macOS and HDR
The current macOS 10.13.3 Beta (17D20a) provides two .ICC HDR profiles: Rec. 709 PQ which has a narrow color space and HDR gamma. And Rec.2100 PQ which uses the much wider Rec.2020 color gamut as well as the PQ HDR gamma. PQ HDR needs metadata sent over HDMI 2.0a to be displayed correctly, yet there is no Mac (even the newest iMac Pro) that has an HDMI 2.0a port. Further there is no USB-C to HDMI 2.0a dongle available at time of publishing.
For kicks, applying the Rec.2100 PQ profile to the Built-In display of my MacBook Pro screws with everything (as it should), inverting the brightness of some windows as the screenshot shows.
I do know that a combination of the Blackmagic Decklink 4K Extreme 12G inside a Sonnet Echo Express SE I works like a charm. A cheaper work around 'may' be to use the new Sonnet eGFX Breakaway Puck that features an RX 570 for an extra 4GB of eGPU VRAM. The spec states HDMI 2.0b, which allows for both HDMI 2.0a PQ HDR metadata and HLG HDR playback. But I have yet to see anyone successfully use this product as an HDR output device.
For kicks, applying the Rec.2100 PQ profile to the Built-In display of my MacBook Pro screws with everything (as it should), inverting the brightness of some windows as the screenshot shows.
as a menu should look
with Rec.2100 PQ selected on a SDR display
I do know that a combination of the Blackmagic Decklink 4K Extreme 12G inside a Sonnet Echo Express SE I works like a charm. A cheaper work around 'may' be to use the new Sonnet eGFX Breakaway Puck that features an RX 570 for an extra 4GB of eGPU VRAM. The spec states HDMI 2.0b, which allows for both HDMI 2.0a PQ HDR metadata and HLG HDR playback. But I have yet to see anyone successfully use this product as an HDR output device.
