Deringing filter for video coding

A device for filtering a picture of a video signal, wherein said picture comprises pixels, wherein

• said device is configured to modify a pixel value of a pixel by a weighted combination of said pixel value and at least one spatially neighboring pixel value, wherein the weighted combination is obtained based on (i) a pixel distance between said pixel and a neighboring pixel, (ii) a pixel value difference between said pixel value and a neighboring pixel value of said neighboring pixel, (iii) a spatial parameter (σd), and a range parameter (σr), wherein
• said spatial parameter depends on (i) at least one of a width of a transform block and a height of said transform block and (ii) at least one of a prediction type of a block of pixels in said picture, a picture type of said picture, and a slice type of a slice in said picture,
• said block of pixels comprises said pixel,
• said slice comprises said pixel,
• said spatial parameter σd=p−A×0.025,
• A is selected from one of a minimum of said width of said transform block and said height of said transform block;
• a maximum of said width of said transform block and said height of said transform block;
• a mean of said width of said transform block and said height of said transform block;
• said width of said transform block;
• and said height of said transform block, and
• p is defined based on said at least one of said prediction type, said picture type, and said slice type.

A computer program product comprising a non-transitory computer readable medium storing computer program instructions, which when executed by at least one processor, cause said at least one processor to modify a pixel value of a pixel by a weighted combination of said pixel value and at least one spatially neighboring pixel value, wherein the weighted combination is obtained based on (i) a pixel distance between said pixel and a neighboring pixel, (ii) a pixel value difference between said pixel value and a neighboring pixel value of said neighboring pixel, (iii) a spatial parameter, and (iv) a range parameter, wherein

• said spatial parameter depends on (i) at least one of a width of a transform block and a height of said transform block and (ii) at least one of a prediction type of a block of pixels in said picture, a picture type of said picture, and a slice type of a slice in said picture,
• said block of pixels comprises said pixel,
• said slice comprises said pixel, and
• said range parameter depends on one of a quantization parameter of said picture, a quantization parameter of said slice, and a quantization parameter of said block of pixels.