I have a Samsung Galaxy J5 running 5.1.1, for about 6 days now I've had this problem where videos - both streamed and saved locally lag after the first 3-5 seconds for about 5 seconds but the sounds keeps playing, resulting in unsynced sound and video. Music still plays normally, and GIF's work as they should.
I haven't downloaded or updated any apps for a while before that time, my SD card is still far from being full, so is my device storage.
Is this a common problem with the J series or Android 5.1.1?
EDIT: Cache and temp data wipe with some cheeky developer option tweaking fixed it