https://techcrunch.com/2017/09/08/youtube-launches-hdr-playback-on-select-mobile-devices/

Last November, YouTube began supporting HDR for those who watch its videos via their TV sets. Today, the company announced it’s expanding the technology to mobile, initially on select Android devices, but not yet on iOS. With support for HDR, videos offer better picture quality, with higher contrast that allows you to see more vibrant colors and make out more of the image in darker scenes.

At launch, YouTube mobile HDR is rolling out to Pixel, LG V30, Samsung Galaxy S8 and Note8, and Sony Experia XZ Premium devices, through the YouTube mobile app.