I have a DVD player in my truck with dual headrest screens. I am trying to also run the video to the D2. When I split the video to the D2 input and the headrest screen, I get a flaky rolling picture on the headrest monitor. Picture is fine with just the two headrest monitors, but with even one headrest monitor and the D2 connected I get a bad picture on the headrest. I tried running the DVD output to the D2 input, then splitting the vidoe out from the D2 to the rear monitors and same thing. Bad video on the headrests. Video is always good on the D2. Do I need a video amplifier or someth