US 12,309,409 B2
ALF APS constraints in video coding
Jianle Chen, San Diego, CA (US); and Fnu Hendry, San Diego, CA (US)
Assigned to Huawei Technologies Co., Ltd., Shenzhen (CN)
Filed by Huawei Technologies Co., Ltd., Shenzhen (CN)
Filed on Feb. 7, 2022, as Appl. No. 17/666,307.
Application 17/666,307 is a continuation of application No. PCT/US2020/041666, filed on Jul. 10, 2020.
Claims priority of provisional application 62/888,267, filed on Aug. 16, 2019.
Prior Publication US 2022/0159285 A1, May 19, 2022
Int. Cl. H04N 19/46 (2014.01); H04N 19/117 (2014.01); H04N 19/169 (2014.01); H04N 19/186 (2014.01); H04N 19/82 (2014.01)
CPC H04N 19/46 (2014.11) [H04N 19/117 (2014.11); H04N 19/186 (2014.11); H04N 19/188 (2014.11); H04N 19/82 (2014.11)] 12 Claims
OG exemplary drawing
 
1. A method implemented by a decoder, the method comprising:
receiving a bitstream comprising encoded video data for a slice and an adaptation parameter set (APS), wherein the APS comprises an APS identifier (adaptation_parameter_set_id) and an APS parameters type (aps_params_type), wherein the adaptation_parameter_set_id specifies an identifier for the APS, the aps_params_type specifies a type of parameter that is contained in the APS, wherein when the aps_params_type is equal to adaptive loop filter (ALF) APS (ALF_APS), the APS comprises an ALF and is an ALF APS, wherein the ALF APS comprises an ALF luma filter signal flag (alf_luma_filter_signal_flag) and an ALF chroma filter signal flag (alf_chroma_filter_signal_flag), wherein a value of the alf_luma_filter_signal_flag of an APS network abstraction layer (NAL) unit having the aps_params_type equal to ALF_APS and the adaptation_parameter_set_id equal to slice ALF APS identifier luma (slice_alf_aps_id_luma[i]) is constrained to be equal to one, wherein a value of the alf_chroma_filter_signal_flag of the APS NAL unit having the aps_params_type equal to ALF_APS and the adaptation_parameter_set_id equal to slice ALF APS identifier chroma (slice_alf_aps_id_chroma) is constrained to be equal to one, wherein slice_alf_aps_id_luma[i] specifies an adaptation_parameter_set_id of an i-th ALF APS referred to by a luma component of the slice, and wherein slice_alf_aps_id_chroma specifies the adaptation_parameter_set_id of the ALF APS referred to by a chroma component of the slice;
decoding a luma filter set when the alf_luma_filter_signal_flag specifies the luma filter set is signaled in the ALF APS;
decoding a chroma filter set when the alf_chroma_filter_signal_flag specifies the chroma filter set is signaled in the ALF APS; and
decoding the slice based on ALF parameters in the ALF APS, wherein the ALF parameters comprise the luma filter set or the chroma filter set.