Newbie here, but so far haven't had any problem I couldn't figure out from just reading and lurking.
Here's the one I can't figure out - I have a 3DR Quad, with the Sony FPV cam and telemetry. That works fine, plugged it into a TV and looks great. I got a Diamond One-touch video-to-USB converter, and that seems to work sort-of-ok. I tested out the video onto the HUD in Mission Planner originally just using the web-cam on my computer, all fine, as lone as I want the background to be my face!
But ever since I have installed the Diamond, although I can get the FPV video to overlay on the HUD, the roll overlay "jiggles". It's just the MP HUD, the OSD data looks smooth, and I don't think it is really something interfering with the AHRS, because if I look at the status page, the roll values don't vary any differently between when I have the video overlaid (and jiggling) or when I just have the regular PFD looking background (no jiggle).
Could be something conflicting between the two HUD displays? I haven't tried to fly with the "jiggling" happening - a little scared I'll go unstable.