Chroma motion vector processing apparatus, system, and method

A computer-implemented method, comprising:

• retrieving from a compressed video stream a current slice of a picture encoded in the compressed video stream;
• retrieving from the compressed video stream first and second reference lists for the current slice;
• setting, by a processor circuit, a chroma motion vector for a current block of the current slice equal to a luma motion vector for the current block;
• determining whether the current block is a field block;
• when the current block is a field block, adjusting the chroma motion vector based on one or more pre-computed chroma motion vector adjustment arrays for the current slice, the pre-computed chroma motion vector adjustment arrays pre-computed based on the first reference list and the second reference list, the current slice comprising multiple macroblocks and one of the multiple macroblocks comprising the current block;
• determining whether the current slice is a macroblock adaptive frame field (MBAFF) slice when the current block is a field block;
• determining whether the current block is a top block or a bottom block when the current slice is an MBAFF slice and the current block is a field block;
• and
• adjusting the chroma motion vector based on top parameters comprised in a first pre-computed chroma adjustment array for the first reference list for the current slice and on top parameters comprised in a first pre-computed chroma adjustment array for the second reference list for the current slice when the current slice is an MBAFF slice and the current block is a top block.

At least one non-transitory machine-readable medium comprising a set of instructions that, in response to being executed on a computing device, cause the computing device to:

• retrieve from a compressed video stream a current slice of a picture encoded in the compressed video stream;
• copy a luma motion vector for a current block of the current slice to a chroma motion vector for the current block;
• determine whether the current block is a field block;
• when the current block is a field block, adjust the chroma motion vector based on multiple pre-computed chroma motion vector adjustment arrays for the current slice, the current slice comprising multiple macroblocks and one of the multiple macroblocks comprising the current block
• determine whether the current slice is a macroblock adaptive frame field (MBAFF) slice when the current block is a field block;
• determine whether the current block is a top block or a bottom block when the current slice is an MBAFF slice and the current block is a field block;
• and
• adjust the chroma motion vector based on top parameters comprised in a first pre-computed chroma adjustment array for a first reference list for the current slice and on top parameters comprised in a first pre-computed chroma adjustment array for a second reference list for the current slice when the current slice is an MBAFF slice and the current block is a top block.