#Capture and stream a webcam To capture using the iSight camera on a Mac, or infact any other webcam connected to the Mac, we can use FFmpeg. First get a list of the devices installed.
ffmpeg -f avfoundation -list_devices true -i ""
This will list the aviable video and audio devices.
The below will capture at 30fps and the set video size to a file.
fmpeg -f avfoundation -framerate 30 -video_size 640x480 -i "0:none" out.avi