Research Of Real-time Low-velocity Rate Control Algorithm Based On H.264

The main target of video compression code is to limit the distortion of code under the condition of restricted rate. In order to get the most optimized compression efficiency, ensure the code data transfer successful in the channel, and obtain the best video quality. The distorted optimization and the rate control has the important status. The purpose of rate control is to adjust the output code stream, thereby make use of the bandwidth effectively, and achieve the high steady image quality at the same time.This paper first discuss the rate control theory foundation, then make an research to the current classic rate control algorithm, such as TM5, TMN8, VM8, H.264/AVC of JVT, and the improved rate control algorithm of H.264/AVC, we find that the algorithm of the resolution is just to do simply average distribution, and has not considered the current code frame or the complexity of the basic unit when carries on the distribution of frame level target bits and the basic unit level bits. When making the computation of the current frame or the texture bits of the basic unit, the current frame or the head information of the basic unit bits will be replace by the former frame or the relevant former one, and it just utilizes time relevance, not spatial relevance. In the resolution, there is not the mechanism of skip-frame control, however, the buffer maybe overflow for the strong motility sequence because of the small buffer under the real-time low rate application condition. In view of the deficiency of JVT—H017 of the H.264/AVC rate control algorithm, this paper makes the improvements as follows:It proposes the target bit distribution based on the frame complexity, taking the weighted combination of MAD_ratio,i and MAD_drop-ratio,i as the target of weighing frame or the basic unit complexity. The experimental result indicates that the distribution accuracy has an enhancement with the compare of H017, and has the better image quality.It proposes a forecasting scheme based on the basic unit head code of the time-space relevance, which uses the head code of the unit before the current basic...