Patent ID: 8204114

Claim:
A direction detection algorithm for H.264/AVC intra prediction comprising the acts of: dividing a 4×4 block into four evenly-divided 2×2 sub-blocks and an inner 2×2 sub-block; computing average pixel values for the four evenly-divided 2×2 sub-blocks and an average pixel value for the inner 2×2 sub-block; finding four directions from edge assent rules, the pixel values and all of said sub-blocks; determining a main edge of the 4×4 block based on the four directions; selecting three prediction modes from the main edge and its adjacent directions; choosing mode 0 (90°), mode 1 (0°) and mode 2 (non directional mode, DC) as base prediction modes; determining unique ones of the selected prediction modes by determining if any of the selected prediction modes is the same as one of the base prediction modes; and using the unique ones of the selected prediction modes and the base prediction modes in intra prediction of the 4×4 block.