【摘要】 为提高低延时低码率条件下的视频质量,提出一种H.264帧层和宏块层的码率控制算法,实现平滑主观质量和平稳缓冲区波动的一种新的权衡。帧层采用比例-积分-微分算法进行帧层码率分配;在宏块层建立一种新的基于运动外推的编码复杂度传播模型,在保证感兴趣区域具有平稳质量的前提下,在感兴趣区域和非感兴趣区域之间进行比特分配;在各区域中,根据编码复杂度传播模型,基于率失真优化选择宏块量化参数。仿真结果表明:和传统JM算法相比,感兴趣区域的质量波动可减少达35.5%～57.1%。该算法在保证较低缓冲区波动的前提下,具有平滑的主观视频质量。更多还原

【Abstract】 The video coding perceptual quality at low bit rates was enhanced by a rate control scheme that achieves a better trade off between consistent quality and smooth buffer occupancy.A proportional integral technique was used for the frame level rate control.The motion extrapolated coding complexity propagation model was used to allocate bits between the region of interest(ROI)and other regions while smoothing distortion in the ROI using rate and distortion optimized macroblock level bit allocation.Simulations show that the algorithm reduces ROI distortion fluctuation by 35.5%-57.1% compared with the rate control by the traditional JM algorithm at the same bit rate.更多还原