Interframe Block-matching Algorithm Of H.264 Encoder Dsp Realization

ITU-T Video Coding Experts Group and the ISO/IEC Moving Picture Experts Group work together to work out a new video coding standard—H.264.This new standard can save approximately a 50% bit rate for equivalent perceptual quality relative to the existing standards,because of introducing the new techniques of intra prediction,inter prediction and so on.Due to the advanced compression performance and the "network-friendly"nature,H.264 will be adopted over a broad variety of applications such as video telephone,broadcast,streaming services,storage and so on.H.264 encoder achieves better performances at the cost of a larger computing consumption.The paper will emphasis on research of Motion Estimation and Motion Compensation algorithm and the implementation of H.264 video encoder based on DM642 platform.A fast decision algorithm is proposed based on relativity of motion vector in order to effectively decrease the complexity in inter-mode decision of H.264, which referes to the high relativity among the four sub-macroblock of current encoded macroblock. This algorithm determines whether to unite sub-macroblock or macroblock according to the relativity of motion vector of sub-macroblock to avoid to ransack the seven prediction modes. The Simulation demonstrates that the proposed algorithm can reduce the computation complexity with high Image quality and low bit rate simultaneously.On the basis of analysis on the coding flow of H.264, the transplant of the H.264 baseline profile encoder from PC to DSP was fulfilled firstly. Then several implementation techniques for optimization were presented based on the characteristics of DM642 chip. The H.264 Baseline Profile encoder is finally real-time implemented based on DM642 platform. The testing results demonstrate that encoder has sped up remarkably after optimization.