Patent ID: 9094716
Filing Date: 2015-07-28
Classification: H04N

Abstract:
1. Method for coding a block of a picture belonging to a sequence of pictures, said block comprising pixels with each of which at least one picture data is associated comprising the following steps: a) determining a prediction coefficient DCpred of a DC coefficient of said block from a DC coefficient of at least one previously reconstructed reference block, b) determining, for each pixel of said block, a prediction value equal to Xn−Avg(Xn)+DCpred/R when said block is an INTRA block and to MV(Xref)−Avg(MV(Xref))+DCpred/R when said block is an INTER block, where: R is a proportionality coefficient, Xn are the previously reconstructed values of pixels of neighbouring blocks used for the prediction of said block, Avg(.) is the average function, Xref are the previously reconstructed values of pixels of reference blocks used for the prediction of said block, and MV(.) is a motion compensation function; c) calculating, for each pixel of said block, a residual value by subtracting from the picture data of said pixel the prediction value (Xpred) of said pixel, d) transforming said block of residual values by a first transform into a first block of coefficients, e) replacing, in said first block of coefficients, the coefficient DC by the difference between the product of said proportionality coefficient and said average of picture data of said block and said prediction coefficient, and f) quantizing and coding said first block of coefficient.