This example flow shows how to use ffmpeg to grab a frame from an IP Camera's RTSP stream and also display it on a dashboard. It is based on an earlier example from nygma2004 that uses avconv (however I prefer ffmpeg).
Edit flow save directory (or mkdir /home/pi/node-red-static)
You may need to install ffmpeg, on rPi for example; sudo apt-get install ffmpeg
Video Tutorial: https://youtu.be/etYGczFJJW4
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"quotes"... I had no idea... thanks @heinzr for not only the 2nd mention of this but the reason behind them, which guided me as to where to put these "quotes" (around my camera URL within the Grab a frame commands).
I finally got this to work with my Amcrest camera, now to move onto the next task.
Really loads down my RPi3 if I leave if running (interval) for more then a few seconds... time to upgrade.