@Phrehdd - my QNAP never sleeps. My problem occurs when exiting the file, whether it completes or not. Again, doesn't matter which server or method. That as if, no freezing with Vudu so you may be on to something with QNAP responding to OPPO or vice Versa.
My equipment: JVC RS-55, SI Performance 120" 1.3 gain, OPPO BDP-105, ANTHEM MRX-1120, Roomie-iPad, QNAP 469L NAS, ROKU 4, ATV, DTV HR34-500, PS3, XBOX 360. ML Source (F), Matinee (C), MotionFX (S), Motion4 (.4), (2) Depth-i subs. M/ASlim5 Rack, CalMAN 5 Enthusiast/C6 meter.