Rate-Distortion Optimal Adaptive Quantization and Coefficient Thresholding for MPEG Coding

This paper presents an MPEG-2 compatible adaptive quantization algorithm that leads to the optimal encoding of I-frames in the sense of maximizing PSNR. It integrates three key features into a single Lagrangian optimization model: adaptive quantization including quantizer-change overhead consideration, coefficient thresholding, and a new coefficient amplitude reduction technique. Our results show that I-frames generated by the TM5 reference encoder are about 1.5-2.0 dB below the theoretical optimum