一种基于分层B帧架构的高效比特分配算法

Effective Bit Allocation Algorithm for Hierarchical B-frames

随着分层B帧码率控制技术在SVC(可伸缩视频编码)中的广泛应用,视频编码的质量得到了很大提高,然而传统的H.264码率控制技术并未将B帧的比特分配考虑在内。提出一种基于分层B帧架构自适应调节B帧比特分配的码率控制算法,该算法研究了基于同一个图像组(GoP)中各时域层权重因子的自适应调节,为各时域层分配不同的目标比特;同时基于同一个时域层中各帧复杂度的不同,为各帧分配不同的目标比特。实验结果表明,与目前流行的分层B帧码率控制算法相比,该算法在比特控制误差并未降低的情况下,客观质量PSNR可提高0.1～0.4 dB。

Recently, the hierarchical B-frames coding is introduced into scalable video coding which can further improves the coding performance. However, most of conventional rate control algorithms aim to assign the target bits to P frames instead of B frames. In this paper, a novel bit allocation algorithm for hierarchical B-frames is proposed based on a hierarchical level rate control scheme. The hierarchical level rate control scheme is proposed to adaptively assign target bits of different levels in the same group of pictures （GoP） according to their weighting factors. Meanwhile, the algorithm allo- cates target bits to different frames in the same temporal level based on their complexity. Experiment results show that the proposed algorithm can in- crease the coding efficiency with 0. 1 ~ 0.4 dB PSNR compared with the-state-art algorithms.