# US 2018/0324457 A1 · Encoding device, encoding method, and storage medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0324457 A1 - Document ID: US20180324457A1 - Status: Published application - Kind: A1 - Application number: 15/966,057 - Filed: 2018-04-30 - Published: 2018-11-08 - Earliest claimed: 2017-05-02 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Takafumi Murata - Web page: https://patentgrep.com/patent/US20180324457A1 ## CPC - H04N 19/577: Motion compensation with bidirectional frame interpolation, i.e. using B-pictures - 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 19/114: Adapting the group of pictures [GOP] structure, e.g. number of B-frames between two anchor frames (H04N19/107 takes precedence) - H04N 19/137: Motion inside a coding unit, e.g. average field, frame or block difference - H04N 19/172: the region being a picture, frame or field - H04N 19/30: using hierarchical techniques, e.g. scalability (H04N19/63 takes precedence) - H04N 19/573: Motion compensation with multiple frame prediction using two or more reference frames in a given prediction direction - H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract An encoding device that performs an encoding process on a moving image by using motion estimation according to the present invention includes: an acquisition unit that acquires a framerate of the moving image; a setting unit that performs setting of the number of reference frames on each frame of the moving image in accordance with the framerate; and an estimation unit that performs the motion estimation by using a frame to be encoded and a reference frame acquired based on the setting, and the setting unit performs the setting such that the number of reference frames is smaller when the framerate is higher. ## Claims ### Claim 1 An encoding device that performs an encoding process on a moving image by using motion estimation, the encoding device comprising: an acquisition unit that acquires a framerate of the moving image; a setting unit that performs setting of the number of reference frames on each frame of the moving image in accordance with the framerate; and an estimation unit that performs the motion estimation by using a frame to be encoded and a reference frame acquired based on the setting, wherein the setting unit performs the setting such that the number of reference frames is smaller when the framerate is higher. ### Claim 2 (depends on 1) The encoding device according to claim 1, wherein, when the framerate is higher, the setting unit increases a ratio of frames of the moving image for which the setting is performed. ### Claim 3 (depends on 1) The encoding device according to claim 1 further comprising a selection unit that selects a reference frame used in the motion estimation with priority on a reference frame having a smaller temporal distance to the frame to be encoded. ### Claim 4 The encoding device according to claim wherein the setting unit performs the setting such that the number of reference frames is one when the framerate is higher than a predetermined threshold. ### Claim 5 (depends on 1) The encoding device according to claim 1, wherein the setting unit performs the setting such that an encoding process of each frame for the moving image is completed within one frame period. ### Claim 6 (depends on 5) The encoding device according to claim 5, wherein the setting unit performs the setting taking into consideration of a firmware process in which process time per frame is constant. ### Claim 7 (depends on 1) The encoding device according to claim 1 further comprising a second selection unit that, out of a plurality of reference frames categorized into a plurality of hierarchies in accordance with a code amount, selects a reference frame used for motion estimation with the frame to be encoded with prioritization on a reference frame belonging to a higher hierarchy in which the code amount is larger. ### Claim 8 (depends on 7) The encoding device according to claim 7, wherein the second selection unit selects an I-frame on which the motion estimation is not performed, a P-frame on which forward estimation is performed in the motion estimation, and a B-frame on which bidirectional estimation is performed in the motion estimation in this order out of reference frames categorized into the same hierarchy. ### Claim 9 (depends on 8) The encoding device according to claim 8, wherein the hierarchies are represented using a temporal identifier in High Efficiency Video Coding (HEVC). ### Claim 10 An encoding method of a moving image using motion estimation, the encoding method comprising steps of: acquiring a framerate of the moving image; performing setting of the number of reference frames on each frame of the moving image in accordance with the framerate; and performing the motion estimation by using a frame to be encoded and a reference frame acquired based on the setting, wherein the number of reference frames is set to be smaller when the framerate is higher. ### Claim 11 (depends on 1) A non-transitory storage medium including a program that causes a computer to function as each of the units of the encoding device according to claim 1.