Trying to use ofxVideoRecorder: No video, just audio

No video is recorded when I use ofxVideoRecorder, just Audio.

The VideoGrabber’s dimensions are always (0,0), no matter what I set them to (ex: 640,480).

Stepping through the code, I see that

NSArray * devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];

in returns a list of zero devices. This causes the entire initialization for video to be skipped.

I have FFMpeg installed.

Anyone know why this is happening or how to fix it? I don’t need this particular plugin; i just need to be able to record audio and video of oF from within the app itself (i.e. no external screencap)