Systems and methods for performing inter prediction in video coding

A method of coding video data, the method comprising:

• coding a merge subblock flag that specifies whether subblock-based inter prediction parameters for a coding unit are inferred from neighboring blocks and that determines whether a motion vector difference merge flag and a combination flag are to be coded;
• determining a value of the merge subblock flag;
• coding the motion vector difference merge flag after the value of the merge subblock flag is determined as being equal to zero and a value of a motion vector difference flag is determined as being equal to one;
• and
• coding the combination flag that specifies whether a combined inter-picture merge and intra-picture prediction is applied for the coding unit by using the merge subblock flag and a sequence parameter set (SPS) flag for the combined inter-picture merge and intra-picture prediction,
• wherein:
• the motion vector difference merge flag specifies that a prediction parameter with a motion vector difference is used, and
• the motion vector difference flag specifies whether a merge mode with motion vector difference (MMVD) mode is enabled.

A device comprising:

• one or more processors;
• and
• a storage device coupled to the one or more processors and storing computer-executable instructions which, when executed by at least one of the one or more processors, cause the device to:
• decode a merge subblock flag that specifies whether subblock-based inter prediction parameters for a coding unit are inferred from neighboring blocks and that determines whether a motion vector difference merge flag and a combination flag are to be decoded;
• determine a value of the merge subblock flag;
• decode the motion vector difference merge flag after the value of the merge subblock flag is determined as being equal to zero and a value of a motion vector difference flag is determined as being equal to one;
• and
• decode the combination flag that specifies whether a combined inter-picture merge and intra-picture prediction is applied for the coding unit by using the merge subblock flag and a sequence parameter set (SPS) flag for the combined inter-picture merge and intra-picture prediction,
• wherein:
• the motion vector difference merge flag specifies that a prediction parameter with a motion vector difference is used, and
• the motion vector difference flag specifies whether a merge mode with motion vector difference (MMVD) mode is enabled.