Recently picked up a used note 4. I was watching a YouTube video and noticed the audio and video were not in perfect sync. The same videos work properly on tab 8.4 and my iPhone. Downloaded transformers from the play store and had the same issue.
A restart fixed the issue, must have been a glitch. A disagree with you that a delay is normal. Even my weak Nokia 520 does not have this delay.Audio and video have different delays in all the equipment they pass through (including the phones). Some devices handle that better than others. (And some S4s are probably better at it tan others. We're talking about a difference between the audio delay and the video delay of a couple of microseconds here and a couple there. If all the tolerances nin your phone happen to be in the same direction, you can get half a second delay. (I have an expensive TV set in my living room, and I can still notice a lack of sync on some shows - and that's a major network running equipment I couldn't afford the tax on.) Even with a new phone, I doubt they'd replace it for an issue like that.