Low-complexity rate-distortion optimal transcoding from MPEG-2 to MPEG-1 in DCT-domain

Transcoding is now widely used in many multimedia applications. This paper proposes a low-complexity rate-distortion optimal transcoding algorithm from MPEG-2 to MPEG-I in DCT-domain where spatial resolution reduction is involved. We jointly optimize transcoding parameters to select independently a across type, reused motion vector and quantization parameter for each individual MB in a frame by exploiting correlations between the input and output video and making use of try-and-error search method. The experimental results show that our method achieves improvement of average 1.4 dB peak signal-to-noise ratio (PNSR) over TM5 slightly increase in computational complexity.