Research On Implementation And Optimization Of H.264Encoder Based On ARM Platform

As the most popular video encode standard in the modern world,H.264/AVC has lots of strengths including high compression ratio and PSNR(peak signal-to-noise ratio) values, good subjective evaluation and etc.Though H.264/AVC has these advantages, the standard also greatly increasesthe computational complexity of the encoder because of having introducedsome advanced techniques to this standard. So it is impossible to run real timeH.264sequence encoder and decoder in an embedded system which not haveenough resource and calculate ability. This issue made the application ofH.264on the embedded system got restricted. Having the advantage of fastencoding speed and high output quality, X264has become the most successfulopen source H.264/AVC encoder. But the experiment has show that evenX264cannot encode the QCIF sequence in time on embedded platform. Afterresearch H.264/AVC standard and basic theory of each module in encodeprocess in detail, analysis the origin code of X264encoder, we succeed intransplant X264software to the ARM platform. Then we improved theefficiency of X264through C code level and assembler level optimization, and promote the fps (Frames Per Second) by80%.This paper also concentrates on research the method to decrease thecalculation complexity of intra prediction module in H.264encoder process.Base on the features of intra prediction algorithm, this paper presented a fastalgorithm for intra4×4block prediction, using the relation between (Sum ofAbsolute Hadamard-Transformed Difference) algorithm and RDO tech aswell as other optimization methods. Experimental result shown that thealgorithm have reduced40%time consumption in encoding H.264sequencegreatly, without losing video quality obviously.