Fast Encoding Algorithms for Video Coding with Adaptive Interpolation Filters

In order to compensate for the temporally changing effect of aliasing and improve the coding efficiency of video coders, adaptive interpolation filtering schemes have been recently proposed. In such schemes, encoder computes the interpolation filter coefficients for each frame and then reencodes the frame with the new adaptive filter. However, the coding efficiency benefit comes with the expense of increased encoding complexity due to this additional encoding pass. In this paper, we present two novel algorithms to reduce the encoding complexity of adaptive interpolation filtering schemes. First algorithm reduces the complexity of the second encoding pass by using a very lightweight motion estimation algorithm that reuses the data already computed in the first encoding pass. Second algorithm eliminates the second coding pass and re-uses the filter coefficients already computed for previous frames. Experimental results show that the proposed methods achieve between 1.5 to 2 times encoding complexity reduction with practically negligible penalty on coding efficiency.