面向H.264SVC空域-时域可伸缩编码的码率分配算法

Bit Allocation Algorithm for Joint Spatial-Temporal Scalabilities in H.264 SVC

提出一种面向H.264 SVC空域时域可伸缩编码的码率分配算法。通过对SVC编码过程的分析,设计了一个两阶段基于模型的码率分配算法框架。在每一阶段中沿空域或时域可伸缩性方向上,码率分配问题都被描述为一个优化问题进行求解。在充分挖掘层次间相关性的基础上,提出空域、时域视频层的失真和码率模型。利用所得到的率失真模型,使用拉格朗日乘数法,求取该分配问题的最优数值解。实验结果表明,新的率失真模型所提供的高效码率分配算法,大幅度提高了现有参考代码JSVM的性能,其编码效率平均增益达1.22 dB。

A bit allocation algorithm on joint spatial-temporal（S-T） scalabilities layers is proposed for H.264 SVC.Taking account of the characteristic of SVC encoding procedure,a two-step model-based bit allocation scheme is developed.Along spatial/temporal scalability dimension in each step,the bit allocation issue is formulated as an optimization problem.Then,the rate and distortion（R-D） models for dependent spatial and temporal layers are derived separately,where the complicated inter-layer dependencies are sufficiently considered.Finally,using the Lagrange multiplier method,the proposed algorithm can be solved numerically with derived R-D models.Experimental results show that the new R-D models result in a highly efficient bit allocation scheme,which outperforms the JSVM benchmark by a significant margin,and the average coding gain achieves 1.22 dB.