Prediction of transform coefficients for image compression

Abstract From the Canadian patent

A block transform-based digital media codec uses a transform coefficient prediction that takes into account a dominant directionality of the digital media data (e.g. an image with strong horizontal or vertical features) and , further operates compatibly with a two-stage transform. For DC and DCAC coefficients from an inner stage transform of a macroblock the codec , calculates and compares directionality metrics based on inner stage transform DC coefficients of neighboring macroblocks to determine dominant directionality. For DCAC coefficients from an outer stage transform of blocks within the macroblock, the codec calculates and compares directionality metrics based on the inner …