JVET-W0152 AHG3: Overview of CTC documents and possible merging [K. Sühring, F. Bossen, X. Li, V. Seregin, K. Sharman, A. Tourapis]
The following CTC-related documents exist for VVC and HEVC:
Area of interest | HEVC | VVC | Alignment | |
SDR video | Yes (except for RA GOP, additional 8-bit profile in HEVC) | |||
High bit depth / rate | JVET-U1100 (RExt-HBD) | No | ||
Lossless, near-lossless, mixed | JVET-U1100 (RExt-HBD lossless) | No | ||
Non-4:2:0 colour formats | JVET-U1100 (RExt) | No | ||
HDR/WCG video | JCTVC-Z1020 | No, but some similarities | ||
Screen content | JCTVC-Z1015 | No, but some similarities | ||
360° video | - | |||
Scalable video coding | JCTVC-X1009 | - | ||
Reference picture resampling | (not supported) | - | ||
Neural network | - | JVET-Q2016 (new JVET work topic) | - | |
Enhanced compression tool testing | - | JVET-Q2017 (new JVET work topic) | - | |
For alignment of experiments and reduction of number of documents to maintain, it is suggested to keep only one CTC document per area of interest. Settings specific to each standard should be described in different sections of that document.
If CTC documents exist for VVC and HEVC in the same area, and the conditions are not aligned, it is suggested to keep the VVC related coding conditions and to produce comparable settings for HEVC, so that comparing these settings is possible.
If a CTC document exists in an area only for one of the standards, it was suggested to keep this document, unless there is a need to create a comparison between the standards, or exploration in the context of a newer standard. If it becomes necessary, the CTC should be updated according to the rules above.
Area of interest | HEVC | VVC | Suggested action |
SDR video | Use VVC CTC, create HEVC specific section | ||
High bit depth / rate | JVET-U1100 (RExt-HBD) | Use VVC CTC, create HEVC specific section | |
Lossless, near-lossless, mixed | JVET-U1100 (RExt-HBD lossless) | Use VVC CTC, create HEVC specific section | |
Non-4:20 colour formats | JVET-U1100 (RExt) | Use VVC CTC, create HEVC specific section | |
HDR/WCG video | JCTVC-Z1020 | Use VVC CTC, create HEVC specific section | |
Screen content | JCTVC-Z1015 | Use VVC CTC, create HEVC specific section | |
360° video | Keep | ||
Scalable video coding | JCTVC-X1009 | Update for VVC when needed | |
Reference picture resampling | (not supported) | Keep |
One expert pointed out that there is some problem when computing the HDR-specific metrics internally in VTM, or externally using HDRtools based on decoded vs. original YUV.
Another expert explained that there was some issue in VTM11, which should be resolved now (only a minor difference in third decimal point).
For HM (also in CE/EE) it is run externally.
It was agreed that there is no urgency of doing this; the AHG should plan to propose integrated version(s) of CTC document(s) as input to the next meeting.
Verification testing (5)
Contributions in this area were discussed in session 14 at 2110–2150 UTC on Monday 12 July 2021 (chaired by JRO).