Color space compatible coding framework for YUV422 video coding

A new video coding framework for YUV422 video sources is proposed in this paper. It features color space compatibility to the more popular YUV420 syntax. Specifically, the chrominance components are separately into two parts and coded differently. The first part, together with the luminance component, conforms to the YUV420 layout and is coded the same way as a normal YUV420 video to produce a YUV420-compatible base bit stream. The second part, i.e., the remaining chrominance components, is coded to generate an enhancement chrominance bitstream for improving the chrominance quality. This is in sharp contrast to the YUV422 coding method of MPEG-2/4 standards where all the chrominance are coded together and in the same way. Consequently, the resulting YUV422 bitstream can be easily converted to a YUV420 bitstream by simple truncation instead of undergoing an expensive transcoding process. New coding modes are also introduced for more efficient coding of the enhancing chrominance components. Performance-wise, the new framework also outperforms existing methods thanks to the new coding modes introduced.