Patent ID: 7933337

Claim:
A method of encoding digital media data using a predictive coding of transform coefficients, the digital media data comprising digital video or image data, the method comprising: applying a first stage transform to blocks in a current macroblock of the digital media data; grouping DC coefficients resulting from the first stage transform into a group of DC coefficients; applying a second stage transform to the group of DC coefficients to produce a set of transform coefficients for the current macroblock including a DC coefficient of the current macroblock; performing predictive coding of at least some of the transform coefficients, the predictive coding comprising: determining whether one of at least two directions of the digital media data in a locality of the current macroblock is dominant, wherein a direction is considered dominant when a directional difference for the direction is more than a weighting factor times that of another direction; when one of the at least two directions is determined to be dominant in the locality of the current macroblock, selecting a predictor of the DC coefficient of the current macroblock according to the determined dominant direction; and encoding the DC coefficient of the current macroblock relative to its predictor.