This app does create a horizontal video regardless of the orientation of the phone. Image stabilization could be better though, although it does work somewhat. I think the main benefit of this app is that you can always hold the phone vertically, which is more stable, and take horizontal video. Contrary to what some idiot reviewers have posted, the resolution goes all the way up to 1920x1080 and the volume shutter does work...just make sure its turned on in the apps settings.
rmwpg about Horizon Camera, v1.2.5