I am trying to record uncropped 16:9 Rift CV1 videos through OculusMirror. Since the Rift has an almost square aspect ratio, this requires an increase in horizontal FoV in order to get the full vertical FoV of the headset in a 16:9 aspect ratio without black bars.
Sadly, OculusMirror seems to ignore the second (horizontal) value for FOVTanAngleMultiplier. It doesn't seem to allow you to extend the FoV beyond what is visible in the VR headset. Adjusting the vertical FoV value properly extends the vertical FoV but also produces a square aspect ratio with black bars.
So how can I increase the horizontal FoV further? Is there a way to increase the underlying render resolution (aspect ratio) so that enough horizontal picture information is available for OculusMirror to grab?