Content adaptive motion compensation filtering for high efficiency video coding

摘要

A system and method for adaptive motion filtering to improve subpel motion prediction efficiency of interframe motion compensated video coding is described. The technique uses a codebook approach that is efficient in search complexity to look-up best motion filter set from a pre-calculated codebook of motion filter coefficient set. In some embodiments, the search complexity is further reduced by partitioning the complete codebook into a small base codebook and a larger virtual codebook, such that the main calculations for search only need to be performed on the base codebook.

主权项

1. A video-encoder-device-implemented method for encoding an adaptive motion-compensation filter set for a plurality of subpel positions for predicting portions of an encoded video frame, the method comprising:
obtaining, by the video encoder device, a codebook comprising a multiplicity of motion-compensation filters grouped into a plurality of subpel-position groups that respectively correspond to the plurality of subpel positions, each of the plurality of subpel-position groups comprising a plurality of motion-compensation filters suitable for interpolating portions of a picture at a corresponding one of the plurality of subpel positions, the plurality of motion-compensation filters comprising a base codebook of filter sets and a virtual codebook of filter sets, the virtual codebook of filter sets comprising combinations of filters selected from the base codebook of filter sets; obtaining, by the video encoder device, an unencoded frame of video for encoding by the video encoder device; selecting a portion of the frame of video as a picture partition according to a partitioning mode; encoding, by the video encoder device, the selected picture partition to a bitstream; and during encoding of the picture partition, the video encoder device:
selecting from the codebook a subset of the plurality of motion-compensation filters as being well-adapted for predicting the picture partition, the selected subset comprising one from each of the plurality of subpel-position groups; andincluding in the bitstream a code identifying the picture partitioning mode and a subpel-filter code identifying the selected subset of the plurality of motion-compensation filters within the codebook.