Syntax-constrained rate-distortion optimization for DCT-based image encoding methods

In this paper, we presented a novel and effective optimization method to achieve better trade-off between rate and distortion. The optimization is done at the encoder side alone and is transparent to the decoder. That is the quantized DCT coefficient set is optimzed with full syntax compliance and decoder compatibility. The proposed method determines both the positions and the retained values of quantized DCT coefficients according to the rate-distortion performance measured by the associating Lagrangian cost. Fast dynamic programming technique was developed to release the computation burden. All the experiments show that the proposed method consistently outperforms other existing optimization methods