H.264码率低和视频质量高的优越性能以增加编码计算的复杂度为代价,如何开发适用于多核处理器平台的并行编码算法是提高其编码速度的重要研究内容,对于满足高清视频实时传输和大规模共享具有十分重要的意义.利用H.264开源编码器项目X264,在片级和数据级并行编码算法的基础上,通过分析图像帧之间的参考关系,提出并实现了B帧个数可变的帧级并行算法;根据宏块之间的参考关系,设计了一种类似流水线的宏块级并行方法;基于Intel同构多核平台,提出融合帧级、片级、宏块级和数据级4种不同粒度的并行编码方案,开发了H.264多粒度并行编码器.实验结果表明,在码率增加不大的情况下,H.264多粒度并行编码器可以很好地提升编码加速比,视频编码质量符合高质量的要求.
As a new generation video coding standards, H. 264 requires more intensive computation than before to achieve high coding performance. With the continuous development of multicore processors, the development of the multi-grain parallel H. 264 encoder has great significance to meet the requirements of video real-time transmission and large-scale sharing. Based on the open-source H.264 encoder project X264, an adaptive B-frame frame parallel algorithm is proposed through analysis of the dependency among the referent frames. According to the reference of related macroblocks, a macroblock-level parallel approach is designed in assembly-line fashion. A multi-grain parallel H.264 encoder is implemented on the homogeneous multi-core platform. This eneoder efficiently combines four parallel grains, including frame, slice, macroblock and data level. Experimental results demonstrate that the encoding speedup is improved to a large extent, without obviously increasing bitrates. The high-quality video is kept in the encoding process.