H.264 Rate Control Algorithm Based On DSP

With the development of the network information, the processing and transmission technology of video information and multimedia information become the current hot spots. As the latest generation of video compression standards, H.264, with its high compression ratio and excellent image compression quality, has been widely accepted. Video encoding has a very broad application prospect, while the rate control algorithm in encoding plays a decisive role, and for different applications, its control strategy has strong flexibility.This paper describes the principle standard, characteristics, and the key technologies of implementation of H.264 encodeing standard, on this basis, comparatively analysis the advantages and disadvantages of the classical rate control algorithm used in the international encoding standards.Then analysis the rate control algorithm JVT-G012 used in the H.264 standard detailedly, describe the working principle, characteristics, work processes and implementation methods of the JVT-G012, verify the importance of rate control and initial quantitative parameters on the impact of rate control through the Simulation results. At the same time, find that in the basic unit layer rate control of JVT-G012, the most simple linear model is using in the complexity estimate, and do not take full advantage of space-time correlation in the encoded frame, to rectify this shortcoming, this article uses the new model to implement the complexity estimates,in the new model, The MAD value of the basic unit layer in the current encoded frame will be introduced into the original MAD model. This improvement can be a good use of space-time correlation of the encoded frame, so that the complexity estimates is more accurate. Then, embed the new model into the test model JM8.6 through the programing and verify the feasibility of the improving in the slow movement, fast movement and scene change scenarios, etc in Baseline Profile of JM8.6. The experimental results show that the improved model is more accurate, make the video image quality better, decrease the time of encoding, and the improved model has a good performance.This paper makes a DSP migration and optimization of the model JM8.6 which has been embedded by the improving model according to the characteristics of the TI TMS320DM642 platform. In the migration stage, by removing redundant code, and modifying the data types, libraries and header files, as well as setting the compiler options to enable JM8.6 compiled and run in CCS. In order to achieve a better rate control effect, hardware-level optimization is necessary. In the optimization stage, through the inline functions, software pipelining, linear compilation and storage space allocation, the performance of the new model has been further improved. Experimental datas show that the new model can achieve a better rate control effect in the hardware platform for H.264, the decoded image clearer, encoding time shorter, and real-time efficient.