# US 10,873,759 B2 · Data encoding and decoding > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,873,759 B2 - Document ID: US10873759B2 - Status: Granted - Kind: B2 - Application number: 15/127,815 - Filed: 2015-03-27 - Published: 2017-04-06 - Granted: 2020-12-22 - Earliest claimed: 2014-03-28 - Assignees: Sony Corporation - Applicants: Sony Corporation - Inventors: Karl James Sharman; James Alexander Gamei - Web page: https://patentgrep.com/patent/US10873759B2 ## CPC - H04N 19/55: Motion estimation with spatial constraints, e.g. at image or region borders - H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction - H04N 19/523: with sub-pixel accuracy - H04N 19/567: Motion estimation based on rate distortion criteria - H04N 19/57: Motion estimation characterised by a search window with variable size or shape - H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A method encoding image data including: encoding the image data by an inter-image predictor in which a block of one or more samples of a current image is predicted from a reference block of samples located at one of a number of candidate block positions in a reference image; and selectively applying a constrained inter-image prediction mode in which, in comparison to an inter-image prediction mode for the encoding, one or both of the number of candidate block positions and the number of candidate reference images is reduced. ## Claims ### Claim 1 A method of encoding image data comprising: encoding first portions of the image data to be included in a data stream of encoded image data by applying an inter-image prediction mode to the first portions of the image data in which a block of one or more samples of a current image is predicted from a reference block of samples located at one of a number of candidate reference block positions in a reference image of a number of candidate reference images; encoding second portions of the image data to be included in the data stream of encoded image data by applying a constrained inter-image prediction mode to the second portions of the image data in which, in comparison to the inter-image prediction mode, the number of candidate reference images is reduced while still predicting the block in the current image from the reference block in the reference image, and a motion vector is constrained to an integer value in the constrained inter-image prediction mode; and setting, in the data stream of encoded image data, a flag indicating the second portions of the image data to which the constrained inter-image prediction mode is applied. ### Claim 2 (depends on 1) The method according to claim 1, wherein the flag forms part of sequence parameter set data. ### Claim 3 (depends on 1) The method according to claim 1, wherein in the constrained inter-image prediction mode, a location in the reference image of the reference block is detected to a lower precision than in the inter-image prediction mode. ### Claim 4 (depends on 1) The method according to claim 1, wherein in the constrained inter-image prediction mode, the number of candidate reference blocks for use with the current image is smaller than the number of candidate reference blocks in the inter-image prediction mode. ### Claim 5 (depends on 1) The method according to claim 1, wherein in the constrained inter-image prediction mode, a position of the reference block in the reference image is identical to a position of the block in the current image. ### Claim 6 (depends on 1) The method according to claim 1, wherein in the constrained inter-image prediction mode, the number of candidate reference images for the current image is equal to one. ### Claim 7 (depends on 6) The method according to claim 6, wherein the one candidate reference image is an immediately temporally preceding image. ### Claim 8 (depends on 1) The method according to claim 1, further comprising: detecting the reference block by comparing the block of the current image with multiple candidate reference block positions in a search area of one or more candidate reference images. ### Claim 9 (depends on 1) The method according to claim 1, wherein in the constrained inter-image prediction mode, a search area of the reference image comprising the candidate reference block positions of the reference block is smaller than a search area of the reference image comprising the candidate reference block positions of the reference block in the inter-image prediction mode. ### Claim 10 (depends on 1) The method according to claim 1, wherein the motion vector is constrained to zero. ### Claim 11 A method of decoding image data, comprising: decoding, from a data stream of encoded image data, first portions of the image data by applying an inter-image prediction mode to the first portions of the image data in which a block of one or more samples of a current image is predicted from a reference block of samples located at one of a number of candidate reference block positions in a reference image of a number of candidate reference images; obtaining, from the data stream of encoded image data, a flag indicating second portions of the image data to which a constrained inter-image prediction mode is applied; and decoding, from the data stream of encoded image data, the second portions of the image data as indicated by the flag by applying the constrained inter-image prediction mode to the second portions of the image data in which, in comparison to the inter-image prediction mode, the number of candidate reference images is reduced while still predicting the block in the current image from the reference block in the reference image, and a motion vector is constrained to an integer value in the constrained inter-image prediction mode. ### Claim 12 (depends on 11) The method according to claim 11, wherein in the constrained inter-image prediction mode, a position of the reference block in the reference image is identical to a position of the block in the current image. ### Claim 13 (depends on 11) The method according to claim 11, wherein the flag forms part of sequence parameter set data. ### Claim 14 (depends on 1) A non-transitory, machine-readable storage medium which stores computer software which, when executed by a computer, causes the computer to carry out the method of claim 1. ### Claim 15 A data encoding apparatus comprising: circuitry configured to encode first portions of image data to be included in a data stream of encoded image data by applying an inter-image prediction mode to the first portions of the image data in which a block of one or more samples of a current image is predicted from a reference block of samples located at one of a number of candidate reference block positions in a reference image of a number of candidate reference images; encode second portions of the image data to be included in the data stream of encoded image data by applying a constrained inter-image prediction mode to the second portions of the image data in which, in comparison to the inter-image prediction mode, the number of candidate reference images is reduced while still predicting the block in the current image from the reference block in the reference image, and a motion vector is constrained to an integer value in the constrained inter-image prediction mode; and set, in the data stream of encoded image data, a flag indicating the second portions of the image data to which the constrained inter-image prediction mode is applied. ### Claim 16 (depends on 15) The data encoding apparatus of claim 15, wherein in the constrained inter-image prediction mode, a position of the reference block in the reference image is identical to a position of the block in the current image. ### Claim 17 A data decoding apparatus comprising: circuitry configured to decode, from a data stream of encoded image data, first portions of image data by applying an inter-image prediction mode to the first portions of the image data in which a block of one or more samples of a current image is predicted from a reference block of samples located at one of a number of candidate reference block positions in a reference image of a number of candidate reference images; obtain, from the data stream of encoded image data, a flag indicating second portions of the image data to which a constrained inter-image prediction mode is applied; and decode, from the data stream of encoded image data, the second portions of the image data as indicated by the flag by applying the constrained inter-image prediction mode to the second portions of the image data in which, in comparison to the inter-image prediction mode, the number of candidate reference images is reduced while still predicting the block in the current image from the reference block in the reference image, and a motion vector is constrained to an integer value in the constrained inter-image prediction mode. ### Claim 18 (depends on 17) The data decoding apparatus of claim 17, wherein in the constrained inter-image prediction mode, a position of the reference block in the reference image is identical to a position of the block in the current image. ### Claim 19 (depends on 15) A video data capture, transmission, display, and/or storage apparatus comprising apparatus according to claim 15. ### Claim 20 (depends on 17) A video data capture, transmission, display, and/or storage apparatus comprising the apparatus according to claim 17.