The Joint Collaborative Team on Video Coding (jct-vc) of itu-t wp3/16 and iso/iec jtc 1/ sc 29/ wg 11 held its tenth meeting during 11-20 July 2012 at the City Conference Centre (ccc), a k. a

JCTVC-J0409 Crosscheck of JCTVC-J0181: AHG6: On deblocking filter parameters [D.-K. Kwon (TI)] [late]
JCTVC-J0445 Cross check of TI’s suppression of blocking artifacts at 32x32 transform boundaries [I. S. Chong, M. Karczewicz (Qualcomm)] [late]
JCTVC-J0286 AHG6: Adaptive deblocking filtering [A. Norkin (Ericsson)] [late]

The document studies a problem with blocking artifacts in the Riverbed, WestWindEasy and China Speed sequences and proposes modifications to HM7.0 that fix these problems. The proposed modifications reportedly reduce the blocking artifacts on the Riverbed, China Speed and West Wind Easy sequences and also reportedly improve the visual quality on the sequences in the common test conditions. The proposed modifications result in the following changes in BD-rate: (0.1%, 0.0%, 0.1% and −0.1%) on Main profile and (0.3%, 0.2%, 0.6%, 0.2%) on HE10 configuration, the decoding time is similar to that of the anchor. The modifications do not include sending additional parameters to the deblocking filter.

Proposed solution 1: Reduce intra boundary smoothing for horizontal, vertical and DC modes (change to intra prediction) in case of smaller intra blocks

Proposed solution 2: Apply stronger filter to larger intra prediction blocks, modify tc offset for 32x32 boundary.

Proposed solution 3: Apply stronger filter by allowing larger variations close to the block boundaries, e.g. such that deblocking is also useful for inclined surfaces (criterion: keeping the 2^nd derivative constant instead of 1^st derivative).

Several experts expressed the opinion that the amount of changes in this proposal is fairly high and the proposal has not thoroughly been studied as it became available late.