They don't play .webm extension files I think. Not sure if it's a codec or the whole container. You have to remux to something like .mov or .mp4 generally Lots of videos downloaded online are .webm so it's especially retarded. Apple is real annoying when it comes to codecs and file extensions. For instance, ALAC is basically completely inferior to FLAC audio in compression ratios but you can't import FLACs to the music app. This is a similar story with AAC and Opus. Opus is superior but Apple invested a lot in AAC development so they lock everyone into that. I hated those iOS days, I'm glad I can just throw opus songs on my android and forget about it.