Deblocking filtering

A deblocking filter unit for reducing blocking artifacts at a block boundary between a block of multiple pixels and a neighboring block of multiple pixels in a video frame, comprising:

• a first offset calculator configured to calculate a first offset to be equal to (9×(q0−p0)−3×)q1−p1)+8)>>4, wherein >> denotes a right shift operation, p0 denotes a pixel value of a pixel closest to said block boundary in a line of pixels in said block, wherein said line of pixels is perpendicular to said block boundary, p1 denotes a pixel value of a pixel next closest to said block boundary in said line of pixels, q0 denotes a pixel value of a pixel closest to said block boundary in a corresponding line of pixels in said neighboring block, wherein said corresponding line of pixels is perpendicular to said block boundary, and q1 denotes a pixel value of a pixel next closest to said block boundary in said corresponding line of pixels;
• and
• a pixel value modifier configured to modify said pixel value p0 of said pixel closest to said block boundary in said line of pixels by adding said first offset to said pixel value p0 of said pixel closest to said block boundary in said line of pixels to form a modified pixel value p0′ of said pixel closest to said block boundary in said line of pixels and to modify said pixel value q0 of said pixel closest to said block boundary in said corresponding line of pixels by subtracting said first offset from said pixel value q0 of said pixel closest to said block boundary in said corresponding line of pixels to form a modified pixel value q0′ of said pixel closest to said block boundary in said corresponding line of pixels.

A computer program product comprising a non-transitory computer readable medium and a computer program stored on said computer readable medium, said computer program for reducing blocking artifacts at a block boundary between a block of multiple pixels and a neighboring block of multiple pixels in a video frame, said computer program comprising code means which when run on a computer causes the computer to:

• calculate a first offset to be equal to (9×(q0−p0)−3×( q1−p1)+8)>>4, wherein >> denotes a right shift operation, p0 denotes a pixel value of a pixel closest to said block boundary in a line of pixels in said block, wherein said line of pixels is perpendicular to said block boundary, p1 denotes a pixel value of a pixel next closest to said block boundary in said line of pixels, q0 denotes a pixel value of a pixel closest to said block boundary in a corresponding line of pixels in said neighboring block, wherein said corresponding line of pixels is perpendicular to said block boundary, and q1 denotes a pixel value of a pixel next closest to said block boundary in said corresponding line of pixels;
• modify said pixel value of said pixel closest to said block boundary in said line of pixels by adding said first offset to said pixel value of said pixel closest to said block boundary in said line of pixels;
• and
• modify said pixel value of said pixel closest to said block boundary in said corresponding line of pixels by subtracting said first offset from said pixel value of said pixel closest to said block boundary in said corresponding line of pixels.