Rate-Distortion Optimized Embedding

In this paper, we improve the performance of the embedded coder by reorganising its output bitstream in the rate-distortion (R-D) sense. In the proposed rate-distortion optimized embedding (RDE), the coding bit is first allocated to the coefficient with the steepest R-D slope, i.e. the biggest distortion decrease per coding bit. To avoid transmission of the position of the coded coefficient, RDE uses the expectation R-D slope that can be calculated by the coded bits that have already been transmitted to the decoder. RDE also takes advantage of the probability estimation table of the QM-coder so that the calculation of the R-D slope is just a lookup table operation. Extensive experimental results show that RDE significantly improves the coding efficiency.