The only difference I notice is that, if I call prepare() before play(), I will see the the process indicator and it pre-loads data in the PlayerView, besides that I can't tell the difference if I just call play() without prepare().
Also the documentation says nothing: https://exoplayer.dev/doc/reference/com/google/android/exoplayer2/SimpleExoPlayer.html
public void prepare()
Description copied from interface: Player
Prepares the player. //<- ???
Specified by:
prepare in interface Player