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

5.15.4Coefficient level coding

JCTVC-J0095 AHG5: Pairwise Coding of Greater-than-1 Flags [N. Nguyen, D. He, G. Martin-Cocher (RIM)]

This document applies the concept of pairwise coding to the coding of greater-than-1 flags to improve the worst case throughput. It is reported that the pairwise coding method improves the worst case throughput from 1.875 to 1.625 context-coded bins per transform coefficient. Moreover, it allows two greater-than-1 flags to be coded in parallel and reduces the average number of context-coded bins per transform coefficient by between 4.5% and 8.5%. These benefits come at a cost of 6 additional contexts. The pairwise coding method presents opportunities for further study with respect to its interaction with intra transform skipping and RDOQ.

For information only – work not complete yet.

Some interference with transform skip – loss observed for class F.

One expert mentions that in general it may be desirable to also look at RDOQ off cases.