Of itu-t sg16 wp3 and iso/iec jtc1/SC29/WG11

6.1.2RCE1 related (inter-component decorrelation)

JCTVC-M0230 Non-RCE1/Non-RCE2/AHG5/AHG8: Adaptive Inter-Plane Prediction for RGB Content [T. Nguyen, A. Khairat, D. Marpe (Fraunhofer HHI)]

This document describes an adaptive inter-plane prediction scheme intended for RGB materials, especially for screen content. The proposed technique operates as an in-loop operation on the prediction residuals. The proposed scheme involves a class of predictors each requiring one addition and one bit shift operation. Experimental results are asserted to show improvement relative to fixed color transformation schemes, especially when considering screen content and higher bit rate operation points.

This is only for 4:4:4, specifically targeted for RGB.

The results measurements were reported in a different way than in most tests we have used.

The results were not shown relative to ordinary coding in the YUV domain.

A syntax element per chroma TB is used to indicate whether to predict the chroma residual from the luma residual and how much to shift the luma residual if applied.

The bit depth of the chroma is increased by 1 bit during the decoding process, prior to picture reconstruction and loop filtering.

The encoding time is significantly increased, due to the checking of the flag values. The decoding time is significantly increased, which was suggested to be due to post-decoding conversion.

The technique is proposed for both intra and inter.

The scheme seemed difficult to analyze. It was suggested to have AHG study on how to measure performance of such techniques that have cross-component interactive effects.

A cross-checker expressed an interest in comparing the technique to YUV coding with bit depth increase.

It was also suggested to check whether this works on YUV coding – e.g. comparison to LM chroma on intra was suggested.

Further study in CE is recommended.