TM5码率控制算法的分析和改进

Analysis and Improvement of TM5 Rate Control Algorithm

众所周知,MPEG-2的TM5码率控制算法是一种优秀的码率控制算法,由于它引入了复杂度分析、码率分配、码率控制、自适应量化等概念方法,从而可以较准确地控制视频流的输出码率,鉴于该算法仍有许多不足,为此在对TM5码率控制算法的自适应量化公式的不足之处和码率控制部分的优点和局限性进行分析的基础上;提出了TM5码率控制算法的一种改进方法.实验结果表明,该改进方法不但有效降低了原TM5码率控制算法的复杂度,同时获得了0.8～1.8dB的增益.

This paper gives a study on MPEG-2 Test Model(TM5) rate control algorithm.In this algorithm,the conceptions and methods of complexity analysis,rate allocation,rate control,adaptive quantization are introduced for the first time in the matter of video rate control.And these can be used to control the bit rate of out video accurately.But there are still many deficiencies in it.In this paper,TM5 rate control algorithm is analyzed,which includes mainly the equations of rate control and adaptive quantization.Firstly,the problem of adaptive quantization's equation is introduced and discussed.Then the formula of rate control is analyzed step by step and the final conclusion is that the principle of rate control is integral control.At last,based on the discussion above,an improvement with lower complexity is proposed,which gains 0.8～1.8dB.