Image and video codecs don't actually use the fourier transform as presented in the article, they use the DCT. Check out the example section on Wikipedia: https

Image and video codecs don't actually use the fourier transform as presented in the article, they use the DCT. Check out the example section on Wikipedia: https://en.wikipedia.org/wiki/Discrete_cosine_transform https://en.wikipedia.org/wiki/Discrete_cosine_transform The JPEG article also has a very good, step by step example of the DCT, followed by quantization and entropy coding: https://en.wikipedia.org/wiki/JPEG https://en.wikipedia.org/wiki/JPEG