FFmpeg command in mediamtx.yml works with FFmpeg streaming, but not with the "add path configuration" API

[Lil-OG]

Which version are you using?

MediaMTX v1.11.3

Which operating system are you using?

Linux amd64 Docker

Describe how to replicate the issue

1. start the server
2. publish with "ffmpeg -i udp://<10.0.0.1> -c: v copy -f rtsp rtsp:10.0.0.1/cam1 (Using the API - /v3/config/paths/add/)
3. read with VLC

Server logs

INF [WebRTC] [session ecd4e4f8] created by 172.99.2.5:56342
DEB [WebRTC] [conn 172.99.2.5:56342] [s->c] HTTP/1.1 404 Not Found
Access-Control-Allow-Credentials: true
Access-Control-Allow-Origin: *
Content-Type: application/json; charset=utf-8
Server: mediamtx

(body of 87 bytes)
INF [WebRTC] [session ecd4e4f8] closed: no one is publishing to path '75603a372e33312e363032'

Network dump

No response

[Lil-OG]

When I use the "runOnDemand" (also happens with "runOnInit") option in the mediamtx.yml, the ffmpeg command works, and I can watch my stream (via ffmpeg and my custom player). However, when I try to use the add path configuration (/v3/config/paths/add/75603a372e33312e363032) with "runOnDemand" using the EXACT same command, I get 200 but the path is added with "ready": false and "source": null (in contrast to the FFmpeg command in YML)

Here is my configuration for BOTH the yml and my API:

source: publisher
runOnDemand: ffmpeg -i udp://10.1.1.30:5002 -c:v copy -f rtsp rtsp://10.1.1.30:8554/75603a372e33312e363032
runOnDemandRestart: yes

However, after using the API, the item in the paths appears as follows:

{
    "name": "75603a372e33312e363032",
    "confName": "75603a372e33312e363032",
    "source": null,
    "ready": false,
    "readyTime": null,
    "tracks": [],
    "bytesReceived": 0,
    "bytesSent": 0,
    "readers": []
}

The "working" path item with FFmpeg command via the YML file looks like this:

{
           "name": "75603a372e33312e363032",
           "confName": "75603a372e33312e363032",
           "source": {
               "type": "rtspSession",
               "id": "e6a232df-52dc-45f2-b5c8-e7d03127275d"
           },
           "ready": true,
           "readyTime": "2025-04-02T15:43:51.372323572+03:00",
           "tracks": [
               "H264"
           ],
           "bytesReceived": 5145960,
           "bytesSent": 760264,
           "readers": []
}