Research On The Interpolation Based On H.264 Standard

With the development of the techniques in storage, communication, processor and the increase of high quality video service requirement, a lot of new techniques are proposed in video coding field, such as intra prediction, variable block size motion compensation, quarter sample accurate motion estimation, 4×4 block size transform and so on. H.264 which adopts these techniques is the newest international video coding standard.Extrapolation technique of intra prediction in H.264 is used to generate the prediction block from previously encoded and reconstructed blocks of current frame. This technique is based on directional spatial texture concept. Analysis of this technique revealed two problems: First, known information has not been fully utilized, when all the reference pixels are available, only 30%~60% can be used; Second, gradational property of spatial texture hasn't been taken into account, simply replicate operation is premised on that all the pixels don't change in the same directional spatial texture. A new extrapolation technique of intra prediction is proposed to predict the gradational trend in the same directional spatial texture by utilizing the rest available information. Experiment results show that proposed extrapolation technique of intra prediction has better rate distortion performance with slightly computation complexity increasing.Interpolation technique of inter prediction in H.264 is used in quarter sample accurate motion estimation to generate the fractional pixels by applying FIR filter horizontal and vertical. Analysis revealed that this technique lead to the computation and memory access bottleneck. A new 4 tap FIR filter [-3, 19, 19, -3]/32 is designed and a new interpolation technique is accordingly proposed. Complexity analysis and experiment results show that compared with interpolation technique in H.264, 10% memory access and 18.2% computation complexity are reduced by the proposed technique with slightly rate distortion performance degrading. Proposed technique is more suitable for implementing real time video codec on VLSI, DSP chips.