I looked into it briefly for some of my cenote/cavern videos once, but came out empty handed just like you did. I've seen a really cool overlay in a video a couple of times, but every time it was different which made me suspect that they were custom jobs manually added to the video. If there is such a program or plugin for video editing software someone here ought to know about it. Good luck!
---------- Post added August 2nd, 2015 at 02:49 AM ----------
Just to add, there should be HUD-style graphical overlays available that you can add to your video, but you may have to add the numbers yourself. I would imagine designing the HUD would be most of the work (at least for me it would), so it'd be half a victory at least. As to how much work would remain after that depends on how precise you want to be (ie. depth updated every foot or every 5 feet, tank pressure every 10psi or every 10% etc.).
