MPEG Video Bit-Rate Shaping Technique Using Smooth-Transcoding Algorithm

In this paper we propose an algorithm to adjust the transmission bit-rate of variable-bit-rate (VBR) MPEG video data by using a combination of transcoding and bit-rate smoothing algorithm. The algorithm works by smoothing out the bit-rate of high variance MPEG video data and when necessary transcodes some video frames in order to keep the video transmission bit-rate below a determined threshold value. This technique is useful for a live video streaming application in which an originally high-quality VBR video data for broadband users must also be delivered to other type of users where their allowed bit-rate and its variation is tightly constrained, such as mobile phone users, without sacrificing the quality of video images too much. Quality degradation caused by transcoding can be reduced by the smoothing process, which will make the number of frames required to be transcoded can be much lower than doing transcoding solely. Depending on the threshold value, our experiment results show that the number frames needed to be transcoded can be reduced significantly.