YouTube now supports HDR video on the Apple iPhone X
HDR video already came to the Apple iPhone X last year via Netflix. At the same time, Netflix added such support for the iPhone 8, iPhone 8 Plus and iPad Pro models. However, when it comes to Apple's iOS powered handsets, only the Super Retina OLED display on the iPhone X supports HDR. Despite what Apple posts on its website, the Apple iPhone 8 and Apple iPhone 8 displays are not enabled for HDR. Users of the latter two models will see improvements in video quality when watching HDR video, but not to the extent as those using an iPhone X will see. As for the iPad Pro, all models will support HDR video. However, it appears that YouTube has yet to add support for Apple's high-end tablets.
Finding HDR video on YouTube isn't so difficult; the video streamer does offer many such videos, and there are a few dedicated channels with plenty of HDR enabled clips to choose from.
source: MacRumors, iDB