To Reproduce:

1. Build and run the attached project on an iPad pro.
2. Play any video.
3. Observe that there are blue lines on the sides.

It's not really possible to take a screenshot for this (the blue lines at the sides disappear, the resolution is not truncated, though, scn resolution is 2732 × 2048), but I've attached a video where the lines are visible, they are way wider on device, and are visible on both sides.

https://dl.dropboxusercontent.com/u/28552779/ipad_pro_video_player.mov

Might be caused by the non standard resolution ( 2732 x 2048 )

iPad Pro: 2732/2048 = 1.333984375..
iPad mini 2: 2048/1546 = 1.3333333..

Reproduced on:

Version 5.3.0f1 (b948b362cb65)
Wed, 11 Nov 2015 13:10:57 GMT
Branch: 5.3/staging