面向分层B帧编码的帧级别码率控制算法

Frame Layer Rate Control for Hierarchical B Pictures Coding

摘要: 为了更有效地支持分层B帧编码结构, 提出了一种帧级别码率控制算法.首先, 根据编码内容的复杂度和可用信道带宽自适应选择最佳初始量化参数;其次, 根据分层B帧的编码结构特点, 分别从图像组级别、时域层级别以及帧级别进行码率分配;最后, 采用二次码率-量化模型计算量化参数并进行调整.实验结果表明, 该算法与传统的码率控制方法相比, 在提高码率控制精度的同时, 能带来最高1.5 dB的峰值信噪比增益.

Abstract: A frame layer rate control algorithm is proposed to better support the hierarchical B pictures coding structure.First, the initial quantization parameter (QP) is adaptively selected according to the complexity of video content and the available channel bandwidth.Second, taking the feature of the hierarchical coding structure into consideration, target bit budgets of the group of picture (GOP) layer, the temporal layer and the frame layer are allocated.Finally, the quadratic rate-quantization (R-Q) model is conducted to calculate the quantization step, and the final QP of the current coding frame is determined after further adjustment.Experimental results demonstrate that, compared with the traditional rate control algorithm, the proposed algorithm can successfully bring peak signal-to-noise ratio (PSNR) increment up to 1.5 dB while achieving more precise rate control result.