# US 10,484,708 B2 · Decoding method and apparatuses with candidate motion vectors > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,484,708 B2 - Document ID: US10484708B2 - Status: Granted - Kind: B2 - Application number: 16/135,900 - Filed: 2018-09-19 - Published: 2019-01-17 - Granted: 2019-11-19 - Earliest claimed: 2011-05-24 - Assignees: Velos Media, LLC - Applicants: Velos Media, LLC - Inventors: Toshiyasu Sugio; Takahiro Nishi; Youji Shibahara; Kyoko Tanikawa; Hisao Sasai; Toru Matsunobu - Web page: https://patentgrep.com/patent/US10484708B2 ## CPC - H04N 19/52: by predictive encoding - H04N 19/521: {for estimating the reliability of the determined motion vectors or motion vector field, e.g. for smoothing the motion vector field or for correcting motion vectors} - 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 19/176: the region being a block, e.g. a macroblock - H04N 19/463: by compressing encoding parameters before transmission - H04N 19/513: Processing of motion vectors - H04N 19/577: Motion compensation with bidirectional frame interpolation, i.e. using B-pictures - H04N 19/61: in combination with predictive coding - H04N 19/65: using error resilience - 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 image coding method bitstream includes: determining a maximum number of a merging candidate which is a combination of a prediction direction, a motion vector, and a reference picture index for use in coding of a current block; deriving a first merging candidate; determining whether or not a total number of the first merging candidate is smaller than the maximum number; deriving a second merging candidate when it is determined that the total number of the first merging candidate is smaller than the maximum number; selecting a merging candidate for use in the coding of the current block from the first merging candidate and the second merging candidate; and coding, using the maximum number, an index for identifying the selected merging candidate, and attaching the coded index to the bitstream. ## Claims ### Claim 1 An image decoding method, comprising: decoding information indicative of a fixed candidate number to be used for decoding a plurality of merge-mode blocks; and for a current block among the plurality of merge-mode blocks: deriving a plurality of first merging candidates, wherein each merging candidate is derived based on a combination of a prediction direction, a motion vector, and a reference picture index that has been used to decode a first block; determining whether or not a total number of first merging candidates is less than the fixed candidate number; when the total number of first merging candidates is less than the fixed candidate number, deriving at least one second merging candidate that is different from each of the first merging candidates until the total number of first merging candidates and second merging candidates is equal to the fixed candidate number, wherein each of the one or more second merging candidates has a different combination of a prediction direction, a motion vector, and a reference picture index from each of the first merging candidates; and decoding a coded index using the fixed candidate number regardless of the total number of first merging candidates, wherein the coded index corresponds to one of the plurality of first merging candidates or one of the at least one second merging candidate. ### Claim 2 (depends on 1) The image decoding method according to claim 1, further comprising: removing an identical candidate from the plurality of first merging candidates before determining whether or not the total number of first merging candidates is less than the fixed candidate number. ### Claim 3 (depends on 1) The image decoding method according to claim 1, further comprising: removing an unusable-for-merging candidate from the plurality of first merging candidates before determining whether or not the total number of first merging candidates is less than the fixed candidate number, wherein the unusable-for-merging candidate is a merging candidate that has been coded by intra prediction, that is outside a boundary of the slice or a picture including the current block, or that is yet to be coded. ### Claim 4 (depends on 1) The image decoding method according to claim 1, wherein decoding the coded index using the fixed candidate number is omitted when the fixed candidate number is one. ### Claim 5 (depends on 1) The image decoding method according to claim 1, wherein decoding the coded index using the fixed candidate number comprises decoding the coded index using variable-length coding based on the fixed candidate number. ### Claim 6 An image decoding apparatus comprising a processor and a memory, the processor, working together with the memory, being configured to: decode information indicative of a fixed candidate number to be used for decoding a plurality of merge-mode blocks; and for a current block among the plurality of merge-mode blocks: derive a plurality of first merging candidates, wherein each merging candidate is derived based on a combination of a prediction direction, a motion vector, and a reference picture index that has been used to decode a first block; determine whether or not a total number of first merging candidates is less than the fixed candidate number; when the total number of first merging candidates is less than the fixed candidate number, derive at least one second merging candidate that is different from each of the first merging candidates until the total number of first merging candidates and second merging candidates is equal to the fixed candidate number, wherein each of the one or more second merging candidates has a different combination of a prediction, a motion vector, and a reference picture index from each of the first merging candidates; and decode a coded index using the fixed candidate number regardless of the total number of first merging candidates, wherein the coded index corresponds to one of the plurality of first merging candidates or one of the at least one second merging candidate. ### Claim 7 (depends on 6) The image decoding apparatus according to claim 6, wherein the processor, working together with the memory, is further configured to: remove an identical candidate from the plurality of first merging candidates before determining whether or not the total number of first merging candidates is less than the fixed candidate number. ### Claim 8 (depends on 6) The image decoding apparatus according to claim 6, wherein the processor, working together with the memory, is further configured to: remove an unusable-for-merging candidate from the plurality of first merging candidates before determining whether or not the total number of first merging candidates is less than the fixed candidate number, wherein the unusable-for-merging candidate is a merging candidate that has been coded by intra prediction, that is outside a boundary of the slice or a picture including the current block, or that is yet to be coded. ### Claim 9 (depends on 6) The image decoding apparatus according to claim 6, wherein decoding the coded index using the fixed candidate number is omitted when the fixed candidate number is one. ### Claim 10 (depends on 6) The image decoding apparatus according to claim 6, wherein decoding the coded index using the fixed candidate number comprises decoding the coded index using variable-length coding based on the fixed candidate number.