I think I found the problem (from CNET article)...
You might want to turn off this camera feature... for now
Every iPhone 12 model received modest camera updates, one of which is the ability to record HDR -- or high dynamic range -- video with Dolby Vision. All that jargon means your videos will be brighter with more accurate colors and improved contrast. Sounds awesome, right? It is. I recorded a video a few nights ago with the iPhone 12 Pro and it actually made me say "whoa." But there's a problem -- not every app or service will work with HDR video.
Developers will need to update their app(s) in order to accept HDR video, but even then, the person viewing the video will need a capable device to see the HDR difference. For Apple devices, that includes the iPhone 8 or newer, the 2020 iPad Air, second-gen iPad Pro and some Macs.
So, what can you do? Well, you have a few options:
- You can turn off HDR video by going to Settings > Camera > Record video and turn the switch next to HDR Video to the Off position.
- Going forward, all videos will be captured in standard dynamic range,
- and you won't have any issues sharing or editing it.
- Leave HDR Video turned
- on, but when you want to share the video with, say, Facebook, use the
- Photos app instead of going into the Facebook app and uploading it
- there. By using the Photos app, your iPhone will automatically convert
- the video to SDR and upload it. When you send the video to another
- iPhone user, Apple will detect if their iPhone, iPad or Mac is
- compatible with HDR Dolby Vision. If it's not, Apple will convert the
- video automatically.
- If you leave HDR Video on
- and need to edit your video, you can use Apple's iMovie app or the
- Photos app that's built into your iPhone. You can even use iMovie to
- export the video as SDR if needed.
