# US 8,787,441 B2 · Device and method for coding and decoding video data and data train > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,787,441 B2 - Document ID: US8787441B2 - Status: Granted - Kind: B2 - Application number: 11/988,407 - Filed: 2006-07-05 - Published: 2009-11-12 - Granted: 2014-07-22 - Earliest claimed: 2005-07-07 - Assignees: Thomson Licensing - Applicants: Frédéric Pasquier; Sylvain Fabre; Bruno Garnier - Inventors: Frédéric Pasquier; Sylvain Fabre; Bruno Garnier - Web page: https://patentgrep.com/patent/US8787441B2 ## CPC - H04N 19/107: between spatial and temporal predictive coding, e.g. picture refresh - H04N 19/172: the region being a picture, frame or field - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/177: the unit being a group of pictures [GOP] - H04N 19/196: being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters (processing of motion vectors H04N19/513) - H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) - H04N 19/61: in combination with predictive coding - H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract The invention relates to a device for coding video data comprising means to code a video stream as groups of pictures, each group of pictures comprising at least one description unit relevant to the coding of the said group of pictures. According to the invention, the coding device comprises means to insert in the stream of data at least one message indicating whether the description unit of the current group of pictures is identical to the description unit relevant to the preceding group of pictures. The invention also relates to a device for decoding video data comprising means to decode a stream of data coded with a device according to one of the preceding claims. According to the invention, the decoding device comprises means to analyze the said messages, means to decode the at least one next description unit if the said message indicates that this unit is different from the preceding description unit, otherwise, if it is identical, not to decode it. ## Claims ### Claim 1 Device for coding video data comprising means to code a video stream as groups of pictures, each group of pictures comprising a unit of a first type, at least one unit of a second type and a plurality of units of a fourth type, wherein said unit of the first type comprises at least one message, wherein said at least one unit of the second type is at least one description unit comprising parameters relative to coding of said group of pictures, wherein said plurality of units of the fourth type comprise data relative to the coded group of pictures, and wherein said device comprises: means to insert in the stream of data, before said at least one description unit of a current group of pictures, in said unit of the first type, said at least one message, wherein the at least one message indicates whether said parameters relative to the current group of pictures included in the at least one description unit of the current group of pictures are identical to parameters relative to a temporally preceding group of pictures included in a corresponding preceding description unit. ### Claim 2 (depends on 1) Coding device according to claim 1 wherein the means to insert the at least one message inserts the at least one message in said unit of the first type at the start of each group of pictures. ### Claim 3 (depends on 1) Coding device according to claim 1 wherein each group of pictures comprises two description units for each group of pictures, the first of the said description units comprising parameters relative to the coding mode used for each picture of the group and the second description unit comprising parameters relative to coding parameters used by the coding device and wherein a first message of said group of pictures is set when the parameters of said first description unit are identical to the parameters of said first description units of the preceding group of pictures and said first message of said group of pictures is reset when the parameters of said first description unit are different from the parameters of said first description units of the preceding group of pictures and wherein a second message of said group of pictures is set when the parameters of said second description unit are identical to the parameters of said second description units of the preceding group of pictures and said second message of said group of pictures is reset when the parameters of said second description unit are different from the parameters of said second description units of the preceding group of pictures. ### Claim 4 (depends on 1) Coding device according to claim 1 wherein it comprises means of recording at least one of the said description units, intended to record at least one description unit when it is new with respect to the description unit of the preceding group of pictures. ### Claim 5 (depends on 1) Coding device according to claim 1 wherein it complies with the H264 coding standard. ### Claim 6 (depends on 5) Coding device according to claim 5 wherein said unit of the first type is of SEI type. ### Claim 7 (depends on 1) Device according to claim 1, wherein the said at least one message indicates for each description unit which of the description units is identical to the corresponding description unit comprising parameters relative to the preceding group of pictures. ### Claim 8 Method for coding video data coding a stream of pictures as groups of pictures, each group of pictures comprising a unit of a first type, at least one unit of a second type and a plurality of units of a fourth type, wherein said unit of the first type comprises at least one message, wherein said at least one unit of the second type is at least one description unit comprising parameters relative to coding of the said group of pictures, wherein said plurality of units of the fourth type comprise data relative to the coded group of pictures, and wherein the method comprises a step of insertion into the stream of data, before said at least one description unit in said unit of the first type of a current group of pictures, of the at least one message, wherein said at least one message indicates whether the parameters relative to the current group of pictures included in the description unit of the current group of pictures are identical to the parameters relative to a temporally preceding group of pictures included in a corresponding preceding description unit. ### Claim 9 (depends on 1) Device for decoding video data comprising means to decode a stream of data coded with a device according to claim 1, wherein it comprises means to analyse the at least one message, means to decode the at least one next description unit if the at least one message indicates that this unit is different from the preceding description unit, otherwise, if it is identical, not to decode it. ### Claim 10 (depends on 9) Decoding device according to claim 9 wherein it comprises means of recording at least one of the said description units, intended to record at least one description unit received when it is new. ### Claim 11 (depends on 1) Method for decoding video data coded with a device according to claim 1, wherein it comprises the steps of analysis of the at least one message, of decoding of the at least one description unit if the at least one message indicates that this unit is different from the preceding description unit, otherwise, if it is identical, of non-decoding of this unit. ### Claim 12 A non-transitory signal medium comprising a digital data train stored on the medium, said digital data train including digital data groups, each group comprising a unit of a first type, at least one unit of a second type and a plurality of units of a fourth type, wherein said unit of the first type comprises a message, wherein said at least one unit of the second type is at least one description unit comprising parameters relative to coding of the said group of pictures, wherein said plurality of units of the fourth type comprise data relative to the coded group of pictures, and wherein the message of said unit of the first type indicates whether the at least one description unit is identical or different from the at least one description unit of a temporally preceding group.