Issue with zoneminder camera
I'm using homebridge-camera-ui a long time with my foscam 9805W directly configured without issue. I'm using motion detection with mqtt and telegram snapshot messaging. Currently only one camera is configured.
My environment is a raspberry pi 4B with all recent updates (buster, homebridge, and camera-ui - version 4.2.7)
Now I tried to configure homebridge-camera-ui to use my zoneminder instance as camera source, because the picture is faster available.

Behavior: In Apple Home app I can see the snapshot of the camera, but if the mqtt motion trigger signal comes, an error is thrown and the processing stopps.
I would expect that the snapshot is stored and the telegram message is send like my old configuration.

Configuration:
             {
                    "name": "Einfahrt ZM",
                    "videoConfig": {
                        "source": "-re -i http://pi4b-2.fritz.box:81/zm/cgi-bin/nph-zms?mode=jpeg&monitor=1&scale=100&maxfps=15&buffer=1000&user=xxxxx&pass=xxxxxxx",
                        "stillImageSource": "-i http://pi4b-2.fritz.box:81/zm/cgi-bin/nph-zms?mode=single&monitor=1&scale=100&maxfps=5&buffer=1000&user=xxxxx&pass=xxxxxxx",
                        "maxStreams": 2,
                        "maxWidth": 1280,
                        "maxHeight": 720,
                        "maxFPS": 15,
                        "debug": true
                    },
                    "mqtt": {
                        "motionTopic": "homebridge/blau/reed",
                        "motionMessage": "auf",
                        "motionResetTopic": "homebridge/blau/reed",
                        "motionResetMessage": "zu"
                    }
                }

**Logs**
during startup:
[19.8.2021, 09:07:27] [CameraUI] [Plugin] Einfahrt ZM: Starting video stream: 1280x720, 15 fps, 802 kbps
[19.8.2021, 09:07:27] [CameraUI] [Plugin] Einfahrt ZM: [fatal] Option stimeout not found.
[19.8.2021, 09:07:27] [CameraUI] [Plugin] Einfahrt ZM: ffmpeg exited with code: 1 and signal: null (Error)
[19.8.2021, 09:07:27] [CameraUI] [Plugin] Einfahrt ZM: Stopped video stream.

motion trigger:
[19.8.2021, 09:08:07] [CameraUI] [Interface] Einfahrt ZM: An error occured during handling motion event
[19.8.2021, 09:08:07] [CameraUI] Error: Image Buffer is empty!
    at ChildProcess.<anonymous> (/usr/local/lib/node_modules/homebridge-camera-ui/server/services/ffmpeg.service.js:86:29)
    at ChildProcess.emit (events.js:400:28)
    at maybeClose (internal/child_process.js:1055:16)
    at Socket.<anonymous> (internal/child_process.js:441:11)
    at Socket.emit (events.js:400:28)
    at Pipe.<anonymous> (net.js:675:12)


I guess that is is an configuration issue, do you have an idea?

thank you
André


**Environment**
- Node.js Version: v14.17.5
- Homebridge Version: v1.3.4
- Camera UI Version: v4.2.7
- Operating System: raspian buster
- Browser: chrome (PC and ipad)
- Zoneminder: 1.34.22
