Low complex deblocking filter decisions
The present disclosure relates to deblocking filtering, which may be advantageously applied for block-wise encoding and decoding of images or video signals. In particular, the present disclosure relates to an improved memory management in an automated decision on whether to apply or skip deblocking filtering for a block and to selection of the deblocking filter. The decision is performed on the basis of a segmentation of blocks in such a manner that memory usage is optimized. Preferably, the selection of appropriate deblocking filters is improved so as to reduce computational expense.
1. A decoding device decoding blocks of a frame, comprising:
a processor; and
a memory coupled to the processor;
wherein the processor performs the following:
dividing each of a first block and a second block that are separated by a first boundary into at least two groups of pixels along a line that is perpendicular to said first boundary, the first block including a first group of pixels and a second groups of pixels, the second block including a third group of pixels and a fourth group of pixels, and the first block and the second block being included in the frame;
first judging whether or not to apply a deblocking filter to pixels adjacent to the first boundary of the first block and the second block;
first selecting a first deblocking filter for deblocking pixels adjacent to the first boundary;
second judging whether or not to apply a deblocking filter to pixels adjacent to a second boundary, the second boundary being a boundary between a third block and one of the first block and the second block and perpendicular to the first boundary, the third block being different from the first block and the second block; and
second selecting a second deblocking filter for deblocking pixels adjacent to the second boundary,
wherein
the first group of pixels in the first block is adjacent to the third group of pixels in the second block, and the second group of pixels in the first block is adjacent to the fourth group of pixels in the second block,
in the first judging, only the pixels included in the first group of pixels in the first block and the third group of pixels in the second block are used, the first group of pixels in the first block and the third group of pixels in the second block being adjacent to the first boundary, and
in the first selecting, for the first group of pixels in the first block and the third group of pixels in the second block, one type of deblocking filter is selected as the first deblocking filter, from among a plurality of types of deblocking filters, using (i) sample pixels in the first group of pixels in the first block and (ii) sample pixels in the third group of pixels in the second block, and without using any (i) sample pixels in the second group of pixels in the first block and (ii) sample pixels in the fourth group of pixels in the second block.
2. The decoding device according to claim 1 ,
wherein one of the at least two groups of pixels includes a plurality of lines of pixels.
3. A decoding method for deblocking filtering of image blocks of pixels, comprising the steps of:
dividing each of a first block and a second block that are separated by a first boundary into at least two groups of pixels along a line that is perpendicular to said first boundary, the first block including a first group of pixels and a second groups of pixels, the second block including a third group of pixels and a fourth group of pixels, and the first block and the second block being included in the frame;
first judging whether or not to apply a deblocking filter to pixels adjacent to the first boundary of the first block and the second block;
first selecting a first deblocking filter for deblocking pixels adjacent to the first boundary;
second judging whether or not to apply a deblocking filter to pixels adjacent to a second boundary, the second boundary being a boundary between a third block and one of the first block and the second block and perpendicular to the first boundary, the third block being different from the first block and the second block; and
second selecting a second deblocking filter for deblocking pixels adjacent to the second boundary,
wherein
the first group of pixels in the first block is adjacent to the third group of pixels in the second block, and the second group of pixels in the first block is adjacent to the fourth group of pixels in the second block,
in the first judging, only the pixels included in the first group of pixels in the first block and the third group of pixels in the second block are used, the first group of pixels in the first block and the third group of pixels in the second block being adjacent to the first boundary, and
in the first selecting, for the first group of pixels in the first block and the third group of pixels in the second block, one type of deblocking filter is selected as the first deblocking filter, from among a plurality of types of deblocking filters, using (i) sample pixels in the first group of pixels in the first block and (ii) sample pixels in the third group of pixels in the second block, and without using any (i) sample pixels in the second group of pixels in the first block and (ii) sample pixels in the fourth group of pixels in the second block.
4. The decoding method according to claim 3 ,
wherein one of the at least two groups of pixels includes a plurality of lines of pixels.