Method and apparatus for video coding

An apparatus of video decoding, comprising:

• processing circuitry configured to:
• receive and decode a split direction syntax element, a first index syntax element, and a second index syntax element that are associated with a coding block of a picture,
• the coding block being coded according to a triangular prediction mode and partitioned into a first prediction unit and a second prediction unit according to a split direction,
• the first index syntax element being coded according to first one or more bins, and
• the second index syntax element being coded according to second one or more bins;
• derive a triangular prediction index for the coding block based on a first value indicated by the first index syntax element, a second value indicated by the second index syntax element, and a third value indicated by the split direction syntax element, wherein the split direction syntax element, the first index syntax element, and the second index syntax element are transmitted in a bitstream in the order of the split direction syntax element followed by the first index syntax element followed by the second index syntax element;
• determine the split direction by processing the triangular prediction index;
• determine a first merge index by processing the triangular prediction index, the first merge index identifying first motion information in a merge candidate list constructed for the coding block;
• determine a second merge index by processing the triangular prediction index, the second merge index identifying second motion information in the merge candidate list constructed for the coding block;
• determine first prediction samples of the first prediction unit according to the first motion information;
• determine second prediction samples of the second prediction unit according to the second motion information;
• and
• reconstruct the coding block according to the first prediction samples of the first prediction unit and the second prediction samples of the second prediction unit.

A non-transitory computer-readable medium storing instructions which, when executed by a computer for video decoding, cause the computer to perform a method of video decoding, the method comprising:

• receiving and decoding a split direction syntax element, a first index syntax element, and a second index syntax element that are associated with a coding block of a picture,
• the coding block being coded according to a triangular prediction mode and partitioned into a first prediction unit and a second prediction unit according to a split direction,
• the first index syntax element being coded according to first one or more bins, and
• the second index syntax element being coded according to second one or more bins;
• deriving a triangular prediction index for the coding block based on a first value indicated by the first index syntax element, a second value indicated by the second index syntax element, and a third value indicated by the split direction syntax element, wherein the split direction syntax element, the first index syntax element, and the second index syntax element are transmitted in a bitstream in the order of the split direction syntax element followed by the first index syntax element followed by the second index syntax element;
• determining the split direction by processing the triangular prediction index;
• determining a first merge index by processing the triangular prediction index, the first merge index identifying first motion information in a merge candidate list constructed for the coding block;
• determining a second merge index by processing the triangular prediction index, the second merge index identifying second motion information in the merge candidate list constructed for the coding block;
• determining first prediction samples of the first prediction unit according to the first motion information;
• determining second prediction samples of the second prediction unit according to the second motion information;
• and
• reconstructing the coding block according to the first prediction samples of the first prediction unit and the second prediction samples of the second prediction unit.