Motion-compensated video coding with adaptive perceptual quantization

The authors address the problem of adapting the Motion Picture Experts Group (MPEG) quantizer for scenes of different complexity (at bit rates around 1 Mb/s), such that the perceptual quality of the reconstructed video is optimized. Adaptive quantisation techniques conforming to the MPEG syntax can significantly improve the performance of the encoder. The authors concentrate on a one-pass causal scheme to limit the complexity of the encoder. The system employs prestored models for perceptual quality and a bit rate that have been experimentally derived. A framework is provided for determining these models as well as adapting them to locally varying scene characteristics. The variance of an 8×8 (luminance) block is basic to the techniques developed. Following standard practice, it is defined as the average of the square of the deviations of the pixels in the block from the mean pixel value