Adaptation Parameter Set Types in Video Coding

An encoder comprising:

• a processor configured to:
• encode a slice into a bitstream as a coded slice as part of an encoded video sequence;
• determine adaptive loop filter (ALF) parameters associated with the coded slice;
• and
• encode the ALF parameters into the bitstream in a first adaptation parameter set (APS) network abstraction layer (NAL) unit including an ALF type;
• and
• a memory coupled to the processor and configured to store the bitstream for communication toward a decoder,
• wherein the bitstream further comprises a third APS NAL unit including a luma mapping with chroma scaling (LMCS) type including LMCS parameters for application to the coded slice,
• wherein the bitstream comprises an ALF APS assigned to the first APS NAL unit and a LMCS APS assigned to the third APS NAL unit, wherein each APS includes an APS identifier (ID) from a predefined range determined based on a parameter type of each APS, wherein the APS is a syntax structure used to signal information for slices, wherein the LMCS parameters are used for a LMCS which is a process that scale chroma values based on luma mappings, wherein the ALF parameters are used for an ALF which is a filter controlled by parameters included in the ALF APS, and
• wherein the APSs of a particular type share a same value space for the APS IDs, and different types of the APSs use different value spaces of the APS ID.

A non-transitory storage medium storing an encoded bitstream for video signals, wherein the bitstream comprises a first adaptation parameter set (APS) network abstraction layer (NAL) unit including an adaptive loop filter (ALF) type, wherein the first APS NAL unit is referenced by a coded slice,

• wherein the bitstream comprises information to obtain ALF parameters from the first APS NAL unit,
• wherein the bitstream further comprises information to decode the coded slice using the ALF parameters,
• wherein the bitstream further comprises a third APS NAL unit including a luma mapping with chroma scaling (LMCS) type, and wherein LMCS parameters are obtained from the third APS NAL unit, wherein the coded slice is further decoded using the LMCS parameters,
• wherein the bitstream further comprises an ALF APS assigned to the first APS NAL unit and a LMCS APS assigned to the third APS NAL unit, wherein each APS includes an APS identifier (ID) from a predefined range determined based on a parameter type of each APS, wherein the APS is a syntax structure used to signal information for slices, wherein the LMCS parameters are used for a LMCS which is a process that scale chroma values based on luma mappings, wherein the ALF parameters are used for an ALF which is a filter controlled by parameters included in the ALF APS, and
• wherein the APSs of a particular type share a same value space for the APS IDs, and different types of the APSs use different value spaces of the APS ID.