I used the ffmpeg plugin "Homebridge Camera FFmpeg" with the following configuration and was able to get it to work. They've recently added some new features that I haven't implemented yet but this is good enough to get started.
"cameras": [
{
"name": "front-exterior",
"manufacturer": "Cisco Meraki",
"model": "MV72",
"motion": true,
"videoConfig": {
"source": "-rtsp_transport tcp -i rtsp://10.0.3.169:9000/live",
"stillImageSource": "-rtsp_transport tcp -i rtsp://10.0.3.169:9000/live",
"maxStreams": 2,
"maxWidth": 1280,
"maxHeight": 720,
"maxFPS": 20,
"maxBitrate": 3138,
"vcodec": "copy",
"audio": false,
"debug": false
}
},