US 12,355,961 B2
Adaptive loop filter
Jonathan Taquet, Talensac (FR); Christophe Gisquet, Acigne (FR); Guillaume Laroche, Saint Aubin d'Aubigné (FR); and Patrice Onno, Rennes (FR)
Assigned to Canon Kabushiki Kaisha, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on May 1, 2024, as Appl. No. 18/652,710.
Application 18/652,710 is a continuation of application No. 17/434,361, granted, now 11,991,353, previously published as PCT/EP2020/055888, filed on Mar. 5, 2020.
Claims priority of application No. 1903187 (GB), filed on Mar. 8, 2019; application No. 1903584 (GB), filed on Mar. 15, 2019; application No. 1908937 (GB), filed on Jun. 21, 2019; and application No. 1919037 (GB), filed on Dec. 20, 2019.
Prior Publication US 2024/0348779 A1, Oct. 17, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. H04N 19/117 (2014.01); H04N 19/176 (2014.01); H04N 19/186 (2014.01); H04N 19/46 (2014.01); H04N 19/82 (2014.01)
CPC H04N 19/117 (2014.11) [H04N 19/176 (2014.11); H04N 19/186 (2014.11); H04N 19/46 (2014.11); H04N 19/82 (2014.11)] 19 Claims
OG exemplary drawing
 
11. A device for encoding image data, the device comprising:
an encoder which encodes image data into a bitstream; and
an Adaptive Loop Filter which filters image data, the Adaptive Loop Filter comprising:
a data obtainer which, for a slice containing one or more coding tree blocks, obtains data indicating a number of alternative chroma filters for Adaptive Loop Filtering, wherein the number can be more than one;
a limiter which imposes a limit of 8 on a maximum allowed number of alternative chroma filters which may be indicated by the obtained data;
an index obtainer which, for a coding tree block in the slice containing one or more coding tree blocks, obtains an alternative filter index identifying one of the one or more available alternative chroma filters, the number of which is indicated by the data; and
a selector which selects the one of the one or more alternative chroma filters identified by the alternative filter index to filter chroma image data in the coding tree block,
wherein the Adaptive Loop Filter further comprises,
a flag obtainer which obtains a flag for the one or more alternative chroma filters, the flag indicating whether a chroma filter is a linear filter or a non-linear filter; and
a clipping value indices obtainer which obtains one or more clipping value indices for the one or more alternative chroma filters when the obtained flag indicates that a chroma filter is a non-linear filter,
wherein a clipping value index for Adaptive Loop Filtering in the one or more clipping value indices of a non-linear filter indicates a clipping value used for a coefficient of a chroma filter in the one or more chroma filters.