A distortion control scheme for allocating constant distortion in FD-CD video transcoder

Recently, FD (frame dropping)-CD (coefficient dropping) transcoding has been considered, mainly due to the low computational complexity and simple implementation. However, CD errors in the FD-CD transcoding scheme tend to be propagated and they have a significant effect on the qualities of decoded images. We derive the error characteristics incurred by CD operations and propose an effective estimation model that adaptively describes well the characteristics of propagation errors in the compressed domain. Furthermore, we apply the proposed model to distortion control achieving nearly constant distortion allocation among frames. Simulations show that the proposed model is quite accurate in estimating the overall distortions and is effectively applied to distortion control over a range of sequences with varying scene types.