Valencia JCT-VC and MPEG Meetings
NGCodec was at the JCT-VC/MPEG Meeting in Valencia to help the industry to continue with the development of the HEVC standard. This was a busy meeting where we did substantial work over 9 days. JCT-VC finished the work on version 2 Range Extensions (RExt) of HEVC and some further enhancements related to scalability SHVC. They were a number of additional MPEG activities that were conducted outside JCT-VC.
The work on HEVC version 2 was very active at this meeting, we made some small changes on some of the techniques that were present at the previous working draft and finished the profile definition. The version 2 of the specification was finalized at this meeting. And a new version of the HEVC specification including some small errata and the RExt changes will be issue shortly after this meeting, including the following new profiles: Main 4:2:0 12 bits, Main 4:2:2 10 bits, Main 4:2:2 12 bits, Main 4:4:4 8 bits, Main 4:4:4 10 bits, Main 4:4:4 12 bits, Monochrome 10 and 16 bits, a 16 bits All Intra profile with 4:4:4 and a Sill Picture 4:4:4 16 bits profile.
The 4:4:4 profiles have all the existing tools existing on the previous working draft with the exception of Intra Block Copy that was considered too complex to be included on these profiles but strongly considered for future profiles. The new techniques included are: Implicit RDPCM, Explicit RDPCM, Residual Rotation, Single ctx for Transform Skip, Rice Parameter Adaptation, Cross Component Decorrelation, and CU chroma QP offset.
JCT-VC evaluated the responses to the Call for Proposals (CfP) in relation to techniques specially designed for screen content material that will be part of new profiles in the future. The responses were considered very encouraging and offering substantial compression efficiency gains for this type of content compared with the new profiles finalized at this meeting. JCT-VC initiated work on the coding of Screen Content with the goal of delivering a new standard for efficient encoding of Screen and Mixed Content video that are envisioned to reach FDAM (Final Draft) stage in October 2015.
Further work was conducted on the text for the future scalable profiles based on HEVC (SHVC). It is the intention to reach the FDAM stage at the next meeting in July 2014. This will be suitable for applications that required scalability (resolution, frame rate, quality, color gamut, bit dept, hybrid, interlace to progressive, etc). Most of the work on this project was on high level syntax clean ups, we had some good work on color gamut and bit-depth scalability adding some tools for this type of scalability that offers substantial gains in compression efficiency compared with Simulcast, we adopted some new techniques to perform Color Gamut Scalability efficiently based a LUT approach and some further additional work will be done in this area before the next meeting to improve even further. Final work was performed on a Hybrid approach, the base layer could be AVC/H.264 and the enhancement will be based on HEVC. More work needs to be done on this area, but it could be part of the first version of the SHVC profiles.
The result of the verification test for HEVC Version 1 were presented and they were showing that HEVC have more than 50% gains compared with AVC/H.264 when doing a subjective evaluation, these are very positive results and they do shown that with a good HEVC encoder it is possible to achieve very large gains compared with AVC/H.264 encoders.
The results of a performance evaluation done by JPEG and JCT-VC of the HEVC Still picture profile were presented and it was shown that the gains compared with JPEG 2000 are in the range of 15% better PSNR for 4:4:4 RGB, 14-26% for 4:2:0 YCC and 3-16% for 4:4:4 YCC, those results were be even better visually.
MPEG continued the work on a royalty free video standards. MPEG decided to move to Final Draft of International Standard on WebVC the format based on based on AVC/H.264 CBP. It continued working on the Video Coding for Browsers, based on the previous work done by Google on VP8, it was decided to achieve Committee Draft at this meeting.
There were some further study of adding some additional interlaced video coding tools to HEVC, after the extensive study conducted inside MPEG it was concluded that the current version of HEVC is suitable for the efficient coding of interlaced content with substantial gains compared with H.264/AVC. There will be no further interlaced coding activities inside MPEG or JCT-VC after this meeting.
Further work was conducted in relation to the support of HDR and the XYZ colour space in HEVC.
There were a number of 3D/multiview related activities, including AVC+depth, MVC+depth, Multiview HEVC, those were worked on by JCT-3V and concluding some of this standards at the next meeting in Sapporo.