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 second meeting during 21-28 July, 2010 at the itu-t premises in Geneva, ch

JCTVC-B067 [S. Sekiguchi, A. Minezawa (Mitsubishi), K. Iguchi, Y. Shishikui (NHK)] DCT-based noise filtering for intra prediction samples

This contribution reports experimental results on a noise filtering method to intra prediction samples, based on the iterative adjustment intra prediction (IAIP) mode proposed in JCTVC-A122. The IAIP mode tries to get better intra prediction samples especially for texture with moderate gradation by involving continuity between target prediction samples and neighboring reference samples. It applies DCT to an image region covering the block to be predicted and its neighboring decoded samples, then inversely transforms the coefficients after cutting off of some high frequency components. By repeating this process, characteristics of neighboring samples can effectively be incorporated into the prediction samples. In this contribution, we applied this idea for noise filtering on intra prediction sample generated by angular multi-dimensional intra prediction (ADI) modes, which has been included into TMuC. The proposed filtering just applies DCT once to an image region consisting of intra prediction samples derived from ADI process and its spatially neighboring blocks, then inversely transforms after cutting high frequency coefficients. The experimental result shows that the proposed approach could improve intra coding performance of ADI modes even without use of adaptive reference sample smoothing scheme.

Goal to improve prediction in top-right area of the predicted block. Approach is to use the DCT-domain prediction similar to JCTVC-B027 as post-processing of usual directional prediction, but not operated interatively (i.e. setting high-frequency components of the prediction block to zero effects a kind of noise suppression).

Simulations in JCTVC-A124 software (not TMuC or stripped 124 pre-TMuC). Average gain reported is 2.3% for high-resolution sequences (class B, A and 8Kx4K).

Gain seems not to be high, but the approach to apply de-noising or some kind of loop filtering in the intra prediction could be worthwhile (not necessarily in the DCT domain!) Compare to other contributions that go in similar direction.

Further study should be performed in context of loop/deblocking filters