# US 2021/0243430 A1 · Method and apparatus for combined intra prediction modes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0243430 A1 - Document ID: US20210243430A1 - Status: Published application - Kind: A1 - Application number: 17/049,724 - Filed: 2019-04-03 - Published: 2021-08-05 - Earliest claimed: 2018-04-27 - Assignees: InterDigital VC Holdings, Inc. - Applicants: Interdigital Vc Holdings, Inc. - Inventors: Franck GALPIN; Fabien RACAPE; Philippe BORDES; Fabrice URBAN - Web page: https://patentgrep.com/patent/US20210243430A1 ## CPC - H04N 19/105: Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction - H04N 19/593: involving spatial prediction techniques - H04N 19/11: among a plurality of spatial predictive coding modes - 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 19/197: {including determination of the initial value of an encoding parameter (H04N19/56 takes precedence)} - H04N 19/463: by compressing encoding parameters before transmission - H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Encoders and decoders of digital video signals use combined intra prediction modes for some images. In at least one embodiment, combined intra prediction modes can result from the intra prediction modes of neighboring blocks. The combined intra prediction mode can be added to a most probable modes list. Various embodiments describe techniques for combining the intra prediction modes, comprising a combination of reference samples and a combination of directions to form a prediction. Another embodiment adds a combination mode to the most probable modes list if the two modes that are combined to form it are directional modes with angle difference less than 90 degrees. Another embodiment uses a linear combination of intra prediction modes and another embodiment performs a linear combination which depends on the distance of a prediction from the left and above blocs. ## Claims ### Claim 1 A method, comprising: predicting a current video block based on a combination of intra prediction modes from video blocks neighboring the current video block; and encoding the current video block using said prediction, wherein said combination of intra prediction modes is added to a list of most probable modes used during encoding, wherein a new combination mode is added to the list of most probable modes when neighboring modes are checked and said new combination mode is possible. ### Claim 2 An apparatus for encoding a block of image data, comprising: a memory, and a processor, configured to: predict a current video block based on a combination of intra prediction modes from video blocks neighboring the current video block; and encode the current video block using said prediction, wherein said combination of intra prediction modes is added to a list of most probable modes used during encoding, wherein a new combination mode is added to the list of most probable modes when neighboring modes are checked and said new combination mode is possible. ### Claim 3 A method, comprising: predicting a current video block based on a combination of intra prediction modes from video blocks neighboring the current video block; and decoding the current video block using said prediction, wherein said combination of intra prediction modes is added to a list of most probable modes used during decoding, wherein a new combination mode is added to the list of most probable modes when neighboring modes are checked and said new combination mode is possible. ### Claim 4 An apparatus for decoding a block of image data, comprising: a memory, and a processor, configured to: predict a current video block based on a combination of intra prediction modes from video blocks neighboring the current video block; and decode the current video block using said prediction, wherein said combination of intra prediction modes is added to a list of most probable modes used during decoding, wherein a new combination mode is added to the list of most probable modes when neighboring modes are checked and said new combination mode is possible. ### Claim 5 (depends on 3) The method of claim 3, wherein said combination of intra prediction modes is added to said list of most probable modes if the modes from said combination of intra prediction modes of video blocks neighboring the current block are different. ### Claim 6 (depends on 3) The method of claim 3, wherein a syntax element specifies use of a most probable modes list and wherein an index of most probable modes corresponds to a combination of intra prediction modes from video blocks neighboring the current video block. ### Claim 7 (depends on 3) The method of claim 3, wherein a combination of intra prediction modes is an additional mode in a list of most probable modes. ### Claim 8 (depends on 3) The method of claim 3, wherein a mode is added to the list of most probable modes for a subset of possible combinations. ### Claim 9 (depends on 8) The method of claim 8, wherein said subset comprises modes from a block to the left and above that of a current video block. ### Claim 10 (depends on 3) The method of claim 3, a combined mode is added to a list of most probable modes if it is based on directional intra modes with an angle difference of less than 90 degrees. ### Claim 11 (depends on 3) The method of claim 3, wherein said combination is a linear combination of sample values when predicted with different modes. ### Claim 12 (depends on 3) The method of claim 3, wherein said combination is formed based on direction. ### Claim 13 (depends on 1) A non-transitory computer readable medium containing data content generated according to the method of claim 1, for playback using a processor. ### Claim 14 (depends on 1) A signal comprising video data generated according to the method of claim 1, for playback using a processor. ### Claim 15 (depends on 3) A computer program product comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method of claim 3.