Geometric partition mode with motion vector refinement

An apparatus for video coding, comprising:

• one or more processors;
• and
• a non-transitory computer-readable storage medium configured to store instructions executable by the one or more processors;
• wherein the one or more processors, upon execution of the instructions, are configured to:
• partition a video block into first and second geometric partitions;
• receive a first GPM with a motion vector refinement (GPM-MVR) enable flag for the first geometric partition and receiving a second GPM-MVR enable flag for the second geometric partition, wherein in response to determining the first GPM-MVR enable flag or the second GPM-MVR enable flag equals to 1, receiving syntaxes indicating a magnitude and a direction of a MVR;
• receive a joint template matching (TM) enable flag for the first and second geometric partition, wherein the joint TM enable flag jointly indicates whether a uni-directional motion of the first partition is refined by TM and whether a uni-directional motion of the second partition is refined by the TM;
• receive a first merge GPM index for the first geometric partition and a second merge GPM index for the second geometric partition;
• construct a uni-directional motion victor (MV) candidate list of the GPM;
• generate a uni-directional MV for the first geometric partition and a uni-directional MV for the second geometric partition, based on the first GPM-MVR enable flag, the second GPM-MVR enable flag, the joint TM enable flag, the first merge GPM index and the second merge GPM index;
• and
• constrain the first merge GPM index and the second merge GPM index based on the joint TM enable flag, including, in response to determining that one of the first and second GPM-MVR enable flags is 0 and the other of the first and second GPM-MVR enable flags is 1, determining that the first merge GPM index and the second merge GPM index are allowed to be identical.

A computer readable storage medium storing a bitstream formed by instructions which when executed by a computing device having one or more processors, cause the one or more processors to perform steps comprising:

• partitioning a video block into first and second geometric partitions;
• receiving a first GPM with a motion vector refinement (GPM-MVR) enable flag for the first geometric partition and receiving a second GPM-MVR enable flag for the second geometric partition, wherein in response to determining the first GPM-MVR enable flag or the second GPM-MVR enable flag equals to 1, receiving syntaxes indicating a magnitude and a direction of a MVR;
• receiving a joint template matching (TM) enable flag for the first and second geometric partition, wherein the joint TM enable flag jointly indicates whether a uni-directional motion of the first partition is refined by TM and whether a uni-directional motion of the second partition is refined by the TM;
• receiving a first merge GPM index for the first geometric partition and a second merge GPM index for the second geometric partition;
• constructing a uni-directional motion victor (MV) candidate list of the GPM;
• generating a uni-directional MV for the first geometric partition and a uni-directional MV for the second geometric partition, based on the first GPM-MVR enable flag, the second GPM-MVR enable flag, the joint TM enable flag, the first merge GPM index and the second merge GPM index;
• and
• constraining the first merge GPM index and the second merge GPM index based on the joint TM enable flag, including, in response to determining that one of the first and second GPM-MVR enable flags is 0 and the other of the first and second GPM-MVR enable flags is 1, determining that the first merge GPM index and the second merge GPM index are allowed to be identical.