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 the 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, the performance gap between DCT and wavelet based coding is within one dB in PSNR at the same bitrate. This is in contrast to the common perception that the wavelet transform is much superior to the DCT for image compression. For video coding, the advantage of using the wavelet transform over the DCT is even less pronounced.