Allow ffmpeg component to accept templating

I’m using the ffmpeg component, and in my configuration.yaml file, I have to specify a static “input.” I would like the “input” value to accept a template so I can specify a time range for my rtsp stream. For example, if my motion sensor detects motion, I’d like to be able to send the rtsp stream to my phone or display on the front end. The URL would look something like this: rtsp://user:password@ip:port/cam/playback?channel=3&starttime=2018_10_10_00_00_00&endtime=2018_10_10_05_00_00