Investigate how to handle wide color gamut videos without HDR metadata

[kmcclive]

As a user, I want Tricycle to support tone-mapping of videos with a wide color gamut even if they don't have HDR metadata so that I can play the videos on devices that don't support wide color gamut.

It would be good to notify the user that, while Tricycle can still transcode the video, it won't likely trigger HDR mode on most displays.