Artifacts while using google vr sdk

Hi! I'm working under 360 video player and I use last version of google vr sdk to split up rendered frame so it can be viewed with google cardboard or oculus gear. All is ok when I'm using None option at Distortion correction field of GvrViewer class (part of Google cardboard sdk). But with option images is not in correct scale. But when I set this field to "Unity" options I have this: (black area appear at one of the lenses)

May be somebody faced with that problem? Or maybe you can suggest me to use another plugin that can split video so it can be viewed with VR headsets?