Found in the Videos section of the iOS Settings app, two Playback Quality options allow you to independently choose between “Good” (basically SD quality) or “Best Available” (full HD quality) for both Wi-Fi and Cellular data connections. Users on limited data plans will almost certainly want to stick with the “Good” setting for Cellular, at least, although if you’ve got an older device and aren’t concerned about HD quality, you can get some performance gains from using “Good” for Wi-Fi connections as well.
