Restrictions on adaptive-loop filtering parameter sets

An apparatus for processing video data comprising a processor and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to:

• perform a conversion between a first video data unit with a first temporal layer index of a video and a bitstream of the video,
• wherein a first coding tool is applicable to a first video block of the first video data unit, wherein the first coding tool comprises, based on a first side information related to the first coding tool, processing the first video block based on a filtering process using adaptive loop filter coefficients, and
• wherein the first side information is determined based on one or more first adaptation parameter sets for the first coding tool, and wherein the one or more first adaptation parameter sets are associated with a second temporal layer index which is less than or equal to the first temporal layer index.

A non-transitory computer-readable storage medium storing instructions that cause a processor to:

• perform a conversion between a first video data unit with a first temporal layer index of a video and a bitstream of the video,
• wherein a first coding tool is applicable to a first video block of the first video data unit, wherein the first coding tool comprises, based on a first side information related to the first coding tool, processing the first video block based on a filtering process using adaptive loop filter coefficients, and
• wherein the first side information is determined based on one or more first adaptation parameter sets for the first coding tool, and wherein the one or more first adaptation parameter sets are associated with a second temporal layer index which is less than or equal to the first temporal layer index.

A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises:

• generating the bitstream based on a first video data unit with a first temporal layer index of the video;
• wherein a first coding tool is applicable to a first video block of the first video data unit, wherein the first coding tool comprises, based on a first side information related to the first coding tool, processing the first video block based on a filtering process using adaptive loop filter coefficients, and
• wherein the first side information is determined based on one or more first adaptation parameter sets for the first coding tool, and wherein the one or more first adaptation parameter sets are associated with a second temporal layer index which is less than or equal to the first temporal layer index.