Image data is encoded into sync blocks of fixed length and maximum data volume by dividing a vertical interval of image data samples, such as a field or frame of samples, into a plurality of blocks and deriving the orthogonal transform of the image data samples in each block. A block of conversion coefficients...http://www.google.fr/patents/US5321440?utm_source=gb-gplus-shareBrevet US5321440 - High efficiency data compressed image encoding
