JVET-D0047 Extended deblocking-filter decision for large block boundary [K. Kawamura, S. Naito (KDDI)]

This contribution proposes an extension of both the deblocking filter decision and deblocking filter process for large block boundaries, which is a revised version from the JVET-C0049 proposal. In HEVC, both large transform blocks and large prediction blocks were introduced. When a large block is used for a smooth area where luma value is little varying and/or gradation, the blocking artefact becomes much visible on low bitrate. For improving the visual quality, this contribution proposes an extension of edge filtering decision and process only for a boundary of large blocks. Compared with the previous proposal, the proposed method is harmonized with the QTBT structure in JEM3.0 while it includes additional decision criteria.

Number of filtered samples for large blocks (>=16) is increased from 6 to 14.

The method has BD rate loss of 0.2% on average.

It was unclear if it gives a subjective benefit, but at the current meeting there was no possibility for viewing for this topic.

No interest was expressed by other experts.