# US 12,003,725 B2 · Signaling method for chroma intra prediction mode > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,003,725 B2 - Document ID: US12003725B2 - Status: Granted - Kind: B2 - Application number: 17/709,665 - Filed: 2022-03-31 - Published: 2022-07-14 - Granted: 2024-06-04 - Earliest claimed: 2020-05-18 - Assignees: Tencent America LLC - Applicants: Tencent America LLC - Inventors: Liang Zhao; Xin Zhao; Shan Liu - Web page: https://patentgrep.com/patent/US12003725B2 ## CPC - H04N 19/13: Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC] - G06Q 10/06313: {Resource planning in a project environment} - G06Q 50/04: Manufacturing - H04N 19/11: among a plurality of spatial predictive coding modes - H04N 19/132: Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking - H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/186: the unit being a colour or a chrominance component - H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) - H04N 19/463: by compressing encoding parameters before transmission - H04N 19/593: involving spatial prediction techniques - H04N 19/119: Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G06Q: INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR ## Abstract A method, computer program, and computer system is provided for encoding or decoding video data. Video data including a chroma component and a luma component is received. One or more contexts for entropy coding chroma intra prediction modes are identified based on a co-located luma block at one or more pre-defined positions. The video data is decoded based on the identified contexts. ## Claims ### Claim 1 A method of video encoding, executable by a processor, comprising: receiving video data comprising a chroma component and a luma component; setting one or more contexts for entropy coding chroma intra prediction modes corresponding to one or more co-located luma blocks at one or more pre-defined positions; signaling a first flag to indicate that a chroma intra prediction mode associated with a current chroma block is a chroma-from-luma (CfL) mode based on the one or more set contexts, wherein a first value of the first flag indicates that the one or more co-located luma blocks are coded in a directional mode, and wherein a second value of the first flag indicates that the one or more co-located luma blocks are not coded in the directional mode; and encoding the video data based on the one or more set contexts. ### Claim 2 (depends on 1) The method of claim 1, wherein the one or more pre-defined positions comprise one or more from among a middle position and a top-left corner of the current chroma block. ### Claim 3 (depends on 2) The method of claim 2, wherein the middle position of the current chroma block corresponds to the top-left corner of a chroma block. ### Claim 4 (depends on 1) The method of claim 1, further comprising: identifying one or more pre-defined sample positions; and identifying one or more intra prediction modes associated with the one or more pre-defined sample positions for predicting the one or more co-located luma blocks; and wherein the one or more set contexts are further based on a prediction mode from among the identified one or more intra prediction modes. ### Claim 5 (depends on 1) The method of claim 1, wherein the one or more set contexts is further based on the one or more chroma intra prediction modes including the chroma-from-luma mode. ### Claim 6 (depends on 4) The method of claim 4, wherein the one or more pre-defined sample positions include one or more corner samples and a center sample. ### Claim 7 (depends on 4) The method of claim 4, wherein the one or more pre-defined sample positions include four corner samples. ### Claim 8 (depends on 1) The method of claim 1, wherein the one or more set contexts is further based on one or more luma intra prediction modes associated with the one or more co-located luma blocks. ### Claim 9 (depends on 8) The method of claim 8, wherein the one or more set contexts includes a first context based on a determination that the one or more luma intra prediction modes include one or more directional modes. ### Claim 10 (depends on 8) The method of claim 8, wherein the one or more set contexts includes a second context based on a determination that at least one of the one or more luma intra prediction modes is a directional mode. ### Claim 11 (depends on 8) The method of claim 8, wherein the one or more set contexts includes a third context based on a determination that none of the one or more luma intra prediction modes is a directional mode. ### Claim 12 (depends on 5) The method of claim 5, wherein the one or more set contexts includes a second context based on a determination that at least one of the one or more chroma intra prediction modes is the chroma-from-luma mode. ### Claim 13 (depends on 1) The method of claim 1, wherein all nominal intra prediction angles allowed for luma coded blocks are allowed and signaled for chroma coded blocks. ### Claim 14 (depends on 13) The method of claim 13, wherein only a subset of delta angles to the nominal intra prediction angles are allowed and signaled for chroma intra coded blocks. ### Claim 15 (depends on 14) The method of claim 14, wherein all non-directional modes are allowed and signaled for chroma intra coded blocks. ### Claim 16 (depends on 14) The method of claim 14, wherein only delta angles corresponding to co-located luma intra prediction modes are allowed and signaled for the chroma coded blocks. ### Claim 17 (depends on 16) The method of claim 16, further comprising: signaling the nominal intra prediction angles together with the non-directional modes; and signaling, based on the chroma intra prediction mode associated with the current chroma block being the directional mode and equal to co-located luma nominal modes, a second flag to indicate an index of delta angle to the nominal intra prediction angles. ### Claim 18 (depends on 16) The method of claim 16, wherein all allowed intra prediction modes for the chroma coded blocks are signaled together. ### Claim 19 A computer system for encoding video data, the computer system comprising: one or more computer-readable non-transitory storage media configured to store computer program code; and one or more computer processors configured to access said computer program code and operate as instructed by said computer program code, said computer program code including: receiving code configured to cause the one or more computer processors to receive video data comprising a luma component and a chroma component; setting code configured to cause the one or more computer processors to set one or more contexts for entropy coding chroma intra prediction modes corresponding to one or more co-located luma blocks at one or more pre-defined positions; signaling code configured to cause the one or more computer processors to signal a first flag to indicate that a chroma intra prediction mode associated with a current chroma block is a chroma-from-luma mode (CfL) based on the one or more set contexts, wherein a first value of the first flag indicates that the one or more co-located luma blocks are coded in a directional mode, and wherein a second value of the first flag indicates that the one or more co-located luma blocks are not coded in the directional mode; and encoding code configured to cause the one or more computer processors to encode the video data based on the one or more set contexts. ### Claim 20 A non-transitory computer readable medium having stored thereon a computer program for encoding video data, the computer program configured to cause one or more computer processors to: receive video data comprising a luma component and a chroma component; set one or more contexts for entropy coding chroma intra prediction modes corresponding to one or more co-located luma blocks at one or more pre-defined positions; signal a first flag to indicate that a chroma intra prediction mode associated with a current chroma block is a chroma-from-luma mode based on the one or more set contexts, wherein a first value of the first flag indicates that the one or more co-located luma blocks are coded in a directional mode, and wherein a second value of the first flag indicates that the one or more co-located luma blocks are not coded in the directional mode; and encode the video data based on the one or more set contexts.