Conversion of image data from subsampled format to clut format

摘要

A method, apparatus, and system for generating an image from subsampled, three-component image data. First and second components of the image data are processed to generate a dither index to a dither lookup table. The third component of the image data is dithered. CLUT index data is then generated using the dither data from the dither lookup table and the dithered third-component data. The CLUT index data may then be used to generate the image. In a preferred embodiment, a 14-bit dither index to a 16K dither lookup table is generated from the U and V components of a (4×4) block of YUV9 data. The Y components are dithered and then processed with the appropriate dither lookup table data to generate 16 CLUT index values for the (4×4) block. The dithering and processing is preferably performed on a row-by-row basis in a pseudo- SIMD fashion.