Ffmpeg record from usb
From wikinotes
Identify video source:
ffmpeg -sources
Identify ALSA (sound) sources
arecord -l # you're looking for the card# and subdevice#
# when using within ffmpeg: -f alsa -i hw:{card#},{subdevice#}
Preview the output video/audio (separately)
ffplay -s 640x480 -i /dev/video0
ffmpeg -s 640x480 -i /dev/video1 -i /dev/vbi0 test.avi
