H.264 Standard Search Algorithm

The new video coding standard H.264, jointly made by ITU-T Video Coding Experts Group (VCEG) and ISO/IEC MPEG video group, has gained more and more attention, mainly due to its high coding efficiency and minor increase in decoding complexity.Compared to H.263 or MPEG-4, up to 50% of bit-rate reduction can be achieved with H.264. It can provide both objective and subjective image quality superior to existing standards.Some new techniques, such as intra-frame prediction, inter-frame prediction ,IP/IS frame, adaptive block size motion compensation with small block sizes, Quarter-pel accurate motion compensation, integer transformation, synchronizations witching pictures, multiples reference pictures ,context-adaptive variable length coding (CAVLC),context-adaptive binary arithmetic coding (CABAL) and in-loop deblocking filter are used in this standard.With the use of these techniques, both compression efficiency and encoding quality are greatly improved. The testing results show that H.264 can greatly outperform existing video coding standards in PSNR, visual quality and compression efficiency.However, most of the coding tools adopted in H.264 involve very large computation complexity. Therefore the complexity of the encoder and computational cost are increased at the same time. That makes it very difficult for practical applications such as in real time video communication application or in some embedded system.To reduce the complexity of H.264, a number of efforts have been made to explore the fast algorithms in motion estimation, intra mode prediction and inter mode prediction for H.264 video coding standard.To overcome this defect, many fast Block Matching Algorithm (BMAs) are developed such as Full Search (FS), 2D Logarithmic (TDL), Three Step Search (TSS), Cross Search (CS), Diamond Search (DS), etc.By studing the classical motion search algorithms, giving their advantage & disadvantage, this paper presents a new algorithm. Experiment shows that the new algorithm can not only contain the PSNR, but improve the search-effiency. It also achieves the paper's anticipatory result, and is goos for video picture real-time process.