A method for computing a prediction value, for a block X representative of image data, the method comprising: determining whether any of the following are outside of a boundary of a video object plane: a block A, horizontally adjacent to and left of the block X; a block B, vertically adjacent to and above the block A; and a block C, vertically adjacent to and above the block X; setting a DC coefficient for any of the block A, the block B and the block C that is outside the boundary of the video object plane; identifying a DC coefficient for any of the block A, the block B and the block C that is not outside the boundary of the video object plane; wherein the setting and identifying result in one DC coefficient for the block A, DCA, one DC coefficient for the block B, DCB, and one DC coefficient for the block C, DCC; and computing, after the setting and the identifying, a prediction value for the block X, wherein the only DC coefficients that are used in the computing are the DCA, the DCB, and the DCC.
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