A comparative study of DCT and wavelet based coding
We study the performance difference of the discrete cosine transform (DCT) and the wavelet transform for both image and video coding, while comparing other aspects of the coding system on an equal footing. Based on the state-of-the-art coding techniques, we point out that, for still images, wavelet outperforms DCT with a coding gain of about one dB in PSNR. For video coding, the advantage of wavelet schemes is less obvious. We believe that image and video compression algorithms should be addressed from the overall system viewpoint. Quantization, entropy coding, and paying attention to details are more important than spending all the efforts on optimizing the transform.