Stream Youtube live camera via mediamtx

[tranzmatt]

Question

I want to be able to pull a live youtube stream of a traffic camera and push it to a local rtsp server to do some testing on object rec, etc. I can do this via yt-dlp and ffmpeg from the command line:

fmpeg -re -i "$(yt-dlp -g -f bestvideo https://www.youtube.com/live/mVHTqCXsZB0)"
-c:v libx264 -preset veryfast -tune zerolatency -rtsp_transport tcp
-f rtsp rtsp://my.video.server:8554/livestream_PortHuronMichiganUS

but if i try to make that an entry in mediamtx:

port_huron_michigan_usa:
runOnReady: >
ffmpeg -re -i "$(/usr/local/bin/yt-dlp -g -f bestvideo https://www.youtube.com/live/mVHTqCXsZB0)"
-c:v libx264 -preset veryfast -tune zerolatency -rtsp_transport tcp
-f rtsp rtsp://my.video.server:8554/livestream_PortHuronMichiganUS
runOnReadyRestart: yes

it completely skips over the entry, not even fail. I'm guessing it can't "shell out" to run anything? If not, is there a way around it?