Optimization And Implementation Of H.264 Encoding Algorithm Based On Davinci Platform

H.264 standard has become a new generation of international video encoding standard for its high encoding efficiency and good network compatibility, which has a very broad application prospect in the area of digital media. H.264 encoding algorithm has high encoding quality but also high complexity, while the DSP chip is especially suitable for dealing with complex digital signal processing algorithms such as video encoding with its high processing speed and low consumption of resource through dedicated instructions and architectural design. Davinci platform launched by TI which combines the C64x+ DSP with ARM9 processor has presently become an ideal platform of H.264 encoding algorithm's implementation and application for its high calculating performance and rich peripheral interfaces.This paper focuses on the research of H.264 encoding algorithm and optimization and implementation of H.264 encoding algorithm based on davinci platform (TMS320DM6467).The research of H.264 encoding algorithm:The H.264 encoding algorithm's principle and core technology are analyzed in detail and the bottleneck modules which impact on the speed of H.264 encoding are identified. In the intra prediction mode decision module, standard mode decision algorithm is analyzed. Then an improved intra prediction mode decision algorithm is proposed, which improves the speed of intra prediction effectively by using the correlation of prediction model, changing the order of prediction mode decision and stoping the prediction model selection ahead of time. In the inter prediction motion estimation algorithm module, the classical block-matching algorithms and the UMHexagonS, EPZS algorithm are analyzed, then an algorithm which combines the Diamond and T-Shaped searching is proposed through the feature that natural image sequences'best matching block always shows obvious directional property (gradient direction). The next search template and direction are decided according to the relative position of the current and previous search starting point. The improved algorithm obtains a nice balance between the algorithm complexity and encoding performance and achieves a good operating result.Optimization and implementation of the algorithm based on davinci platform:The davinci platform and DM6467 chip's feature and the realization process of the H.264 encoding algorithm on davinci platform are introduced in detail. H.264 encoding algorithm which was under the PC environment is modifyed to be DSP-based and the interfaces are packaged. The efficiency of H.264 encoding algorithm is improved substantially by taking full advantage of DM6467 hardware and optimizating the algorithm's implementation through the compiler options, configuration of memory and C and assembly code.Finally, the H.264 encoding algorithm implemented on DM6467 platform whose CIF format video sequence average encoding rate has been upgraded to 1.8.11 fps from 2.63 fps before optimization, achieves the real-time requirement basically.The size of the encoded stream is about 2.33% of the input stream and the decoded video image has a high quality.