Adaptive de-blocking filtering apparatus and method for MPEG video decoder

A method for reducing a blocking artifact in a video stream, the method comprising:

• calculating an activity value representing local activity around a block boundary between a plurality of adjacent blocks in the video stream;
• determining a region mode to be one of active region, smooth region, or dormant region for the block boundary according to the activity value;
• and
• filtering a plurality of pixels around the block boundary according to the region mode and the quantization parameters (QPs) of the adjacent blocks, wherein the filtered pixels are further refined according to the quantization parameters (QPs) of the adjacent blocks, or wherein symmetric filters or asymmetric filters are used to filter the pixels according to the quantization parameters (QPs) of the adjacent blocks;
• wherein:
• if at least one of the adjacent blocks is an intra-coded block:
• if the activity value is greater than a first threshold, determining the region mode to be an active region;
• if the activity value is less than the first threshold but greater than a second threshold, determining the region mode to be a smooth region;
• and
• if the activity value is less than the second threshold, determining the region mode to be a dormant region;
• and
• if none of the adjacent blocks are intra-coded blocks:
• if the activity value is greater than a third threshold, determining the region mode to be an active region;
• if the activity value is less than the third threshold but greater than the second threshold, determining the region mode to be a smooth region;
• and
• if the activity value is less than the second threshold, determining the region mode to be a dormant region.