A study on a fast intra prediction scheme with intra prediction skip and early termination of intra prediction mode decision in H.264|MPEG-4 part 10 advanced video coding

Abstract

H.264|MPEG-4 Part 10 Advanced Video Coding (AVC) is a recently standardized video coding standard jointly developed by ITU-T SG16 Q.6 and ISO/IEC JTC1 SC29 WG11 (MPEG: Moving Picture Expert Group). The AVC has greatly improved coding efficiency compared to its preceding video coding standards such as MPEG-1/2 Video, MPEG-4 Part 2 Visual, H.261 and H.263 etc. The AVC adopts several coding tools to enhance the coding efficiency at the expense of large computational complexity, one of which is intra prediction in spatial domain. The intra prediction in AVC incorporates directional spatial prediction for 4$\times$4, 8$\times$8, and 16$\times$16 blocks in each macroblock (MB) to be coded. Especially, the 4$\times$4 and 8$\times$8 blocks in an MB have rate-distortion optimization (RDO) based 9 directional prediction modes while 16$\times$16 blocks have 4 modes. For intra prediction, the Baseline profile of AVC with 4$\times$4 and 16$\times$16 intra prediction requires 592 times the computation of RDO based costs to search the best spatial prediction mode for each MB, and the High profile of AVC with additional 8$\times$8 intra prediction requires 736 times for it. This makes it difficult the AVC software encoders for real-time applications due to large amounts of computation required for the intra prediction. Moreover the intra prediction tool is not only used for I-Slices, but also for P- and B-Slices, which further increases computational complexity. In this thesis, we propose a fast intra prediction scheme with 4$\times$4 intra prediction skip and early termination of intra mode decision for AVC: (1) The proposed intra prediction skipping method is to decide whether or not to perform the intra prediction in P- and B-Slices for which the decision on intra prediction skip is made based on motion information of the current block and the probabilities of the most probable modes of intra prediction in its neighboring blocks; (2) the proposed fast intra mode decis...