Signaling of cu based interpolation filter selection

An apparatus for video decoding, comprising processing circuitry configured to:

• decode prediction information for a current block in a current picture that is a part of a coded video sequence, the prediction information indicating a fractional motion vector for the current block;
• select one of an integer motion vector, a first interpolation filter, or a second interpolation filter for the current block including
• before a memory bandwidth usage in a pixel area that is being decoded reaches a target bandwidth, select the second interpolation filter having a number of taps independent of block size, and
• after the memory bandwidth usage reaches the target bandwidth and the pixel area is still being decoded, select one of (i) the first interpolation filter having a number of taps dependent on the block size or (ii) the integer motion vector;
• and
• reconstruct the current block based on the selected one of the integer motion vector, the first interpolation filter, or the second interpolation filter.

A non-transitory computer-readable storage medium storing a program executable by at least one processor to perform:

• decoding prediction information for a current block in a current picture that is a part of a coded video sequence, the prediction information indicating a fractional motion vector for the current block;
• selecting one of an integer motion vector, a first interpolation filter, or a second interpolation filter for the current block including
• before a memory bandwidth usage in a pixel area that is being decoded reaches a target bandwidth, selecting the second interpolation filter having a number of taps independent of block size, and
• after the memory bandwidth usage reaches the target bandwidth and the pixel area is still being decoded, selecting one of (i) the first interpolation filter having a number of taps dependent on the block size or (ii) the integer motion vector;
• and
• reconstructing the current block based on the selected one of the integer motion vector, the first interpolation filter, and the second interpolation filter.