Video driver not installing

[Nurf]

Hi all. I've just purchased OBS to copy home videos from DVR recorder to my Apple Mac. I can't get the video to run and when I check my 'about my mac' only an audio driver is installed. I only get audio to record while video screen does not show anything even in preview mode (see photo). I can change input source to FaceTime camera which works fine but switching to video capture device gives me nothing (just audio). I tried selecting display capture and that also works so clearly the software is capturing some video input but not the capture device. Any help on this? Thanks