基于Trimedia DSP的H.264解码算法优化

H.264是最新的视频编码标准,具有非常优良的编码性能,但它的算法复杂度也很高,很难满足实时应用的需要。论文详细分析了影响H.264解码速度的因素,提出了基于TrimediaDSP平台的优化方案。该方案通过缩减不必要的判断、避免频繁的内存访问、优化内存的分配与使用、合理使用循环展开以及采用DSP专用指令等方法来提高H.264解码算法的运算速度。测试结果表明:优化后的代码运行速度平均提高了8倍,在主频为200MHz的TrimediaDSP上能实时解码CIF格式的H.264基本码流。

H.264 Decoder Optimization for Trimedia DSP

H.264 is the latest video coding standard with high coding performance.But its computational complexity is also too high to be used in real time environment.In this paper,key factors,which have great influence to the decoding speed,have been examined.Then an optimization solution designed for Trimedia DSP platform is presented to speed up decoding of H.264.Many techniques are covered in this solution,including:reducing redundant flow control,minimizing memory access,taking care of the allocation and usage of memory,properly performing loop unrolling and utilizing DSP-specific instructions to improve Instruction Level Parallelism(ILP).Simulation results show this solution can accelerate the decoding speed by an average factor of about 8 times.Experimental result on Trimedia DSP with an operation frequency of 200MHz demonstrates that optimized code can decode CIF-format H.264 stream in real time.