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-J0421 Cross-check of Removal of the 8x2/2x8 coefficient groups (J0256) by Qualcomm [C. Rosewarne, M. Maeda (Canon)] [late]
JCTVC-J0281 Additional horizontal and vertical scan for transform coefficients [C. Auyeung (Sony)]

This contribution proposes two proposals to add horizontal and vertical scans to HM7 to improve coding efficiency. In the proposal A, horizontal and vertical scan is added to the coding of 8x8 chroma transform coefficients. This required one character change in the HM7 source code, and it resulted in −0.2% to intra main chroma BDR and −0.1% to intra HE10 chroma BDR. In proposal B, the horizontal and vertical scan is added to all transform sizes. It resulted in BDR of −0.1% for luma intra main and luma intra HE10. It also resulted in BDR or −0.3% to −0.4% for chroma intra main and chroma intra HE10.

Method 1 applies current 2x8 / 8x2 subblock schemes also for chroma (0% gain in luma, 0.2% in chroma)

Method 2 applies 1x16 / 16x1 also for 16x16 and 32x32 and everything also for chroma (0.1% gain in luma, 0.4% gain in chroma)

Q: Would it be desirable to combine method 1 with J0256 (i.e. use the new hor/ver 4x4 sub-blocks also for chroma in 8x8 case)

• 
  no results available on such combination (but CE gain can be expected to be irrelevant)
  
• 
  would the current contexts work?
  
• 
  what would be the benefit in terms of implementation?
  

Ccould be further studied.

It was verbally reported that such a combination provides similar gains in chroma.

No action.

JCTVC-J0368 Cross-check of additional horizontal and vertical scans (JCTVC-J0281) [J. Sole (Qualcomm)] [late]