A system for converting the color format of a digital video bitstream. The system accounts for the allowable formats of the pre- and-post-conversion bitstreams, including quantizer precision level, and whether luma and chroma data have separate quantization matrices, or share a common quantization matrix....http://www.google.com.au/patents/US6259741?utm_source=gb-gplus-sharePatent US6259741 - Method of architecture for converting MPEG-2 4:2:2-profile bitstreams into main-profile bitstreams
