A buffer control algorithm for CBR video transcoding

We propose a bit rate control algorithm for video transcoding, based on a dynamic buffer strategy. We show that the bit rate reduction ratio used for transcoding CBR bit streams should not follow the constant relation given by the input and output channel capacities but follow a variable function dependent upon the picture type instead. Based on a simulation study, the influence of the dynamic buffer occupancy on the picture quality is discussed and the proposed algorithm is shown to be capable of achieving transcoded picture quality comparable to that of single-stage encoding.