to be able to filter and output multiple pictures in such cases.

[0214] 5. List of solutions and implementation examples

[0215] In order to solve the above problems, the following methods are disclosed. These aspects should be considered as examples to explain general concepts and should not be interpreted in a narrow sense. In addition, these examples can be applied alone or in any combination.

[0216] 1) To address issue 1, one or more of the following new objectives are defined:

[0217] a. In one example, new purposes are defined for picture rate upsampling and chroma upsampling (without resolution upsampling).

[0218] b. In one example, new purposes are defined for picture rate upsampling and resolution upsampling (without chroma upsampling).

[0219] c. In one example, new purposes are defined for picture rate upsampling, resolution upsampling, and chroma upsampling.

[0220] d. In one example, new objectives are defined for picture rate upsampling and visual quality improvement.

[0221] 2) To solve problem 2, an indication is transmitted by signaling to indicate whether the number of interpolated pictures between each pair of consecutive input pictures is the same.

[0222] a. In one example, further, when the indication of the number of interpolated pictures between each pair of consecutive input pictures is the same, an indication of the number of interpolated pictures between each pair of consecutive input pictures is signaled.

[0223] i. In one example, furthermore, the number of interpolated pictures minus one between each pair of consecutive input pictures is signaled.

[0224] 1. In one example, furthermore, the value of the quantity minus one is restricted to be in the range of 0 to N (inclusive), where N is an integer.

[0225] a. In one example, further, N is specified as 1, 3, 7, 15, 31, or 63.

[0226] 3) To solve problem 2, an indication is signaled to indicate whether the fixed output frame rate is the same, which means that the number of interpolated pictures between each pair of consecutive input pictures is the same.

[0227] a. In one example, additionally, when indicating that the number of interpolated pictures between each pair of consecutive input pictures is the same, an indication of an output frame rate or a ratio of the output frame rate to the input frame rate is further signaled.

[0228] i. In one example, furthermore, the output frame rate minus the input frame rate is signaled.

[0229] 1. Alternatively, in addition, the output frame rate minus the input frame rate minus one is transmitted via the signal.

[0230] 2. In one example, in addition, the output frame rate minus the input frame rate can be signaled by a syntax element of the ue(v) or u(N) codec.

[0231] ii. In one example, furthermore, a ratio of the output frame rate to the input frame rate is signaled.

[0232] 1. Alternatively, in addition, a ratio of the output frame rate to the input frame rate minus one is signaled.

[0233] 2. In one example, in addition, a ratio of the output frame rate to the input frame rate minus K (eg, K=0 or 1) can be signaled using multiple syntax elements.

[0234] a. Alternatively, in addition, the ratio of the output frame rate to the input frame rate can be signaled using syntax elements of the two UE(V) codecs, for example, using frr_a_minusK and frr_b_minusL, and the ratio is set equal to (frr_a_minusK+K)÷(frr_a_minusK+K-(frr_b_minusL+L)), where K and L are integer values, for example, both are 1.

[0235] 4) To solve Problem 3, when multiple types of upsampling (such as chroma upsampling, resolution upsampling, and picture rate upsampling) are performed, the order of the multiple types of upsampling may be determined, specified, or transmitted through a signal.

[0236] a. In one example, the order may be predefined or fixed.

[0237] i. In one example, it is specified that when picture rate upsampling and resolution upsampling are performed simultaneously, picture rate upsampling should be performed after / before resolution upsampling.

[0238] ii. In one example, it is specified that when chroma upsampling and resolution upsampling are performed simultaneously, chroma upsampling should be performed before / after resolution upsampling.

[0239] iii. In one example, it is specified that when chroma upsampling and picture rate upsampling are performed simultaneously, picture rate upsampling should be performed after / before chroma upsampling.

[0240] iv. In one example, the above inventions can be combined in any manner.

[0241] b. In one example, the order may be transmitted by signaling. For example, at least one syntax element may be transmitted by signaling to indicate the order of different upsampling methods.

[0242] c. In one example, the order can be adaptive.

[0243] i. In one example, the order may depend on the codec mode / statistics of the video unit (eg, prediction mode, qp, temporal layer, slice type, etc.).

[0244] d. In one example, when executing multiple types of NNPF, the order may depend on the priority of the NNPF purpose.

[0245] i. In one example, priority can be signaled.

[0246] 1. In one example, the priority can be signaled by the syntax element of the ue(v) or u(N) codec.

[0247] 2. In one example, the value of the priority is constrained to be in the range of 0 to N (inclusive), where N is an integer.

[0248] 3. In one example, a NNPF with a greater priority is executed before a NNPF with a smaller priority.

[0249] 5) To solve problem 4, the number of input images can be specified for any of the neural network post-processing filter (NNPF) objectives.

[0250] a. In one example, the number of input pictures can be specified for the purpose of visual quality improvement.

[0251] b. In one example, the number of input pictures may be specified for the purpose of chroma upsampling.

[0252] c. In one example, the number of input pictures may be specified for the purpose of resolution upsampling.

[0253] d. In one example, the number of input pictures may be specified for the purposes of chroma upsampling and resolution upsampling.

[0254] e. In one example, the number of input pictures minus one (eg, denoted as nnpfc_num_input_pics_minus1) is signaled, and the number of input pictures (eg, denoted as numInputPics) is calculated as: numInputPics=nnpfc_num_input_pics_minus1+1.

[0255] i. In one example, the constraint is that when picture rate upsampling is used, the value of nnpfc_num_input_pics_minus1 must be greater than 0.

[0256] f. In one example, the number of input pictures may be different when processing different frames. The number of input pictures may be signaled for each frame.

[0257] g. In one example, which pictures are used as input for NNPF purposes can be applied according to specific rules or adaptive rules.

[0258] i. In one example, it may depend on the codec mode / statistics of the video unit (eg, prediction mode, qp, temporal layer, slice type, etc.).

[0259] ii. In one example, it may be predefined or fixed.

[0260] 1. In one example, all reconstructed pictures in decoding order may be used as input.

[0261] 2. In one example, all reconstructed pictures in display order may be used as input.

[0262] iii. In one example, it may be transmitted via a signal.

[0263] 1. In one example, a list of indices of pictures is signaled for each frame, indicating which pictures are to be used as input.

[0264] 6) To address issues 5, 6, and 7, when multiple input pictures are used for NNPF, NNPF is allowed to generate output pictures corresponding to some input pictures but not to generate output pictures corresponding to other input pictures, and in addition, one or more of the following aspects apply:

[0265] a. In one example, when the number of input pictures is greater than 1, an indication is included in the NNPFCSEI message to indicate for which input pictures the NNPF generates corresponding output pictures, in addition to one or more pictures that may be interpolated and output by the NNPF.

[0266] b. In one example, when the purpose of the NNPF indicates that picture rate upsampling is performed by the NNPF, with or without other types of upsampling also performed by the NNPF, an indication is included in the NNPFC SEI message to indicate for which input pictures the NNPF generates corresponding output pictures, in addition to one or more pictures interpolated and output by the NNPF.

[0267] c. In one example, a specific value of the indication indicates that the NNPF does not generate a corresponding output picture for any of the input pictures. This is equivalent to picture rate upsampling without visual quality improvement for any input picture.

[0268] d. In one example, a specific value of the indication instructs NNPF to generate corresponding output pictures for all input pictures. This is equivalent to performing picture rate upsampling on all input pictures to improve visual quality.

[0269] e. In one example, a specific value of the indication instructs the NNPF to generate corresponding output pictures for all input pictures except the first input picture in the output order. This can be used to avoid filtering a specific existing picture multiple times.

[0270] f. In one example, a particular value of the indication instructs the NNPF to generate corresponding output pictures for all input pictures except the last input picture in output order.

[0271] g. In one example, whether NNPF generates a corresponding output picture for each of the input pictures is indicated separately by an indication, for example, by a flag in the indication for each of the input pictures, one value of the flag indicating that NNPF generates a corresponding output picture for the corresponding input picture, and another value of the flag indicating that NNPF does not generate a corresponding output picture for the corresponding input picture. This can be used to achieve the effects that can be achieved by items 6.c, 6.d, 6.e, and 6.f and more, for example, when NNPF only performs spatial resolution upsampling, it can obtain multiple input pictures, such as input pictures 0 to 5, and generate two output pictures, which correspond to the two input pictures in the middle of the input picture list, namely input pictures 2 and 4.

[0272] h. In one example, furthermore, when the purpose indicates that picture upsampling is not used and there are multiple input pictures, the value of the requirement indication must be such that the output picture corresponding to at least one input picture is generated by the NNPF.

[0273] i. In one example, the indication is signaled in an NNPFA SEI message.

[0274] 6. Examples

[0275] The following are some example embodiments of the aspects outlined in Section 5. Most relevant sections that have been added or modified are shown in bold font, and some of the deleted sections are shown in italic bold font. There may be some other changes that are editorial in nature and therefore not highlighted.

[0276] 6.1 Example 1

[0277] This example addresses items 1 and 2 outlined in Section 5 above, and all of their subitems.

[0278] 8.28.1 Neural Network Post-Processing Filter Characteristics SEI Message Syntax

[0279]

[0280]

[0281] 8.28.2 Neural Network Post-Processing Filter Characteristics SEI Message Semantics ...

[0283] nnpfc_purpose indicates the purpose of the post-processing filter, as specified in Table 20.

[0284] The value of nnpfc_purpose in bitstreams conforming to this version of this document must be between 0 and The value of nnpfc_purpose is from to 1023 (inclusive) are reserved for future use by ITU-T|ISO / IEC and shall not be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document shall ignore nnpfc_purpose in arrive nnpfc_purpose values ​​greater than 1023 MUST NOT be present in bitstreams conforming to this version of this document and are not reserved for future use.

[0285] Table 20 – Definition of nnpfc_purpose

[0286]

[0287] NOTE 3 – When the reserved value of nnpfc_purpose is used by ITU-T | ISO / IEC in the future, the syntax of this SEI message may be extended with the following syntax elements whose presence is conditional on nnpfc_purpose being equal to this value.

[0288] When SubWidthC is equal to 1 and SubHeightC is equal to 1, nnpfc_purpose must not be equal to 2.

[0289] nnpfc_out_sub_c_flag equal to 1 specifies that outSubWidthC is equal to 1 and outSubHeightC is equal to 1. nnpfc_out_sub_c_flag equal to 0 specifies that outSubWidthC is equal to 2 and outSubHeightC is equal to 1. When nnpfc_out_sub_c_flag is not present, outSubWidthC is inferred to be equal to SubWidthC, and outSubHeightC is inferred to be equal to SubHeightC. When ChromaFormatIdc is equal to 2 and nnpfc_out_sub_c_flag is present, the value of nnpfc_out_sub_c_flag must be equal to 1.

[0290] nnpfc_pic_width_in_luma_samples and nnpfc_pic_height_in_luma_samples specify the width and height, respectively, of the luma sample array of the picture produced by applying the post-processing filter identified by nnpfc_id to the cropped decoded output picture. When nnpfc_pic_width_in_luma_samples and nnpfc_pic_height_in_luma_samples are not present, they are inferred to be equal to CroppedWidth and CroppedHeight, respectively. The value of nnpfc_pic_width_in_luma_samples must be in the range of CroppedWidth to CroppedWidth*16-1 (inclusive). The value of nnpfc_pic_height_in_luma_samples must be in the range of CroppedHeight to CroppedHeight*16-1 (inclusive).

[0291] nnpfc_num_input_pics_minus2 plus 2 specifies the number of decoded output pictures used as input to the post-processing filter.

[0292]

[0293] nnpfc_interpolated_pics[i] specifies, The number of interpolated pictures generated by the post-processing filter between the i-th picture and the (i+1)-th picture used as input to the post-processing filter.

[0294] The variable numInputPics, which specifies the number of pictures used as input to the post-processing filter, and the variable numOutputPics, which specifies the total number of pictures produced by the post-processing filter, are derived as follows:

[0295]

[0296] nnpfc_out_order_idc indicates the output order of samples produced by the post-processing filter.

[0297] The value of nnpfc_out_order_idc MUST be in the range of 0 to 3 (inclusive) in bitstreams conforming to this version of this document. Values ​​of nnpfc_out_order_idc from 4 to 255 (inclusive) are reserved for future use by ITU-T|ISO / IEC and MUST NOT be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document MUST ignore NNPFC SEI messages with nnpfc_out_order_idc in the range of 4 to 255 (inclusive). Values ​​of nnpfc_out_order_idc greater than 255 MUST NOT be present in bitstreams conforming to this version of this document and are not reserved for future use.

[0298] When nnpfc_purpose is equal to 2, nnpfc_out_order_idc must not be equal to 3.

[0299] Table 22 contains informative descriptions of the nnpfc_out_order_idc values.

[0300] Table 22 – Description of NNPFC out-order IDC values

[0301]

[0302] The procedure StoreOutputTensors() is used to derive the sample values ​​in the filtered output sample arrays FilteredYPic, FilteredCbPic, and FilteredCrPic from the output tensor outputTensor, where the output tensor outputTensor specifies the top-left sample position of a small block of samples included in the input tensor for a given vertical sample coordinate cTop and horizontal sample coordinate cLeft. The procedure StoreOutputTensors() is specified as follows:

[0303]

[0304]

[0305]

[0306] 6.2 Example 2

[0307] This embodiment addresses items 1 and 2 outlined in Section 5 above, and all of their subitems, excluding item 1.d. 8.28.1 Neural Network Post-Processing Filter Characteristics SEI Message Syntax

[0308]

[0309]

[0310] 8.28.2 Neural Network Post-Processing Filter Characteristics SEI Message Semantics ...

[0312] nnpfc_purpose indicates the purpose of the post-processing filter, as specified in Table 20.

[0313] In bitstreams conforming to this version of this document, the value of nnpfc_purpose must be between 0 and The value of nnpfc_purpose is from to 1023 (inclusive) are reserved for future use by ITU-T|ISO / IEC and shall not be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document shall ignore nnpfc_purpose in arrive nnpfc_purpose values ​​greater than 1023 MUST NOT be present in bitstreams conforming to this version of this document and are not reserved for future use.

[0314] Table 20 – Definition of NNPF purpose

[0315]

[0316]

[0317] NOTE 3 – When the reserved value of nnpfc_purpose is used by ITU-T | ISO / IEC in the future, the syntax of this SEI message may be extended with the following syntax elements whose presence is conditional on nnpfc_purpose being equal to this value.

[0318] When SubWidthC is equal to 1 and SubHeightC is equal to 1, nnpfc_purpose must not be equal to 2.

[0319] nnpfc_out_sub_c_flag equal to 1 specifies that outSubWidthC is equal to 1 and outSubHeightC is equal to 1. nnpfc_out_sub_c_flag equal to 0 specifies that outSubWidthC is equal to 2 and outSubHeightC is equal to 1. When nnpfc_out_sub_c_flag is not present, outSubWidthC is inferred to be equal to SubWidthC, and outSubHeightC is inferred to be equal to SubHeightC. When ChromaFormatIdc is equal to 2 and nnpfc_out_sub_c_flag is present, the value of nnpfc_out_sub_c_flag must be equal to 1.

[0320] nnpfc_pic_width_in_luma_samples and nnpfc_pic_height_in_luma_samples specify the width and height, respectively, of the luma sample array of the picture produced by applying the post-processing filter identified by nnpfc_id to the cropped decoded output picture. When nnpfc_pic_width_in_luma_samples and nnpfc_pic_height_in_luma_samples are not present, they are inferred to be equal to CroppedWidth and CroppedHeight, respectively. The value of nnpfc_pic_width_in_luma_samples must be in the range of CroppedWidth to CroppedWidth*16-1 (inclusive). The value of nnpfc_pic_height_in_luma_samples must be in the range of CroppedHeight to CroppedHeight*16-1 (inclusive).

[0321] nnpfc_num_input_pics_minus2 plus 2 specifies the number of decoded output pictures used as input to the post-processing filter.

[0322] Equal to 1 indicates that the number of interpolated pictures between each pair of consecutive input pictures is the same. Equal to 0 indicates that the number of interpolated pictures between each pair of consecutive input pictures may or may not be the same. Add 1 when When equal to 1, the number of interpolated pictures between each pair of consecutive input pictures. The value must be in the range 0 to 31 (inclusive).

[0323] nnpfc_interpolated_pics[i] specifies, The number of interpolated pictures generated by the post-processing filter between the i-th picture and the (i+1)-th picture used as input to the post-processing filter.

[0324] The variable numInputPics, which specifies the number of pictures used as input to the post-processing filter, and the variable numOutputPics, which specifies the total number of pictures produced by the post-processing filter, are derived as follows:

[0325]

[0326] nnpfc_out_order_idc indicates the output order of samples produced by the post-processing filter.

[0327] The value of nnpfc_out_order_idc MUST be in the range of 0 to 3 (inclusive) in bitstreams conforming to this version of this document. Values ​​of nnpfc_out_order_idc from 4 to 255 (inclusive) are reserved for future use by ITU-T|ISO / IEC and MUST NOT be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document MUST ignore NNPFC SEI messages with nnpfc_out_order_idc in the range of 4 to 255 (inclusive). Values ​​of nnpfc_out_order_idc greater than 255 MUST NOT be present in bitstreams conforming to this version of this document and are not reserved for future use.

[0328] When nnpfc_purpose is equal to 2, nnpfc_out_order_idc must not be equal to 3.

[0329] Table 22 contains informative descriptions of the nnpfc_out_order_idc values.

[0330] Table 22 – Description of nnpfc_out_order_idc values

[0331]

[0332]

[0333] The procedure StoreOutputTensors() is used to derive the sample values ​​in the filtered output sample arrays FilteredYPic, FilteredCbPic, and FilteredCrPic from the output tensor outputTensor, where the output tensor outputTensor specifies the top-left sample position of a small block of samples included in the input tensor for a given vertical sample coordinate cTop and horizontal sample coordinate cLeft. The procedure StoreOutputTensors() is specified as follows:

[0334]

[0335]

[0336]

[0337] 6.3 Example 3

[0338] This embodiment addresses items 1, 2, and 5 outlined in Section 5 above, and all of their subitems. 8.28.1 Neural Network Post-Processing Filter Characteristics SEI Message Syntax

[0339]

[0340]

[0341] 8.28.2 Neural Network Post-Processing Filter Characteristics SEI Message Semantics ...

[0343] nnpfc_purpose indicates the purpose of the post-processing filter, as specified in Table 20.

[0344] In bitstreams conforming to this version of this document, the value of nnpfc_purpose must be between 0 and The value of nnpfc_purpose is from to 1023 (inclusive) are reserved for future use by ITU-T|ISO / IEC and shall not be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document shall ignore nnpfc_purpose in arrive nnpfc_purpose values ​​greater than 1023 MUST NOT be present in bitstreams conforming to this version of this document and are not reserved for future use.

[0345] Table 20 – Definition of nnpfc_purpose

[0346]

[0347]

[0348] NOTE 3 – When the reserved value of nnpfc_purpose is used by ITU-T | ISO / IEC in the future, the syntax of this SEI message may be extended with the following syntax elements whose presence is conditional on nnpfc_purpose being equal to this value.

[0349] When SubWidthC is equal to 1 and SubHeightC is equal to 1, nnpfc_purpose must not be equal to 2.

[0350] nnpfc_out_sub_c_flag equal to 1 specifies that outSubWidthC is equal to 1 and outSubHeightC is equal to 1. nnpfc_out_sub_c_flag equal to 0 specifies that outSubWidthC is equal to 2 and outSubHeightC is equal to 1. When nnpfc_out_sub_c_flag is not present, outSubWidthC is inferred to be equal to SubWidthC, and outSubHeightC is inferred to be equal to SubHeightC. When ChromaFormatIdc is equal to 2 and nnpfc_out_sub_c_flag is present, the value of nnpfc_out_sub_c_flag must be equal to 1.

[0351] nnpfc_pic_width_in_luma_samples and nnpfc_pic_height_in_luma_samples specify the width and height, respectively, of the luma sample array of the picture produced by applying the post-processing filter identified by nnpfc_id to the cropped decoded output picture. When nnpfc_pic_width_in_luma_samples and nnpfc_pic_height_in_luma_samples are not present, they are inferred to be equal to CroppedWidth and CroppedHeight, respectively. The value of nnpfc_pic_width_in_luma_samples must be in the range of CroppedWidth to CroppedWidth*16-1 (inclusive). The value of nnpfc_pic_height_in_luma_samples must be in the range of CroppedHeight to CroppedHeight*16-1 (inclusive).

[0352] add Specifies the number of decoded output pictures used as input to the post-processing filters.

[0353] Equal to 1 indicates that the number of interpolated pictures between each pair of consecutive input pictures is the same. Equal to 0 indicates that the number of interpolated pictures between each pair of consecutive input pictures may or may not be the same. Add 1 when When equal to 1, the number of interpolated pictures between each pair of consecutive input pictures. The value must be in the range 0 to 31 (inclusive).

[0354] nnpfc_interpolated_pics[i] specifies, The number of interpolated pictures generated by the post-processing filter between the i-th picture and the (i+1)-th picture used as input to the post-processing filter.

[0355] The variable numInputPics, which specifies the number of pictures used as input to the post-processing filter, and the variable numOutputPics, which specifies the total number of pictures produced by the post-processing filter, are derived as follows:

[0356]

[0357] nnpfc_out_order_idc indicates the output order of samples produced by the post-processing filter.

[0358] The value of nnpfc_out_order_idc MUST be in the range of 0 to 3 (inclusive) in bitstreams conforming to this version of this document. Values ​​of nnpfc_out_order_idc from 4 to 255 (inclusive) are reserved for future use by ITU-T|ISO / IEC and MUST NOT be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document MUST ignore NNPFC SEI messages with nnpfc_out_order_idc in the range of 4 to 255 (inclusive). Values ​​of nnpfc_out_order_idc greater than 255 MUST NOT be present in bitstreams conforming to this version of this document and are not reserved for future use.

[0359] When nnpfc_purpose is equal to 2, nnpfc_out_order_idc must not be equal to 3.

[0360] Table 22 contains informative descriptions of the nnpfc_out_order_idc values.

[0361] Table 22 – Description of nnpfc_out_order_idc values

[0362]

[0363]

[0364] The procedure StoreOutputTensors() is used to derive the sample values ​​in the filtered output sample arrays FilteredYPic, FilteredCbPic, and FilteredCrPic from the output tensor outputTensor, where the output tensor outputTensor specifies the top-left sample position of a small block of samples included in the input tensor for a given vertical sample coordinate cTop and horizontal sample coordinate cLeft. The procedure StoreOutputTensors() is specified as follows:

[0365]

[0366]

[0367]

[0368] 6.4 Example 4

[0369] This embodiment addresses items 1, 5, 6, and some of their subitems outlined in Section 5 above. 8.28.1 Neural Network Post-Processing Filter Characteristics SEI Message Syntax

[0370]

[0371]

[0372] 8.28.2 Neural Network Post-Processing Filter Characteristics SEI Message Semantics ...

[0374] nnpfc_purpose indicates the purpose of the post-processing filter, as specified in Table 20.

[0375] In bitstreams conforming to this version of this document, the value of nnpfc_purpose must be between 0 and The value of nnpfc_purpose is from to 1023 (inclusive) are reserved for future use by ITU-T|ISO / IEC and shall not be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document shall ignore nnpfc_purpose in arrive nnpfc_purpose values ​​greater than 1023 MUST NOT be present in bitstreams conforming to this version of this document and are not reserved for future use.

[0376] Table 20 – Definition of nnpfc_purpose

[0377]

[0378]

[0379] NOTE 3 – When the reserved value of nnpfc_purpose is used by ITU-T | ISO / IEC in the future, the syntax of this SEI message may be extended with the following syntax elements whose presence is conditional on nnpfc_purpose being equal to this value.

[0380] When SubWidthC is equal to 1 and SubHeightC is equal to 1, nnpfc_purpose must not be equal to 2.

[0381] nnpfc_out_sub_c_flag equal to 1 specifies that outSubWidthC is equal to 1 and outSubHeightC is equal to 1. nnpfc_out_sub_c_flag equal to 0 specifies that outSubWidthC is equal to 2 and outSubHeightC is equal to 1. When nnpfc_out_sub_c_flag is not present, outSubWidthC is inferred to be equal to SubWidthC, and outSubHeightC is inferred to be equal to SubHeightC. When ChromaFormatIdc is equal to 2 and nnpfc_out_sub_c_flag is present, the value of nnpfc_out_sub_c_flag must be equal to 1.

[0382] nnpfc_pic_width_in_luma_samples and nnpfc_pic_height_in_luma_samples specify the width and height, respectively, of the luma sample array of the picture produced by applying the post-processing filter identified by nnpfc_id to the cropped decoded output picture. When nnpfc_pic_width_in_luma_samples and nnpfc_pic_height_in_luma_samples are not present, they are inferred to be equal to CroppedWidth and CroppedHeight, respectively. The value of nnpfc_pic_width_in_luma_samples must be in the range of CroppedWidth to CroppedWidth*16-1 (inclusive). The value of nnpfc_pic_height_in_luma_samples must be in the range of CroppedHeight to CroppedHeight*16-1 (inclusive).

[0383] add Specifies the number of decoded output pictures used as input to the post-processing filters.

[0384]

[0385] In one example, furthermore, when the purpose indicates that picture upsampling is not used and there are multiple input pictures, the value of the requirement indication must be such that at least one input picture is filtered and output by the NNPF.

[0386] nnpfc_interpolated_pics[i] specifies the number of interpolated pictures generated by the post-processing filter between the i-th picture and the (i+1)-th picture used as input to the post-processing filter.

[0387] The variable numInputPics, which specifies the number of pictures used as input to the post-processing filter, and the variable numOutputPics, which specifies the total number of pictures produced by the post-processing filter, are derived as follows:

[0388]

[0389] nnpfc_out_order_idc indicates the output order of samples produced by the post-processing filter.

[0390] The value of nnpfc_out_order_idc MUST be in the range of 0 to 3 (inclusive) in bitstreams conforming to this version of this document. Values ​​of nnpfc_out_order_idc from 4 to 255 (inclusive) are reserved for future use by ITU-T|ISO / IEC and MUST NOT be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document MUST ignore NNPFC SEI messages with nnpfc_out_order_idc in the range of 4 to 255 (inclusive). Values ​​of nnpfc_out_order_idc greater than 255 MUST NOT be present in bitstreams conforming to this version of this document and are not reserved for future use.

[0391] When nnpfc_purpose is equal to 2, nnpfc_out_order_idc must not be equal to 3.

[0392] Table 22 contains informative descriptions of the nnpfc_out_order_idc values.

[0393] Table 22 – Description of nnpfc_out_order_idc values

[0394]

[0395] The procedure StoreOutputTensors() is used to derive the sample values ​​in the filtered output sample arrays FilteredYPic, FilteredCbPic, and FilteredCrPic from the output tensor outputTensor, where the output tensor outputTensor specifies the top-left sample position of a small block of samples included in the input tensor for a given vertical sample coordinate cTop and horizontal sample coordinate cLeft. The procedure StoreOutputTensors() is specified as follows:

[0396]

[0397]

[0398]

[0399] The following example procedure can be used to Using the post-processing filter PostProcessingFilter() Generate filtered The picture(s) respectively include a Y sample array FilteredYPic, a Cb sample array FilteredCbPic, and a Cr sample array FilteredCrPic, as indicated by nnpfc_out_order_idc.

[0400]

[0401]

[0402] 6.5 Example 5

[0403] This embodiment addresses invention items 1, 5, and 6, as outlined in Section 5 above, and some of their subitems. 8.28.1 Neural Network Post-Processing Filter Characteristics SEI Message Syntax

[0404]

[0405]

[0406] 8.28.2 Neural Network Post-Processing Filter Characteristics SEI Message Semantics ...

[0408] nnpfc_purpose indicates the purpose of the post-processing filter, as specified in Table 20.

[0409] In bitstreams conforming to this version of this document, the value of nnpfc_purpose must be between 0 and The value of nnpfc_purpose is from to 1023 (inclusive) are reserved for future use by ITU-T|ISO / IEC and shall not be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document shall ignore nnpfc_purpose in arrive nnpfc_purpose values ​​greater than 1023 MUST NOT be present in bitstreams conforming to this version of this document and are not reserved for future use.

[0410] Table 20 – Definition of nnpfc_purpose

[0411]

[0412] NOTE 3 – When the reserved value of nnpfc_purpose is used by ITU-T | ISO / IEC in the future, the syntax of this SEI message may be extended with the following syntax elements whose presence is conditional on nnpfc_purpose being equal to this value.

[0413] When SubWidthC is equal to 1 and SubHeightC is equal to 1, nnpfc_purpose must not be equal to 2.

[0414] nnpfc_out_sub_c_flag equal to 1 specifies that outSubWidthC is equal to 1 and outSubHeightC is equal to 1. nnpfc_out_sub_c_flag equal to 0 specifies that outSubWidthC is equal to 2 and outSubHeightC is equal to 1. When nnpfc_out_sub_c_flag is not present, outSubWidthC is inferred to be equal to SubWidthC, and outSubHeightC is inferred to be equal to SubHeightC. When ChromaFormatIdc is equal to 2 and nnpfc_out_sub_c_flag is present, the value of nnpfc_out_sub_c_flag must be equal to 1.

[0415] nnpfc_pic_width_in_luma_samples and nnpfc_pic_height_in_luma_samples specify the width and height, respectively, of the luma sample array of the picture produced by applying the post-processing filter identified by nnpfc_id to the cropped decoded output picture. When nnpfc_pic_width_in_luma_samples and nnpfc_pic_height_in_luma_samples are not present, they are inferred to be equal to CroppedWidth and CroppedHeight, respectively. The value of nnpfc_pic_width_in_luma_samples must be in the range of CroppedWidth to CroppedWidth*16-1 (inclusive). The value of nnpfc_pic_height_in_luma_samples must be in the range of CroppedHeight to CroppedHeight*16-1 (inclusive).

[0416] add Specifies the number of decoded output pictures used as input to the post-processing filters.

[0417]

[0418] nnpfc_interpolated_pics[i] specifies the number of interpolated pictures generated by the post-processing filter between the i-th picture and the (i+1)-th picture used as input to the post-processing filter.

[0419] The variable numInputPics, which specifies the number of pictures used as input to the post-processing filter, and the variable numOutputPics, which specifies the total number of pictures produced by the post-processing filter, are derived as follows:

[0420]

[0421] nnpfc_out_order_idc indicates the output order of samples produced by the post-processing filter.

[0422] The value of nnpfc_out_order_idc MUST be in the range of 0 to 3 (inclusive) in bitstreams conforming to this version of this document. Values ​​of nnpfc_out_order_idc from 4 to 255 (inclusive) are reserved for future use by ITU-T|ISO / IEC and MUST NOT be present in bitstreams conforming to this version of this document. Decoders conforming to this version of this document MUST ignore NNPFC SEI messages with nnpfc_out_order_idc in the range of 4 to 255 (inclusive). Values ​​of nnpfc_out_order_idc greater than 255 MUST NOT be present in bitstreams conforming to this version of this document and are not reserved for future use.

[0423] When nnpfc_purpose is equal to 2, nnpfc_out_order_idc must not be equal to 3.

[0424] Table 22 contains informative descriptions of the nnpfc_out_order_idc values.

[0425] Table 22 – Description of nnpfc_out_order_idc values

[0426]

[0427] The procedure StoreOutputTensors() is used to derive the sample values ​​in the filtered output sample arrays FilteredYPic, FilteredCbPic, and FilteredCrPic from the output tensor outputTensor, where the output tensor outputTensor specifies the top-left sample position of a small block of samples included in the input tensor for a given vertical sample coordinate cTop and horizontal sample coordinate cLeft. The procedure StoreOutputTensors() is specified as follows:

[0428]

[0429]

[0430]

[0431] The following example procedure can be used to Using the post-processing filter PostProcessingFilter() Generate filtered The picture(s) respectively include a Y sample array FilteredYPic, a Cb sample array FilteredCbPic, and a Cr sample array FilteredCrPic, as indicated by nnpfc_out_order_idc.

[0432]

[0433]

[0434] 7. References

[0435] [1]ITU-T and ISO / IEC, "High efficiency video coding", Rec.ITU-T H.265|ISO / IEC 23008-2 (in force edition).

[0436] [2] J.Chen, E.Alshina, GJSullivan, J.-R.Ohm, J.Boyce, "Algorithmdescription of Joint Exploration Test Model 7(JEM7)," JVET-G1001, Aug.2017.

[0437] [3]Rec.ITU-T H.266|ISO / IEC 23090-3, "Versatile Video Coding", 2022.

[0438] [4]Rec.ITU-T Rec.H.274|ISO / IEC 23002-7, "Versatile SupplementalEnhancement Information Messages for Coded Video Bitstreams", 2022.

[0439] [5]ISO / IEC JTC 1 / SC 29 / WG 05output document N0158, "Text of ISO / IEC23002-7:202x(2nd Ed.)DAM 1Information technology—MPEG video technologies—Part 7:Versatile supplemental enhancement information messages for codedvideo bitstreams,AMENDMENT1:Additional SEI messages",Oct.2022.

[0440] [6]S.McCarthy,T.Chujoh,M.Hannuksela,G.Sullivan,and Y.-K.Wang(editors),"Additional SEI messages for VSEI(Draft 3),"JVET output documentJVET-AB2006,publicly available online herein:https: / / www.jvet-experts.org / doc_end_user / current_document.php? id=12215.

[0441] Figure 2 is a block diagram illustrating an example video processing system 4000 in which various embodiments disclosed herein may be implemented. Various implementations may include some or all of the components of system 4000. System 4000 may include an input 4002 for receiving video content. The video content may be received in a raw or uncompressed format, such as 8 or 10-bit multi-component pixel values, or may be in a compressed or encoded format. Input 4002 may represent a network interface, a peripheral bus interface, or a storage interface. Examples of network interfaces include wired interfaces such as Ethernet, a passive optical network (PON), and wireless interfaces such as Wi-Fi or a cellular interface.

[0442] System 4000 may include a codec component 4004 that can implement the various codecs or encoding methods described in this disclosure. Codec component 4004 can reduce the average bit rate of the video from input 4002 to the output of codec component 4004 to generate a codec representation of the video. Codec technology is therefore sometimes referred to as video compression or video transcoding technology. The output of codec component 4004 can be stored or transmitted via a communication connection such as represented by component 4006. The bitstream (or codec) representation of the video stored or communicated at input 4002 can be used by component 4008 to generate pixel values ​​or displayable video that is sent to display interface 4010. The process of generating user-visible video from the bitstream representation is sometimes referred to as video decompression. In addition, although some video processing operations are referred to as "codec" operations or tools, it should be understood that the codec tools or operations are used at the encoder, and the corresponding decoding tools or operations that reverse the codec results will be performed by the decoder.

[0443] Examples of peripheral bus interfaces or display interfaces may include a universal serial bus (USB) or a high-definition multimedia interface (HDMI) or a display interface, etc. Examples of storage interfaces include a serial advanced technology attachment (SATA), a peripheral component interconnect (PCI), an integrated drive electronics (IDE) interface, etc. The embodiments described in the present disclosure may be embodied in various electronic devices, such as mobile phones, laptop computers, smart phones, or other devices capable of performing digital data processing and / or video display.

[0444] Figure 3 is a block diagram of an example video processing device 4100. Device 4100 can be used to implement one or more methods described herein. Device 4100 can be embodied in a smartphone, a tablet computer, a computer, an Internet of Things (IoT) receiver, etc. Device 4100 may include one or more processors 4102, one or more memories 4104, and video processing circuitry 4106. Processor(s) 4102 can be configured to implement one or more methods described in the present disclosure. Memory(s) 4104 can be used to store data and code for implementing the methods and embodiments described herein. Video processing circuitry 4106 can be used to implement some embodiments described in the present disclosure in hardware circuitry. In some embodiments, video processing circuitry 4106 can be at least partially included in processor 4102, such as a graphics coprocessor.

[0445] Figure 44 is a flow chart of an example method 4200 for video processing. At step 4202, method 4200 determines a neural network post-processing filter (NNPF) objective based on a neural network post-processing filter characteristic (NNPFC) supplemental enhancement information (SEI) message. At step 4204, conversion between visual media data and a bitstream is performed based on the NNPF objective.

[0446] It should be noted that method 4200 can be implemented in an apparatus for processing video data that includes a processor and a non-transitory memory having instructions thereon, such as video encoder 4400, video decoder 4500, and / or encoder 4600. In this case, the instructions, when executed by the processor, cause the processor to perform method 4200. Furthermore, method 4200 can be performed by a non-transitory computer-readable medium including a computer program product for use by a video codec device. The computer program product includes computer-executable instructions stored on a non-transitory computer-readable medium, such that when executed by the processor, the video codec device performs method 4200.

[0447] Figure 5 is a block diagram illustrating an example video codec system 4300 in which embodiments of the present disclosure may be utilized. Video codec system 4300 may include a source device 4310 and a destination device 4320. Source device 4310 generates encoded video data, where source device 4310 may be referred to as a video encoding device. Destination device 4320 may decode the encoded video data generated by source device 4310, where destination device 4320 may be referred to as a video decoding device.

[0448] 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 for receiving video data from a video content provider, and / or a computer graphics system for generating video data, or a combination of these sources. The video data may include one or more pictures. 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 codec representation of the video data. The bitstream may include a coded picture and associated data. A coded picture is a coded representation of the picture. Associated data may include sequence parameter sets, picture parameter sets, and other syntax structures. I / O interface 4316 may include a modulator / demodulator (modem) and / or a transmitter. The coded video data may be transmitted directly to destination device 4320 via network 4330 via I / O interface 4316. The coded video data may also be stored on storage medium / server 4340 for access by destination device 4320.

[0449] Destination device 4320 may include an I / O interface 4326, a video decoder 4324, and a display device 4322. The I / O interface 4326 may include a receiver and / or a modem. The I / O interface 4326 may obtain encoded video data from source device 4310 or storage medium / server 4340. The video decoder 4324 may decode the encoded video data. The display device 4322 may display the decoded video data to a user. The display device 4322 may be integrated with the destination device 4320, or may be external to the destination device 4320, wherein the destination device 4320 may be configured to be connected to an external display device interface.

[0450] The video encoder 4314 and the video decoder 4324 may operate according to a video compression standard, such as the HEVC standard, the VVC standard, and other existing and / or further standards.

[0451] Figure 6 is a block diagram illustrating an example of a video encoder 4400, wherein the video encoder 4400 may be Figure 5 Video encoder 4314 in system 4300 is shown. Video encoder 4400 can be configured to perform any or all embodiments of the present disclosure. Video encoder 4400 includes multiple functional components. The embodiments described in this disclosure can be shared between the various components of video encoder 4400. In some examples, a processor can be configured to perform any or all embodiments described in this disclosure.

[0452] The functional components of the video encoder 4400 may include a segmentation unit 4401; a prediction unit 4402, which may include a mode selection unit 4403, a motion estimation unit 4404, a motion compensation unit 4405 and an intra-frame 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 cache 4413; and an entropy coding unit 4414.

[0453] In other examples, the video encoder 4400 may include more, fewer, or different functional components. In one example, the prediction unit 4402 may include an intra block copy (IBC) unit. The IBC unit may perform prediction in accordance with an IBC mode, where at least one reference picture is a picture in which the current video block is located.

[0454] Furthermore, some components, such as the motion estimation unit 4404 and the motion compensation unit 4405 , may be highly integrated, but are represented separately in the example of the video encoder 4400 for purposes of explanation.

[0455] The segmentation unit 4401 may segment a picture into one or more video blocks. The video encoder 4400 and the video decoder 4500 may support various video block sizes.

[0456] The mode selection unit 4403 can, for example, select one of a plurality of codec modes (intra-frame codec or inter-frame codec) based on the error result, and provide the generated intra-frame codec block or inter-frame codec block to the residual generation unit 4407 to generate residual block data, and to the reconstruction unit 4412 to reconstruct the coded block for use as a reference picture. In some examples, the mode selection unit 4403 can select a joint intra-frame and inter-frame prediction (CIIP) mode, in which prediction is based on an inter-frame prediction signal and an intra-frame prediction signal. In the case of inter-frame prediction, the mode selection unit 4403 can also select a resolution for the motion vector for the block (e.g., sub-pixel precision or integer pixel precision).

[0457] To perform inter-frame prediction on the current video block, the motion estimation unit 4404 may generate motion information for the current video block by comparing the current video block with one or more reference frames from the buffer 4413. The 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 the buffer 4413 other than the picture associated with the current video block.

[0458] The motion estimation unit 4404 and the motion compensation unit 4405 may perform different operations on the current video block, eg, depending on whether the current video block is in an I slice, a P slice, or a B slice.

[0459] In some examples, motion estimation unit 4404 may perform unidirectional prediction on the current video block, and motion estimation unit 4404 may search the reference pictures of list 0 or list 1 to find a reference video block for the current video block. Motion estimation unit 4404 may then generate a reference index indicating a reference picture in list 0 or list 1, the reference picture including the reference video block and a motion vector indicating a spatial displacement between the current video block and the reference video block. Motion estimation unit 4404 may output the reference index, the prediction direction indicator, and the motion vector as motion information for the current video block. Motion compensation unit 4405 may generate a predicted video block for the current block based on the reference video block indicated by the motion information for the current video block.

[0460] In other examples, motion estimation unit 4404 may perform bidirectional prediction on 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 indicating the reference pictures in list 0 and list 1 that include the reference video blocks, and a motion vector indicating the spatial displacement between the reference video blocks and the current video block. Motion estimation unit 4404 may output the reference index and motion vector of the current video block as motion information for the current video block. Motion compensation unit 4405 may generate a predicted video block for the current video block based on the reference video block indicated by the motion information of the current video block.

[0461] In some examples, motion estimation unit 4404 can output a complete set of motion information for use in the decoding process of a decoder. In some examples, motion estimation unit 4404 may not output a complete set of motion information for the current video. Instead, motion estimation unit 4404 can reference motion information of another video block to signal the motion information of the current video block. For example, motion estimation unit 4404 can determine that the motion information of the current video block is sufficiently similar to the motion information of a neighboring video block.

[0462] In one example, the motion estimation unit 4404 may indicate to the video decoder 4500 a value in a syntax structure associated with the current video block that indicates that the current video block has the same motion information as another video block.

[0463] In another example, the motion estimation unit 4404 may identify another video block and a motion vector difference (MVD) in a syntax structure associated with the current video block. The motion vector difference indicates the 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.

[0464] As discussed above, the video encoder 4400 can signal motion vectors in a predictive manner.Two examples of prediction signaling techniques that can be implemented by the video encoder 4400 include Advanced Motion Vector Prediction (AMVP) and Merge mode signaling.

[0465] Intra-frame prediction unit 4406 can perform intra-frame prediction on the current video block. When intra-frame prediction unit 4406 performs intra-frame prediction on the current video block, intra-frame prediction unit 4406 can generate prediction data for the current video block based on decoded samples of other video blocks in the same picture. The prediction data for the current video block can include a predicted video block and various syntax elements.

[0466] The residual generation unit 4407 can generate residual data for the current video block by subtracting the predicted video blocks of the current video block from the current video block. The residual data of the current video block may include residual video blocks corresponding to different sample components of the samples in the current video block.

[0467] In other examples, such as in skip mode, there may be no residual data for the current video block and the residual generation unit 4407 may not perform a subtraction operation.

[0468] Transform processing unit 4408 may generate one or more transform coefficient video blocks for a current video block by applying one or more transforms to a residual video block associated with the current video block.

[0469] After the transform processing unit 4408 generates a transform coefficient video block associated with the current video block, the 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.

[0470] The inverse quantization unit 4410 and the inverse transform unit 4411 may apply inverse quantization and inverse transform, respectively, to the transform coefficient video block to reconstruct a residual video block from the transform coefficient video block. The reconstruction unit 4412 may add the reconstructed residual video block to corresponding samples from one or more prediction video blocks generated by the prediction unit 4402 to generate a reconstructed video block associated with the current block for storage in the buffer 4413.

[0471] After the reconstruction unit 4412 reconstructs the video block, a loop filtering operation may be performed to reduce video block artifacts in the video block.

[0472] The entropy coding unit 4414 may receive data from other functional components of the video encoder 4400. When the entropy coding unit 4414 receives data, the entropy coding unit 4414 may perform one or more entropy coding operations to generate entropy-coded data and output a bitstream including the entropy-coded data.

[0473] Figure 7 is a block diagram illustrating an example of a video decoder 4500, wherein the video decoder 4500 may be Figure 5 Video decoder 4324 in system 4300 is shown. Video decoder 4500 can be configured to perform any or all embodiments of the present disclosure. In the example shown, video decoder 4500 includes multiple functional components. The embodiments described in this disclosure can be shared between the various components of video decoder 4500. In some examples, a processor can be configured to perform any or all embodiments described in this disclosure.

[0474] 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 transform unit 4505, a reconstruction unit 4506, and a buffer 4507. In some examples, video decoder 4500 may perform a decoding process that is generally opposite to the encoding process described with respect to video encoder 4400.

[0475] The entropy decoding unit 4501 can retrieve the encoded bitstream. The encoded bitstream may include entropy-encoded video data (e.g., coded blocks of video data). The entropy decoding unit 4501 can decode the entropy-encoded video data, and based on the entropy-encoded video data, the motion compensation unit 4502 can determine motion information including motion vectors, motion vector precision, reference picture list index, and other motion information. The motion compensation unit 4502 can determine this information, for example, by performing AMVP and Merge modes.

[0476] The motion compensation unit 4502 may generate a motion compensated block, possibly performing interpolation based on an interpolation filter. An identifier of the interpolation filter to be used with sub-pixel precision may be included in the syntax element.

[0477] The motion compensation unit 4502 may calculate interpolated values ​​for sub-integer pixels of a reference block using interpolation filters used by the video encoder 4400 during encoding of the video block. The motion compensation unit 4502 may determine the interpolation filters used by the video encoder 4400 based on received syntax information, and the motion compensation unit 4502 may use the interpolation filters to generate a prediction block.

[0478] The motion compensation unit 4502 can use some syntax information to determine the size of the blocks used to encode (multiple) frames and / or (multiple) slices of the encoded video sequence, partitioning information describing how each macroblock of the pictures of the encoded video sequence is partitioned, a mode indicating how each partition is encoded, one or more reference frames (and reference frame lists) for each inter-frame codec block, and other information used to decode the encoded video sequence.

[0479] The intra prediction unit 4503 can form a prediction block from spatially neighboring blocks using, for example, an intra prediction mode received in the bitstream. The inverse quantization unit 4504 inversely quantizes (i.e., dequantizes) the quantized video block coefficients provided in the bitstream and decoded by the entropy decoding unit 4501. The inverse transform unit 4505 applies an inverse transform.

[0480] The reconstruction unit 4506 can sum the residual block with the corresponding prediction block generated by the motion compensation unit 4502 or the intra-frame prediction unit 4503 to form a decoded block. If necessary, a deblocking filter can also be used to filter the decoded block to remove blocking artifacts. The decoded video block is then stored in a buffer 4507, which provides reference blocks for subsequent motion compensation / intra-frame prediction and also produces decoded video for presentation on a display device.

[0481] Figure 8 is a schematic diagram of an example encoder 4600. The encoder 4600 is suitable for implementing techniques for VVC. The encoder 4600 includes three 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 a predefined filter, the SAO 4604 and the ALF 4606 use the original samples of the current picture to reduce the mean square error between the original samples and the reconstructed samples by adding an offset and applying a finite impulse response (FIR) filter, respectively, and using the encoded side information to signal the offset and filter coefficients. The ALF 4606 is located at the last processing stage for each picture and can be seen as a tool that attempts to capture and repair artifacts caused by previous stages.

[0482] The encoder 4600 also includes an intra-frame prediction component 4608 and a motion estimation / compensation (ME / MC) component 4610 configured to receive input video. The intra-frame prediction component 4608 is configured to perform intra-frame prediction, while the ME / MC component 4610 is configured to perform inter-frame prediction using reference pictures obtained from a reference picture cache 4612. The residual block from the inter-frame prediction or intra-frame prediction is 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 codec component 4618. The entropy codec component 4618 performs entropy coding and decoding on the prediction results and quantized transform coefficients and sends them to a video decoder (not shown). The quantization component output from the quantization component 4616 can be fed into an inverse quantization (IQ) component 4620, an inverse transform component 4622, and a reconstruction (REC) component 4624. The REC component 4624 can output images to the DF 4602 , SAO 4604 , and ALF 4606 for filtering before these images are stored in the reference picture cache 4612 .

[0483] A list of some example preferred solutions is provided below.

[0484] The following solutions illustrate examples of the embodiments discussed herein.

[0485] 1. A method for processing media data, comprising: determining a neural network post-processing filter (NNPF) purpose based on a neural network post-processing filter characteristic (NNPFC) supplemental enhancement information (SEI) message; and performing conversion between visual media data and a bitstream based on the NNPF purpose.

[0486] 2. The method according to solution 1, wherein the NNPF purpose is picture rate upsampling and chroma upsampling, without resolution upsampling.

[0487] 3. A method according to any one of solutions 1-2, wherein the NNPF purpose is picture rate upsampling and resolution upsampling, without chroma upsampling.

[0488] 4. A method according to any one of solutions 1-3, wherein the NNPF purpose is picture rate upsampling, resolution upsampling and chroma upsampling.

[0489] 5. The method according to any of solutions 1-4, wherein the bitstream includes an indication to indicate whether the number of interpolated pictures between each pair of consecutive input pictures is the same.

[0490] 6. A method according to any one of solutions 1-5, wherein, when the indication indicates that the number of interpolated pictures between each pair of consecutive input pictures is the same, the bitstream also includes an indication of the number of interpolated pictures between each pair of consecutive input pictures.

[0491] 7. A method according to any of solutions 1-6, wherein the number of interpolated pictures minus one between each pair of consecutive input pictures is included in the bitstream.

[0492] 8. The method according to any of solutions 1-7, wherein the number of interpolated pictures minus one between each pair of consecutive input pictures is limited to the range of 0 to N, where N is an integer.

[0493] 9. A method according to any one of solutions 1-8, wherein N is specified as 1, 3, 7, 15, 31 or 63.

[0494] 10. The method of any one of solutions 1-9, wherein the bitstream includes an indication to indicate whether the fixed output frame rate is constant.

[0495] 11. A method according to any of solutions 1-10, wherein an indication of the output frame rate is included in the bitstream when the number of interpolated pictures between each pair of consecutive input pictures is the same.

[0496] 12. The method of any one of solutions 1-11, wherein the output frame rate is transmitted via a signal as the output frame rate minus the input frame rate.

[0497] 13. The method of any one of solutions 1-12, wherein the output frame rate is transmitted via a signal as a ratio of the output frame rate to the input frame rate.

[0498] 14. The method according to any of the solutions 1-13, wherein the conversion comprises multiple types of upsampling, and wherein an order of the types of upsampling is determined.

[0499] 15. The method according to any of solutions 1-14, wherein the order of upsampling of the types is indicated in the bitstream.

[0500] 16. The method according to any one of solutions 1-15, wherein when picture rate upsampling and resolution upsampling are performed simultaneously, picture rate upsampling is performed before resolution upsampling.

[0501] 17. The method according to any one of solutions 1-16, wherein, when chroma upsampling and resolution upsampling are performed simultaneously, chroma upsampling is performed before resolution upsampling.

[0502] 18. The method according to any one of solutions 1-17, wherein when chroma upsampling and picture rate upsampling are performed simultaneously, picture rate upsampling is performed after chroma upsampling.

[0503] 19. The method according to any of solutions 1-18, wherein the order of upsampling of the types is an adaptive order based on the codec mode or statistics of the corresponding video unit.

[0504] 20. A method according to any one of solutions 1-19, wherein, when performing multiple types of NNPF, the order of upsampling of the types depends on the priority of the NNPF purpose.

[0505] 21. The method according to any of the solutions 1-20, wherein the number of input pictures is specified for the purpose of visual quality improvement.

[0506] 22. The method according to any of the solutions 1-21, wherein the number of input pictures is specified for the purpose of chroma upsampling.

[0507] 23. The method according to any of the solutions 1-22, wherein the number of input pictures is specified for the purpose of resolution upsampling.

[0508] 24. The method according to any of the solutions 1-23, wherein the number of input pictures is specified for the purpose of chroma upsampling and resolution upsampling.

[0509] 25. The method according to any of the solutions 1-24, wherein the number of input pictures minus 1 (nnpfc_num_input_pics_minus1) is transmitted by signal, and wherein the number of input pictures (numInputPics) is calculated as: numInputPics=nnpfc_num_input_pics_minus1+1.

[0510] 26. The method according to any of the solutions 1-25, wherein the number of input pictures is signaled for each frame.

[0511] 27. A method according to any one of solutions 1-26, wherein the pictures used as input for NNPF purposes are applied according to rules, and wherein the rules indicate that the pictures used as input for NNPF purposes depend on the codec mode of the video unit, are predefined or are transmitted via a signal.

[0512] 28. A device for processing video data, comprising: a processor; and a non-transitory memory having instructions thereon, wherein the instructions, when executed by the processor, cause the processor to perform the method according to any one of Solutions 1-27.

[0513] 29. A non-transitory computer-readable medium comprising a computer program product for use with a video codec device, the computer program product comprising computer-executable instructions stored on the non-transitory computer-readable medium, such that when executed by a processor, the video codec device performs a method according to any one of Solutions 1-27.

[0514] 30. A non-transitory computer-readable recording medium storing a bitstream of a video generated by a method performed by a video processing device, wherein the method includes: determining a neural network post-processing filter (NNPF) purpose based on a neural network post-processing filter characteristic (NNPFC) supplemental enhancement information (SEI) message; and generating a bitstream based on the determination.

[0515] 31. A method for storing a bitstream of a video, comprising: determining a neural network post-processing filter (NNPF) purpose based on a neural network post-processing filter characteristic (NNPFC) supplemental enhancement information (SEI) message; generating a bitstream based on the determination; and storing the bitstream in a non-temporary computer-readable recording medium.

[0516] 32. A method, apparatus or system as described in the present disclosure.

[0517] In the described solution, an encoder can conform to the format rules by generating a codec representation according to the format rules. In the described solution, a decoder can parse syntax elements in the codec representation according to the format rules using known information about the presence and absence of syntax elements to produce decoded video.

[0518] In the present disclosure, the term "video processing" may refer to video encoding, video decoding, video compression, or video decompression. For example, a video compression algorithm may be applied during the conversion from a pixel representation of a video to a corresponding bitstream representation, or vice versa. For example, the bitstream representation of a current video block may correspond to bits spread at the same position in the bitstream or at different positions as defined by the syntax. For example, a macroblock may be encoded based on a transformed and encoded error residual value, and bits in the header and other fields in the bitstream may also be used. Furthermore, during the conversion, the decoder may parse the bitstream based on this determination, knowing that some fields may or may not be present, as described in the above solution. Similarly, the encoder may determine whether to include or not include particular syntax fields, and generate the codec representation accordingly by including the syntax fields or excluding the syntax fields from the codec representation.

[0519] The disclosed and other solutions, examples, embodiments, modules, and functional operations described in this disclosure may 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 a combination of one or more thereof. The disclosed and other embodiments may 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 a data processing apparatus or to control the operation of the data processing apparatus. The computer-readable medium may be a machine-readable storage device, a machine-readable storage substrate, a storage device, a composition of matter that effects a machine-readable propagated signal, or a combination of one or more thereof. The term "data processing apparatus" includes all apparatus, devices, and machines for processing data, including, for example, a programmable processor, a computer, or multiple processors or computers. In addition to hardware, the apparatus may also include code that creates an execution environment for the associated computer program, such as code constituting processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more thereof. A propagated signal is an artificially generated signal, such as a machine-generated electrical, optical, or electromagnetic signal, that is generated to encode information for transmission to a suitable receiver device.

[0520] A computer program (also referred to as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including stand-alone programs or modules, components, subroutines, or other units suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored in a portion of a file preserving 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 collaborative files (e.g., files storing one or more modules, subroutines, or code portions). A computer program can be deployed to execute on one computer or on multiple computers, which are located at a site or distributed across multiple sites and interconnected by a communication network.

[0521] The processes and logic flows described in this disclosure may be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows may also be performed by, and the apparatus may be implemented as, special-purpose logic circuitry, such as a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC).

[0522] Processors suitable for executing computer programs include, for example, general-purpose and special-purpose microprocessors, as well as any one or more processors of any type of digital computer. Typically, a processor will receive instructions and data from read-only memory or random access memory, or both. The essential elements of a computer are a processor that executes instructions and one or more memory devices that store instructions and data. Typically, a computer will also include one or more mass storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks. However, a computer need not necessarily have such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and storage devices, including, for example, semiconductor memory devices, such as erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), and flash memory devices; magnetic disks, such as internal or removable hard disks; magneto-optical disks; and compact disc read-only memory (CDROM) and digital versatile disc read-only memory (DVD-ROM) disks. The processor and memory may be supplemented by, or incorporated into, dedicated logic circuitry.

[0523] Although this disclosure includes many details, these details should not be interpreted as limitations on any subject matter or the scope of the claims, but rather as descriptions of features unique to particular embodiments of the disclosure. In this disclosure, certain features described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately in multiple embodiments, or in any suitable subcombination. In addition, although features may function in certain combinations as described above, and may even be initially claimed in this manner, in some cases, one or more features in a claimed combination may be omitted from the combination, and the claimed combination may be directed to a subcombination or a variant of the subcombination.

[0524] Similarly, while operations are depicted in a particular order in the drawings, this should not be understood as requiring that such operations be performed sequentially in the particular order or sequence shown, or that all illustrated operations be performed to achieve desired results. Furthermore, the partitioning of various system components in the embodiments described in this disclosure should not be understood as requiring such partitioning in all embodiments.

[0525] Only a few implementations and examples are described, and other implementations, improvements, and variations can be made based on what is described and illustrated in this disclosure.

[0526] A first component is directly coupled to a second component when there are no intervening components (other than a line, trace, or other medium between the first and second components). A first component is indirectly coupled to a second component when there are intervening components other than a line, trace, or other medium between the first and second components. The term "coupled" and its variations include both direct and indirect couplings. The use of the term "about" is intended to include a range of ±10% of the subsequent number unless otherwise specified.

[0527] Although a number of embodiments are provided in this disclosure, it should be understood that the disclosed systems and methods may be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered illustrative rather than restrictive, and are not intended to be limited to the details given herein. For example, various elements or components may be combined or integrated in another system, or certain features may be omitted or not implemented.

[0528] In addition, the techniques, systems, subsystems, and methods described and illustrated as discrete or separate in various embodiments can be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of this disclosure. Other items shown or discussed as coupled can be directly connected, or can be indirectly coupled or communicated through some interface, device, or intermediate component (whether electrical, mechanical, or other). Examples of other changes, substitutions, and modifications can be determined by those skilled in the art and can be made without departing from the spirit and scope disclosed herein.

Claims

1. A method for processing media data, comprising: Determine the purpose of the neural network post-processing filter (NNPF) based on the neural network post-processing filter characteristic (NNPFC) supplemental enhancement information (SEI) message; as well as Performing conversion between visual media data and bitstream based on the NNPF object, wherein a plurality of input pictures are used for the NNPF purpose, and The NNPF is capable of selectively generating output images for some (multiple) input images, but not generating output images for other (multiple) input images.

2. The method according to claim 1, wherein The bitstream includes an indication that corresponding output pictures are to be generated for input picture(s).

3. The method according to any one of claims 1 to 2, wherein When the NNPF purpose is picture rate upsampling, an indication is included in the bitstream.

4. The method according to any one of claims 1 to 3, wherein The indication indicates whether one or more input pictures are interpolated and output by the NNPF.

5. The method according to any one of claims 1 to 4, wherein The indication includes a flag corresponding to each input picture, wherein the flag corresponding to a specific input picture has a first value indicating that a corresponding output picture is generated for the specific input picture, and the flag corresponding to the specific input picture has a second value indicating that a corresponding output picture is not generated for the specific input picture.

6. The method according to any one of claims 1 to 5, wherein The first value indicates that no corresponding output picture is generated for any input picture.

7. The method according to any one of claims 1 to 6, wherein The second value indicates that corresponding output pictures are generated for all input pictures.

8. The method according to any one of claims 1 to 7, wherein Indicating that the third value indicates that corresponding output pictures are generated for all input pictures except the first input picture in output order.

9. The method according to any one of claims 1 to 8, wherein Indicating a fourth value indicates that corresponding output pictures are generated for all input pictures except the last input picture in output order.

10. The method according to any one of claims 1 to 9, wherein When the NNPF purpose indicates that picture upsampling is not used, the indicated value is constrained to generate a corresponding output picture for at least one input picture.

11. The method according to any one of claims 1 to 10, wherein The indication is signaled in the NNPFC SEI message.

12. The method according to any one of claims 1 to 10, wherein The indication is signaled in the Neural Network Post-Processing Filter Activation (NNPFA) SEI message.

13. A device for processing video data, comprising: processor; and a non-transitory memory having instructions thereon, wherein the instructions, when executed by the processor, cause the processor to perform the method according to any one of claims 1-12.

14. A non-transitory computer-readable medium comprising: A computer program product for use with a video codec device, wherein the computer program product comprises computer executable instructions stored on the non-transitory computer-readable medium, so that when executed by a processor, the video codec device is caused to perform the method according to any one of claims 1 to 12.

15. A non-transitory computer-readable recording medium storing a bit stream of a video generated by a method performed by a video processing apparatus, wherein The method comprises: determining a neural network post-processing filter (NNPF) purpose based on a neural network post-processing filter characteristic (NNPFC) supplemental enhancement information (SEI) message; and generating a bitstream based on the determination, wherein a plurality of input pictures are used for the NNPF purpose, and The NNPF is capable of selectively generating output images for some (multiple) input images, but not generating output images for other (multiple) input images.

16. A method for storing a bitstream of a video, comprising: Determine the purpose of the neural network post-processing filter (NNPF) based on the neural network post-processing filter characteristic (NNPFC) supplemental enhancement information (SEI) message; generating a bitstream based on the determination; as well as storing the bitstream in a non-transitory computer-readable recording medium, wherein a plurality of input pictures are used for the NNPF purpose, and The NNPF is capable of selectively generating output images for some (multiple) input images, but not generating output images for other (multiple) input images.

Images