Many prefer to use 1920x1080 still for 16:9 content and zoom the projector out either manually or automatically. The Epson, Sony, Panasonic, and JVC projectors (depending on model) have automatic lens memories. The problem is that you can't do a custom resolution for 1920x812 (or 1920x810 as many use) for many projectors since the projector only accepts 1920x1080p. (Nevermind - see edit below)
With Nvidia and AMD you can do a Desktop resize which creates a resolution within a resolution. You are stilling sending 1080p, but the visible area is only 1920x812. The problem with this method is that you can't show both resolutions to JRiver. Therefore, they aren't available as options. You have do either one or the other.
The recent madVR releases takes care of this issue because you can always keep your resolution as 1920x1080, manually or automatically zoom the lens, and then the OSD in Theater View will stay within the video area. I provided instructions
here.
If you don't want to ever mess with the lens, using 1920x812 and 1444x812 works, too. There will be a reduction in brightness - especially for 16:9, since one isn't using all the pixels of the projector.
I always show any video in its original aspect ratio and never stretch or crop. For any home theater with a projector, I recommend a 2.40 aspect ratio screen.
Edit: I see now that the custom resolution on Nvidia, at least, now use 1920x1080 timings. This makes it possible to have both 1920x1080 and 1920x812.
Edit #2: I was downloading the YouTube video while posting and just watched it. I realized I misunderstood what blgentry was saying and removed my response to him.