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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。
In order to improve the video quality under low bit-rate and low bit-rate conditions, a rate control algorithm of H.264 frame and macroblock layer is proposed to achieve a new trade-off between smooth subjective quality and smooth buffer fluctuation. The frame layer uses rate-integral-differential algorithm to allocate the frame rate, and a new propagation complexity model based on motion extrapolation is built at the macroblock level. Under the premise of ensuring the stable quality in the region of interest, Bit allocation between regions of interest and non-regions of interest; in each region, the macroblock quantization parameters are selected based on the rate-distortion optimization according to the coding complexity propagation model. The simulation results show that compared with the traditional JM algorithm, the fluctuation of the region of interest can be reduced by 35.5% ~ 57.1%. The algorithm has a smooth subjective video quality under the premise of ensuring low buffer fluctuation.