Originally Posted by Dennis Frie
As far as I know Eagletree hides the information in the first couple of video-lines that's not actually used for video. But I'm not quite sure what hardware they use.
It can be done with the DIY OSD-project in this thread, as you have complete control with pixels, timing etc.
But it haven't been done yet.
I always assumed they are just using closed captioning standards, for NTSC it stores the data in line 21. I'm not sure about PAL. Obviously the throughput is very low, but I would think it would be enough to get down lat/lon/alt at 0.5 - 1 Hz.