Motion compensation using decoder-defined vector quantized interpolation filters

Abstract

The present disclosure describes use of dynamically assignable interpolation filters as part of motion compensated prediction. An encoder and a decoder each may store common codebooks that define a variety of interpolation filters that may be applied to predicted video data. During runtime coding, an encoder calculates characteristics of an ideal interpolation filter to be applied to a reference block that would minimize prediction error when the reference block would be used to predict an input block of video data. Once the characteristics of the ideal filter are identified, the encoder may search its local codebook to find a filter that best matches the ideal filter. The encoder may filter the reference block by the best matching filter stored in the codebook as it codes the input block. The encoder also may transmit an identifier of the best matching filter to a decoder, which will use the interpolation filter on predicted block as it decodes coded data for the block. The encoder and decoder may build their codebooks and maintain them independently from the other but in synchronism. The encoder and decoder may use decoded pixel block data as source data for calculation of interpolation filters.