Getting High Dynamic Range (HDR) on your MacOS and iPhone is really complicated. TL;dr is that on your iPhone use the dedicated NetFlix and YouTube applications. On the MacOS, twiddle Safari Develop Experimental Features to turn on VP9 while on Battery and disable Video battery optimization. And yes, I don't know why any of these matter if you are connect to power but it does.
HDR on MacOS and iPhone
This is pretty cranky and apparently much of the time when I look at my videos that are definitely HDR, it works on the iPhone but not the Mac. For Safari on the iPhone as an example, I can get 720p but not HDR only. This is even though I know I uploaded a 4K HDR video, but on the YouTube application, I get the 2160p60 HDR which is correct. This is true even for late-model Macs (basically all models after 2018 support it). It also works on iPhones roughly 12 and later.
Turning on MacOS Safari HDR Support with Battery settings?!!
Well, there are two things, first, you have to enable developer mode and for some reason the battery setting matters even though you on power (and yes this will reduce battery life if playing videos, but who doesn't want HDR all the time?):
- Safari > Settings > Advanced > Show Developer Menu and click that. A Developer entry should now be in the Menu bar
- Now choose Develop > Experimental Feature. And you need to enable HDR Mode Capability and enable VP9 SW developer on battery and VP9 Decoder. The VP9 is the new codec that is required for YouTube to show HDR. Also, make sure HDR Media Capabilities is turned on. VP9 Decoder doesn't seem to exist. But this requires a restart of Safari.
- Now in System Settings > Battery > Options > Optimize Battery when playing Video and this has to be turned off. I'm not sure why this matters when you are in
It has been pretty flaky getting YouTube HDR to work on the MacOS Safari browser. The main things are that if you are running on battery, it will turn the HDR off. This does work in for everything else include Edge, Firefox, Chrome, and Brave perfectly though. Note also that it can literally take days for the HDR conversion to happen so try this with videos that have been up there for a while.
NetFlix HDR on MacOS Safari and iPhone NetFlix App
This works with NetFlix, so it depends a bit on the provider, but I couldn't get to work on my Mac. What I see is that I can get Spatial Audio and only HD output the other browsers on Chrome, Edge, Brave, and Firefox. There are many things that don't work as Machow2 explains.
On the Mac, I have this problem that every so often, the HDR setting will turn off for my external display. You have to burrow down into System Settings > Displays > _the Display_ > High Dynamic Range. The easiest way to check this is to crank up NetFlix and see what it says, the decoder ring for them is Dolby Vision, they don't use the term HDR. With Safari, I get 2160p60 with a superscript 4K (that is some notation!) and that is fine.
With the iPhone, you can't even get NetFlix to play in Safari, but the native NetFlix application does do 4K HDR so that's your limit.
YouTube HDR on MacOS Safari with Battery Fixes and iPhone App
OK, this is pretty similar on the iPhone to NetFlix, you can get YouTube HDR on the dedicated YouTube application but at least the Safari browser will play 720p non-HDR content. A lot of this I think has to do with copyright issues as the dedicated applications are more controlled. That's just a guess.
You can see what is going on by right-clicking on the video and then selecting Stats for Nerds for the working browsers you can see the Codecs are VP09 but the key entry is called Color and it should show smpte2084 (PQ) / bt2020 which is Rec.2020 (PQ) for the rest of us. In Safari it shows Color bt709 if you didn't do the magic above. So if you are wondering what is going on then try this.