Interaction between merge list construction and other tools

An apparatus for coding 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:

• determine, based on a first threshold (T1), a maximum number of history-based motion vector prediction (HMVP) candidates in an HMVP table to be checked, wherein the HMVP table includes one or more HMVP candidates, and wherein the one or more checked HMVP candidates in the HMVP table are used for constructing a motion candidates list;
• make a decision regarding a selective checking of a number of the HMVP candidates in the HMVP table in an order, the number of the HMVP candidates in the HMVP table checked not exceeding the maximum number of HMVP candidates to be checked;
• construct, based on the decision, the motion candidates list;
• and
• perform, based on the motion candidates list, a conversion between a current block of a video and a bitstream of the video,
• wherein checking the HMVP candidates in the HMVP table is terminated upon a determination that a number of available motion candidates in the motion candidates list, including added HMVP candidates, has reached a maximally allowed number of motion candidates in the motion candidates list minus a second threshold (T2), and wherein T2 is based on a coding mode of the current block.

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

• determine, based on a first threshold (T1), a maximum number of history-based motion vector prediction (HMVP) candidates in an HMVP table to be checked, wherein the HMVP table includes one or more HMVP candidates, and wherein the one or more checked HMVP candidates in the HMVP table are used for constructing a motion candidates list;
• make a decision regarding a selective checking of a number of the HMVP candidates in the HMVP table in an order, the number of the HMVP candidates in the HMVP table checked not exceeding the maximum number of HMVP candidates to be checked;
• construct, based on the decision, the motion candidates list;
• and
• perform, based on the motion candidates list, a conversion between a current block of a video and a bitstream of the video,
• wherein checking the HMVP candidates in the HMVP table is terminated upon a determination that a number of available motion candidates in the motion candidates list, including added HMVP candidates, has reached a maximally allowed number of motion candidates in the motion candidates list minus a second threshold (T2), and wherein T2 is based on a coding mode of the current block.

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:

• determining, based on a first threshold (T1), a maximum number of history-based motion vector prediction (HMVP) candidates in an HMVP table to be checked, wherein the HMVP table includes one or more HMVP candidates, and wherein the one or more checked HMVP candidates in the HMVP table are used for constructing a motion candidates list;
• making a decision regarding a selective checking of a number of the HMVP candidates in the HMVP table in an order, the number of the HMVP candidates in the HMVP table checked not exceeding the maximum number of HMVP candidates to be checked;
• constructing, based on the decision, the motion candidates list;
• and
• generating the bitstream based on the motion candidates list,
• wherein checking the HMVP candidates in the HMVP table is terminated upon a determination that a number of available motion candidates in the motion candidates list, including added HMVP candidates, has reached a maximally allowed number of motion candidates in the motion candidates list minus a second threshold (T2), and wherein T2 is based on a coding mode of the current block.