An adaptive perceptual quantization algorithm for video coding

A novel adaptive quantization algorithm for video sequence coding which can reflect macroblock characteristics as well as the status of the output channel buffer is described. The exploit local perceptual characteristics in the macroblock, block-based visual activities are determined and used to decide the perceptual quantization scaling factor. By using the proposed scheme, coding distortion is uniformly distributed across the image and its visibility is further minimized. A simulation was performed by applying the proposed adaptive perceptual quantization scheme to an HDTV (high-definition television) coding system at a rate of about 0.35 b/pixel. The scheme was compared with a simple quantization method, which does not use perceptual local activity, in terms of subjective quality. It was observed that the proposed method achieved significant improvement in the perceptual image quality. >