Weight derivation for geometric partitioning mode

A method of video decoding at a video decoder, comprising:

• receiving a bitstream of a coded video associated with a current coding block that is partitioned into a first part and a second part along a partition edge for prediction in a geometric partitioning mode;
• determining a weight index at a sample position of the current coding block based on a look up table, the weight index being used to derive a blending weight for blending two prediction signals corresponding to the first part and the second part of the current coding block;
• determining a stored motion vector type for a first motion storage unit in a motion field of the current coding block based on a motion index of the first motion storage unit, the first motion storage unit having a size of 4×4 samples, the motion index of the first motion storage unit being equal to sum of a first value multiplied by a first value of the look up table and a second value multiplied by a second value of the look up table;
• and
• storing a motion vector of the first motion storage unit based on the stored motion vector type determined for the first motion storage unit of the current coding block.

A method of video encoding at a video encoder, comprising:

• determining a weight index at a sample position of a current coding block based on a look up table, the current coding block being partitioned into a first part and a second part along a partition edge for prediction in a geometric partitioning mode, the weight index being used to derive a blending weight for blending two prediction signals corresponding to the first part and the second part of the current coding block;
• determining a stored motion vector type for a first motion storage unit in a motion field of the current coding block based on a motion index of the first motion storage unit, the first motion storage unit having a size of 4×4 samples, the motion index of the first motion storage unit being equal to sum of a first value multiplied by a first value of a look up table and a second value multiplied by a second value of the look up table;
• and
• storing a motion vector of the first motion storage unit based on the stored motion vector type determined for the first motion storage unit of the current coding block.

A method of processing visual media data, the method comprising:

• performing a conversion between a visual media file and a bitstream of visual media data according to a format rule, wherein
• the bitstream includes at least one syntax element that indicates a current coding block is partitioned into a first part and a second part along a partition edge for prediction in a geometric partitioning mode;
• and
• the format rule specifies that
• a weight index at a sample position of the current coding block is determined based on a look up table in the geometric partitioning mode, the weight index being used to derive a blending weight for blending two prediction signals corresponding to the first part and the second part of the current coding block,
• a stored motion vector type for a first motion storage unit in a motion field of the current coding block is determined based on a motion index of the first motion storage unit, the first motion storage unit having a size of 4×4 samples, the motion index of the first motion storage unit being equal to sum of a first value multiplied by a first value of a look up table and a second value multiplied by a second value of the look up table, and
• a motion vector of the first motion storage unit is stored based on the stored motion vector type determined for the first motion storage unit of the current coding block.