by Larry Jordan
Recently, James Duke was experimenting with 10-bit (HDR) video in both Final Cut Pro X (10.4.2) and QuickTime Player and found some strange behaviors. So, he sent me several questions about how Apple is handling HDR material. After doing some homework, I discovered there is no simple answer, but these answers are important if you are working with HDR.
Currently QuickTime Player plays ProRes as 8-bit.
2. Does QuickTime Player v10.4 in High Sierra play 4K 10-bit H.265 (both Rec. 709 and Rec. 2020 PQ) video as 10-bit or 8-bit?
On certain hardware, like current generation iMacs and iMac Pros, HEVC will play back as 10-bit.
3. In a Wide Gamut HDR – Rec. 2020 PQ 4K project on iMac (Retina 5K, 27-inch, Late 2015), does FCPX 10.4.2 clip viewer brightness on the iMac display to 100 nits, even though the iMac display has > 300 nits?
The iMac display is 500 nits, which is brighter than most SDR monitors. Final Cut Pro X uses the full brightness of the display when editing with HDR clips. It also uses ColorSync, which is a feature of macOS that enables apps to display images on different Macs with consistent color and brightness.
When working with high luminance HDR images, you may wish to display the raw values for images in the Final Cut Pro viewer. That preference can be enabled in the Preferences panel, within the Playback tab (the option reads: “Show HDR as raw values”). This option displays HDR footage in the Final Cut Pro viewer without clipping highlights, so the editor can see the full image while editing.
You can read the rest of Larry’s commentary here.