Transform domain temporal prediction with extended blocks
Traditional temporal prediction relies on motion compensated pixel copying operations. Such per-pixel temporal prediction was shown in prior work to be sub-optimal since it ignores the underlying spatial correlation. Transform domain temporal prediction (TDTP) was thus proposed previously to first achieve spatial decorrelation within the block using DCT, then apply an optimal one-to-one prediction per frequency. However, for sub-pixel motion compensation, the low-pass filter used for interpolation interferes with TDTP. In this paper, we propose an extended block based TDTP, which: i) completely disentangles spatial and temporal correlations to fully account for the sub-pixel interpolation effect, and ii) fully exploits spatial correlations around reference block boundary. Experimental evidence is provided for substantial coding gains over standard HEVC.