On iOS smartphone, but not on iPad, when I go on certain websites, and seems to be certain news websites, a mostly black playback video “pop-up” like page comes up as if to play a video but nothing plays. It’s just black. I have pop-ups blocked. I have to manually close the window (X) in order to see or get back to the main site. I
youtube and vimeo both rendered nothing but black for me in both Brave and Safari ios15 on iphone 7 plus. For Safari there is an advanced GPU:Media option that needed to be disabled in settings and Safari now displays normally. No such setting in Brave, and all videos are black screen on youtube.