A wavelet-based video coding scheme using image warping prediction
This paper describes a video coding algorithm that combines new ideas in motion estimation and wavelet-based coding techniques. A motion estimation technique using an image warping model is employed to reduce temporal redundancies in a given image sequence. The underlying continuous motion model is based on a bilinear warp of a grid of quadrangles. It has the advantage of dealing with more complex motion than simple block matching schemes. In addition, a block adaptive high-quality texture interpolation is used to further improve the quality of the prediction. The prediction error image is decorrelated using a wavelet transform coupled with a framework of highly efficient pre-coding techniques utilizing the concepts of partitioning, aggregation and conditional coding (PACC). This combined coding strategy has proved to be very efficient both with respect to subjective and objective measures. The improvements achieved with our proposed coder compared to the H.263 coder (with all options applied) range from 0.5 to 1.2 dB PSNR. Especially at very low bit-rates where reconstructed videos of block-based coders suffer from visually annoying blocking artifacts the proposed coding scheme produces a superior subjective quality.