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-B112 [J. Zhao, A. Segall (Sharp Labs)] Parallel prediction unit for parallel intra coding

The concept of a parallel prediction unit (PPU) is proposed within the Test Model under Consideration (TMuC) design. The goal of the parallel prediction unit is to define a group of pixels that are intra-coded, and where the intra-coding may be done in a parallel fashion. This extends previous work on parallel intra-prediction for a H.264/AVC-like macro-block to the TMuC design. Parallelization is achieved by partitioning the intra-coded blocks into two sets and predicting the first set completely from the pixels bounding the PPU. The second set of blocks is then predicted from the reconstructed, first set of blocks. To be clear, blocks within each set are predicted in parallel. Results are reported using TMuC 0.3 where it is asserted that the parallelism results in negligible impact on coding efficiency. For example, the coding efficiency impact for 1080p sequences (hierarchical B) is 0.012dB or less than 0.5%

Refers to previous proposal JCTVC-A105: First-pass and second-pass blocks arranged as checkerboard, where the second pass allows to perform prediction from the right and bottom as well.

Implemented in TMuC 0.48% BR increase for hier. B, and 0.25% for IPPP, and 0.5% for intra-only coding (latter only for 16 frames per sequence). (Results for high resolution – slightly higher for small resolution)

Comments: Parallel processing also possible with diagonal stripe processing; needs to be clarified whether high amount of parallelism at MB level is necessary, or whether this has to be paid off against other complications (of this specific algorithm)

Question: Would the checkerboard become visible?

TE to be established, provided that at least one other interested party is found