@sun @cell @ElDeadKennedy that's because it was broken initially in 17.4.0 . It was fixed in a later update. Then it only worked in Safari, and then fixed again. AV1 still doesn't have a software decoder on iOS so only newer devices with a hardware decoder can play them (not sure if AV1 webm works or if it's mp4 only like opus used to be (and is occasionally brought back as mp4 exclusive because Courage™️))