率失真优化技术在视频优化编码中起着重要的作用,广泛地应用于宏块模式决策,优化量化等编码模块中.本文将率失真优化编码与码率控制结合起来进行研究,通过对率失真关系的分析,提出了基于率失真优化的复杂度可分级码率控制算法,并根据缓冲区操作模型的位分配约柬条件调整码率控制的位分配过程,从而使得该算法在达到码率控制的同时也能取得较高的编码效率,并能保证缓冲区不会发生溢出,然后结合场景变换、图像内容分类等主观质量问题研究,提出一种恒定质量码率控制编码算法.
Rate distortion optimization technique plays an important role in video coding, which is widely used in many video coding modules, such as macroblock mode decision, quantization optimization, etc. In this paper, rate distortion optimization coding and optimal rate control are studied jointly. First, according to the analysis on the relationship between rate and distortion, a complexity scalable rate control is proposed. The proposed rate control algorithm can achieve better coding efficiency while with accurate target bit rate; second, buffer constraint for the bit allocation of rate control is studied, and the bit allocation process is adjusted to meet the buffer constraint, so that the proposed rate control algorithm can guarantee that the buffer never overflows or underflows; finally, a constant quality rate control algorithm is developed based on the research on some subjective quality issues, such as scene change detection, macroblock classification, etc.