Optimization And Implementation Of The H.264 Encoder Based On Equator's BSP-16

The newest standard approved by the ITU-T and ISO/IEC organizations is H.264/AVC, it represents a number of advances in video coding technology and becomes the newest international video coding standard because of both high coding efficiency and network friendliness. But the experiment results show that the improved coding efficiency comes with great complexity increase at the encoder. In fact, proper use of the H.264/AVC encode methods lead to roughly the same performances as the complex configuration. So both computational complexity and coding efficiency should be thought and made to the optimal trade-off in the implementation of actual coding system.In this paper, we present the design of H.264 encoder, based on the open source codec X264 ( one of the most successful H.264 encoders on the PC platform ) and BSP-16 development platform -- Babelfish II development board and iMMediaTools SDT. In order to reduce the complexity of the encoder, the fast algorithms are developed to replace the old one and the multimedia instruction set are used to optimize the basic modules. This dissertation is based on the above methods, and major works are as follows.Because in the X264, the full search algorithm is used to choose the best intra prediction mode. However it is very computationally expensive. To reduce the complexity of the intra prediction of the encoder, one fast intra-prediction mode selection algorithm for luma 16*16 block and one for luma 4*4 block are proposed. The fast algorithm for luma 16*16 block is using the macroblock properties to fast determine the best mode. And the algorithm for luma 4*4 block is using the modes with similar neighborhood direction have similar costs to fast determine.To further optimize the performance of the encoder, the multimedia intruction set of BSP-16 is used. Based on the analyse of the encoder, the relatively time-consuming modules such as motion estimate, motion compensation, integer transform, quantization and sub-pel interpolation are optimized through the FIRtree multimedia instruction set of BSP-16, which further improve the encoding rate.The experiment results show that after optimizing H.264 encoder at algorithm and instruction level, the computationally intensive modules in H.264 encoder was further optimized, and the encoder was significantly speeded up. And finally the optimized encoder can realize the real-time encoding (for CIF sequences) on the Babelfish II platform.