How to show a 3D movie in Unity

Unity 2017.3 comes with awesome 360/180 stereoscopic rendering on skyboxes.

But, how can I show a standard 3D movie (SBS) on a plane?

Imagine that I am creating a cinema where I want to play a 3D movie.
I am ok with billboarding the movie screen so that it always faces the player.
I just want to see the 3D effect inside my game. Is this possible?
I tried to modify the shader for 360 stereoscopy but it is too complex for me to understand.

It’s actually pretty simple.
Just use this approach (do not worry about flipping the orientation in the shader):

For VIVE you need to setup your cameras as this: