# US 2021/0344905 A1 · Method and apparatus for candidate list pruning > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0344905 A1 - Document ID: US20210344905A1 - Status: Published application - Kind: A1 - Application number: 17/373,927 - Filed: 2021-07-13 - Published: 2021-11-04 - Earliest claimed: 2017-05-31 - Assignees: InterDigital VC Holdings, Inc. - Applicants: Interdigital Vc Holdings, Inc. - Inventors: Fabien RACAPE; Franck GALPIN; Antoine ROBERT - Web page: https://patentgrep.com/patent/US20210344905A1 ## 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 19/176: the region being a block, e.g. a macroblock - H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) - H04N 19/52: by predictive encoding - H04N 19/523: with sub-pixel accuracy - H04N 19/577: Motion compensation with bidirectional frame interpolation, i.e. using B-pictures - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Video signal coding and decoding functions can generate lists of potential candidates to use in coding and decoding, for example, predictors. Video signal coding component candidate undergo operations before potential inclusion in candidate lists. The candidates are checked after being modified by the operations to see if other equal candidates are already in the candidate list. If equal candidates are not in the list, the modified candidates are added to the candidate list. If equal candidates are already in the list, the modified candidates are not added to the list. Operations that can be performed comprise rounding and clipping. ## Claims ### Claim 1 A method, comprising: encoding a video signal using a candidate list by: performing all motion vector rounding operations on an advanced motion vector prediction motion vector to generate at least one modified candidate; determining whether said at least one modified candidate is present in the candidate list; adding said at least one modified candidate to the candidate list if said at least one modified candidate is not present in the candidate list or not adding said at least one modified candidate to the candidate list if said at least one modified candidate is present in the candidate list. ### Claim 2 A method, comprising: decoding a video signal, comprising: performing all motion vector rounding operations on an advanced motion vector prediction motion vector to generate at least one modified candidate; determining whether said at least one modified candidate is present in a candidate list; adding said at least one modified candidate to the candidate list if said at least one modified candidate is not present in the candidate list or not adding said at least one modified candidate to the candidate list if said at least one modified candidate is present in the candidate list. ### Claim 3 An apparatus, comprising: a memory, and a processor configured to encode a video signal using a candidate list by: performing all motion vector rounding operations on an advanced motion vector prediction motion vector to generate at least one modified candidate; determining whether said at least one modified candidate is present in the candidate list; adding said at least one modified candidate to the candidate list if said at least one modified candidate is not previously present in the candidate list or not adding said at least one modified candidate to the candidate list if said at least one modified candidate is present in the candidate list. ### Claim 4 An apparatus, comprising: a memory, and a processor configured to decode a video signal using a candidate list by: performing all motion vector rounding operations on an advanced motion vector prediction motion vector to generate at least one modified candidate; determining whether said at least one modified candidate is present in the candidate list; adding said at least one modified candidate to the candidate list if said at least one modified candidate is not previously present in the candidate list or not adding said at least one modified candidate to the candidate list if said at least one modified candidate is present in the candidate list. ### Claim 5 (depends on 1) The method of claim 1, wherein said at least one operation comprises clipping, rounding, and selecting a different candidate. ### Claim 6 (depends on 1) The method of claim 1, wherein said video signal coding component candidate comprises at least one of motion vector, reference blocks, reference frames, reference frame index, and a reference frame list. ### Claim 7 (depends on 1) The method of claim 1, wherein said at least one operation comprises rounding motion vectors to one-quarter pixel resolution and integer motion vector rounding of both predictors in an Advanced Motion Vector Prediction process. ### Claim 8 (depends on 7) The method of claim 7, wherein a second motion vector is obtained in an area not considered as a candidate for a first motion vector. ### Claim 9 (depends on 1) The method of claim 1, wherein a merge predictor comprising a motion vector, a reference frame index, a reference frame list and an IC flag, are the candidates to be added to said candidate list if not previously present in said candidate list. ### Claim 10 (depends on 1) The method of claim 1, wherein candidates in a frame rate up conversion process are found, comprising a motion vector, a reference frame index, and a reference frame list. ### Claim 11 (depends on 1) A non-transitory computer readable medium containing data content generated according to the method of claim 1, for playback. ### Claim 12 (depends on 2) 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 2. ### Claim 13 (depends on 3) The apparatus of claim 3, wherein said at least one operation comprises clipping, rounding, and selecting a different candidate. ### Claim 14 (depends on 4) The apparatus of claim 4, wherein said at least one operation comprises clipping, rounding, and selecting a different candidate.