I shot this video with the highest quality settings on an iPhone 7 with up-to-date OS and edited it in iMovie 10.1.8. It looks great in iMovie, and when exported as an mp4 with highest resolution. But when I upload it to YouTube, it's fuzzy. I tried uploading directly from iMovie and uploading the mp4, but there's no difference. I checked my YouTube playback settings, and they're at maximum quality, and the problem happens across browsers and in the YouTube iOS app too. Can anyone suggest something I can do to fix this? Thanks!