A reversible Discrete Cosine Transform (DCT) is described. The reversible DCT may be part of a compressor in a system. The system may include a decompressor with a reversible inverse DCT for lossless decompression or a legacy decompressor with an inverse DCT for lossy decompression....http://www.google.fr/patents/US6466699?utm_source=gb-gplus-shareBrevet US6466699 - Reversible DCT for lossless
