A new rate control of MPEG video encoding for enhancing local image area definition

In normal MPEG video encoding, the definition of the overall image is uniform. But in some applications, such as surveillance video recording systems, long-distance medical treatment video transmission system etc., people usually only pay attention to a part of the image area. In such applications, we can decrease the video bit rate by keeping the local image area high definition and the other image area low definition to save disk space or bandwidth. In this paper, we developed a new bit rate control algorithm suitable for MPEG video encoding. Using this algorithm, it is very easy to design two different definitions in one image, a higher definition for the more important part of the image area and a lower definition for the less important part. Experiments show that the algorithm is also very practical for hardware real time encoding when applied to the DEC 21230 MPEG-1 encoding chip.