Patent ID: 8787449

Claim:
An apparatus, comprising: (a) a computer configured for receiving encoded video signals; and (b) programming executable on said computer for processing said encoded video signals by performing one or more steps comprising: (i) performing entropy decoding; (ii) reconstructing macroblocks using inverse quantization, inverse transformations, and prediction to reconstruct each macroblock; (iii) executing a deblocking filter; (iv) executing a quadtree based adaptive loop filter having separable filters for P and B pictures; (v) wherein said separable filters are separable two dimensional (2D) filters determined as a product of a one-dimensional (1D) vertical filter and a one dimensional (1D) horizontal filter; (vi) wherein said 1D horizontal filter and said 1D vertical filter are initially determined from a non-separable 2D filter, followed by iteratively minimizing error for pixels within ON regions of a quadtree structure of said quadtree based adaptive loop filter; (vii) wherein said minimizing error is performed by determining a matrix and a cross correlation that assumes said 2D separable filter is not zero phase, and performing a transposition on the 2D separable filter and cross correlation; and (viii) outputting a decoded video signal.