Research And Applications Of Rate Control In Video Coding

One important issue in video coding is rate control, which refers to how to code a video so that the resulting bitstream satisfies a target bit rate. Generally one rate control is necessary in video communications for an accepted visual quality under some certain rate constraint because of the fact that overrating the output of a video coder can cause an undesirable traffic explosion and excess the capacity of channel while on the other hand uncontrolled reduction of the output bit rate of a video coder leads to unnecessary quality degradation and inefficient use of available bandwidth resources. How to find a set of coding parameters to achieve the video quality as good as possible while subject to a rate constraint is subject of rate control. In fact, rate control can be viewed as a kind of optimal problem and the desirable coding parameters are the solution of the optimal problem.In the introduction, first we give the answer to why rate control is needed. Then the general rate control diagram is illustrated and some rate control methods at present are presented also.The related background knowledge about rate control and some ideas of our rate control algorithm are discussed in chapter II. We first brief the MPEG-2 video coding standard and the H.263 standard. Then we introduce some common used rate model. Rate control algorithm of TM5 is expounded including the implementation steps and the limitations. So we put forward a new complexity measure that will be used in rate control algorithm in chapter III. Finally, the mathematical model and the implementation process of TMN8 are described and we present the idea for consistent picture quality, which is also the start point of chapter IV.Rate control based on content complexity is described in chapter III. According to the linear source rate model, a new content complexity is...