US 12,231,654 B2
History-based motion vector prediction and mode selection for gradual decoding refresh
Seungwook Hong, San Diego, CA (US); Limin Wang, San Diego, CA (US); and Krit Panusopone, San Diego, CA (US)
Assigned to Nokia Technologies Oy, Espoo (FI)
Appl. No. 18/246,257
Filed by Nokia Technologies Oy, Espoo (FI)
PCT Filed Sep. 2, 2021, PCT No. PCT/EP2021/074206
§ 371(c)(1), (2) Date Mar. 22, 2023,
PCT Pub. No. WO2022/063538, PCT Pub. Date Mar. 31, 2022.
Claims priority of provisional application 63/084,360, filed on Sep. 28, 2020.
Prior Publication US 2023/0362390 A1, Nov. 9, 2023
Int. Cl. H04N 19/159 (2014.01); H04N 19/105 (2014.01); H04N 19/176 (2014.01); H04N 19/52 (2014.01)
CPC H04N 19/159 (2014.11) [H04N 19/105 (2014.11); H04N 19/176 (2014.11); H04N 19/52 (2014.11)] 20 Claims
OG exemplary drawing
 
1. An apparatus comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to:
obtain a current coding unit of a picture, the picture comprising a plurality of coding units including the current coding unit;
access information associated with the current coding unit, wherein the information comprises a History-Based Motion Vector Prediction (HMVP) table, wherein the HMVP table comprises an amount of coding unit references, each coding unit reference associated with a respective coding unit of the plurality of coding units that has previously undergone an inter coding operation;
determine at least one candidate coding unit reference of the predefined amount of coding unit references based at least upon a comparison of an index value associated with the at least one candidate coding unit reference to a dirty index, the dirty index comprising an index value of a coding unit of the plurality of coding units last to have undergone an inter coding operation while within a dirty area of the picture;
assign at least one coding unit associated with the at least one candidate coding unit reference to a candidate list for selection in a coding process for the current coding unit; and
prevent a candidate coding unit in the candidate list from being selected in the coding process for the current coding unit: (i) in an instance in which the current coding unit is within a coding tree unit having both a clean area and a dirty area, or (ii) for the picture in its entirety or the current coding unit in a clean area of the picture in an instance in which an associated virtual boundary is not aligned with the coding tree unit.