Full-screen but with no zoom

My screen is 1920x1080 but the video is considerably smaller at 1280x724 (yes, not 720). I want to play it fullscreen, so all of the normal desktop furniture is hidden, but I do *not* want the video scaled at all. I want it precisely 1280x724 in the middle of the screen with the surround all black. I can find no combination of command-line options or keypresses that achieves this. If it's relevant, and I don't think it should be for this requirement, I'm using a -vo of x11 or vdpau.