| The new generation video coding standard AVS+(Audio and Video codingStandard Plus), which was proposed by "Digital Audio Video Coding StandardWorking Group", is aimed to fulfill the future demand of3D and high definitiondigital TV. Compared with the original AVS standard, AVS+promotes the codingefficiency greatly, it increases the complexity nevertheless. With the development ofmulti-core processor and the progress of parallel program design, parallel videocoding has become an efficient way to solve high-complexity video codec.Due to its feedback loop, traditional video coding framework can improve thecoding efficiency in great extend. However, the dependency of the time correlationof video sequences is too high to realize parallelism under such structure. A novelvideo parallel coding framework is proposed. It includes three models: parallelpreprocessing module, parallel motion estimation module and parallel codingmodule. Integer pixel motion estimation consumes most of the coding time and thelargest computational amount. The framework pulls it out of the feedback loop andmakes it work independently and parallelly to realize parallelism of space. There willbe a parallel preprocessing prior to the motion estimation modal, which can get therelated parameters used in pattern recognition and rate control, thus computationalamount can be reduced greatly. Coding rate in multi-processor platform can beimproved in the case that there will be no reduction of coding performances.Because that AVS+has its unique slice syntactic structure and its demands of3D andhigh definition videos, we can apply the novel coding structure to AVS+codec. Thespeedup rate through testing high definition sequences in the platform of multi-coreserver is up to12, which can meet the demand of real-time application. Theframework changes the traditional video coding feedback loop and realizes thecoding parallelism. Experimental results demonstrate that the proposed algorithmmakes full use of the computing ability of multi-core processor, and improves the code rate greatly in the case of high resolution video.Traditional rate control scheme has its limitation in the new parallel videocoding framework. A new parallel rate control is proposed. Through theexperimental data of PSNR and VBV buffers we can analyze that the new ratecontrol scheme can get a relative well PSNR and the conditions of buffer overflowand underflow also don’t happen. It meets the demand of real application. |
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