Optimization Of RealVideo Decoding Based On SIMD Technology For Loongson

RealVideo player is one of the most important applications for Loongson-2 processor. As the current mainstream network video format, RealVideo increases performance while it also brings a series of more complicated coding/decoding algorithms, which put pressure on RealVideo files playing on the Loongson-2 platform with lower frequency.On the Loongson-2 platform, with no multi-media optimization the time of RealVideo decoding accounts for more than 90% of the total playing time, in which the core application functions, such as deblocking filter, motion compensation interpolation operation, reconstruction, and dequantify, consume about 60% of the total decoding time. In order to enhance the ability of multimedia processing of Loongson-2 CPU, a set of 64-bit fix-point SIMD multimedia instruction has been designed and implemented, which make it possible to optimize RealVideo decoding on Loongson platform.Based on the technology of SIMD on the Loongson-2 platform, this paper made the multimedia optimization for RealVideo codecs. First, the core compression algorithm of the RealVideo was lucubrated in the perspective of static program analysis and the preliminary optimization direction came out. Second, the dynamic performance analysis on the Loongson-2 platform was made from executition time and dynamic instructions. And the results of the two aspects analysis coincide with that of the static analysis, suth that the core of the codec decoding function was identified. Finally, by analyzing data parallelism of these core functions and the character of the Loongson-2 system, the RealVideo codecs based on multimedia instruction was optimized.The efficiency of RealVideo codecs after optimization on the Loongson-2 platform has been enhanced by 30%, and that of the RealVideo playing has been improved by 20%. Based on the Loongson SIMD technology, this method of optimization of RealVideo codec has made fairly satisfactory results.