[FFmpeg-user] Capture Webcam and also display on screen.

[kevin]

I need to capture webcam and also save that file/stream simultaneously in
OS X.
This command is available,

      ffmpeg -f avfoundation -i "<screen device index>:<audio device
index>" out.avi

but how to display on screen the video stream that is getting captured to
out.avi?
Thank you.