How to apply ffmpeg -vf filter to rtsp camera stream input?

[jerblack]

I am using scrypted to restream RTSP cameras, and one of them is pointing out my front door at a bright light that I can't control. I figured out how to take a clip of the video from the camera and, using the ffmpeg drawbox filter, I created translucent boxes over the light so it's not so bright. Here's how I do that with ffmpeg:

ffmpeg -y -i input.mp4 -vf "drawbox=x=1470:y=0:w=450:h=250:[email protected]:t=fill, drawbox=x=1250:y=0:w=1000:h=450:[email protected]:t=fill, drawbox=x=1370:y=0:w=820:h=340:[email protected]:t=fill" -r 15 -c:a aac output.mp4

My question is how do I apply that same filter to the incoming RTSP stream so that when it's restreamed, the overlay is part of that stream.