Adaptation parameter set types in video coding

A method implemented by an encoder, the method comprising:

• encoding a slice into a bitstream as a coded slice as part of an encoded video sequence;
• determining adaptive loop filter (ALF) parameters associated with the coded slice;
• encoding the ALF parameters into the bitstream in a first adaptation parameter set (APS) network abstraction layer (NAL) unit including an ALF type;
• and
• storing 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, and 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 video coding device comprising:

• a receiver configured to receive a bitstream comprising 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;
• and
• a processor coupled to the receiver and configured to:
• obtain ALF parameters from the first APS NAL unit;
• and
• 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 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, and 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.