一种单通道VBR码率控制算法

A Single-Pass VBR Rate Control Algorithm

本文提出了一种低计算复杂度的VBR码率控制算法 ,它不需要对视频序列进行预先分析或多次编码 .该算法的主要思想是根据压缩码流统计信息 ,建立码率 -失真模型 ,计算目标比特开销 ,然后通过一个反馈机制在帧层调节量化因子 ,使得目标比特预算满足缓冲区约束条件 ,并尽可能地维持量化因子的稳定 .仿真结果表明 ,本文提出的方法不仅能够保证总体比特预算和缓冲区约束 ,获得相对稳定的视频质量 ,特别是对场景切换也有很强的适应性 ,而且实现简单 ,运算复杂度低 。

Rate control is a key module in a video encoder, and plays an important role in quality of video services.This paper provides a frame layer variable bit rate (VBR) rate control method without pre analysis and pre coding.Quantization parameters (QPs) are initialized in frame layer according to previous coding statistics firstly;then target bit is calculated according to rate distortion (R D) model,and a feedback mechanism regulates QPs and accommodates the target bit to buffer constraints.Simulation results show that the proposed method can not only meet the global bit budget and buffer conformance,but also result in a constant picture quality.Additionally,its low computational complexity makes it applicable to real time video coding.