I wonder whether the contemporary mastering monitors at the time of Dolby developing the Content Mapping versions is related to the avg_pq floor being raised between specs... I'm guessing the standard mastering display was likely a BVM-X300 OLED when the CMv2.9 spec was developed, and then a BVM-HX310 LCD by the time the CMv4 spec was being developed.RESET_9999 wrote: ↑Thu Jun 29, 2023 2:10 amCMV4.0:
No idea why they completely changed the algo for avg_pq. max_pq is indeed higher but it doesn't make a big difference in reality.
raising the avg_pq floor from 2.5 to 10nits makes the low end slightly brighter but avg_pq almost has no effect when the RPU source_pq is 1000nits.
Also, I'm guessing they raised the avg_pq floor for optimized viewing on uncalibrated consumer displays since most either crush or wash out shadows.
It would be amazing if Dolby were more open about this stuff.