A New Rate Control Algorithm In Frame And Macroblock Layer Under Low Bit

In order to get a better picture using limited bits ,an effective rate control algorithm is indispensable . In G012, only a target bit is allocated to a frame before coding it, but the difference between target and real bit is not processed; MAD predicition is only operated using linear prediction, so precision degree is not high. This paper addes a frame compensation algorithm and study a new macroblock MAD prediction algorithm:the Big-Small triangle prediction algorithm.Through simulation experiments, it proves that the new algorithm is better.The introduction mainly introduces rate control's present research situation in home and abroad ,and the major research content of this text.Some basic knowledge is mainly the correlation technique introduction of rate control: it mainly introduces the frame rate control technique and macroblock layer MAD's prediction technology .Frame layer compesation algorithm mainly aimes at the situation when real bits is bigger(smaller) than target bits for several frames even more frames. In order to settle the problem , bits compensation algorithm is given. When the number of continuous frames is not so more, bit compensation is adopted; otherwise, the quantification parameter will be adjusted. Experiments prove that the improved algorithm's PSNR is higher, the real buffer bufferfullness is closer to the target bufferfullness, and the real bit is closer to the target bit.The improved macroblock MAD predicition algorithm aims at former algorithm's lower prediction precision . In order to settle the problem , current malblock MAD's prediction uses more malblocks combinating with malblock correlation , and the malblocks are devided into two kinds : neithboring current malblock and not. I use defferent ways towards defferent malblocks . Experiments prove that the improved algorithm's PSNR is higher, the real bufferfullness is closer to the target bufferfullness, and the real bit is closer to the target bit.Anyway, the improved algorithm has a better performance indicators, and it proves that the improved algorithm is better.