Extracting coding parameters from pre-coded MPEG-2 video

We investigate the problem of MPEG-2 video quality degradation due to re-encoding using different coding parameters. We examined the statistical properties of pre-coded video and discovered that the coding parameters can be recovered from pre-coded video because the compressed video is represented by a limited set of parameters. We present an algorithm to detect if a picture is intra-coded or original and extract coding parameters if the picture is intra-coded. We show with numerical results that the coding parameters can be effectively extracted from pre-coded video and used to reduce additional coding loss, thus greatly improving the performance of multiple-generation coding