FFmpeg recording process exited with error! (null) since 5.0.12
Since 5.0.12 update I receive a lot of FFmpeg recording process exited with error! (null) for multiple cams.  My last proper recordings are from this Sunday 3 pm CET everything later was not recorded because of this error for all cams:

```
[24.1.2022, 07:17:19] [CameraUI] camera.ui v5.0.14 is listening on port 8081 (http)
[24.1.2022, 07:17:32] [CameraUI] VIDEOANALYSIS: New message: Data: [{"zone":"region0","percent":7.012152671813965,"sensitivity":94,"dwell":60,"forceClose":3}] - Motion: detected - Camera: CAM-02
[24.1.2022, 07:17:32] [CameraUI] CAM-02: Motion ON
[24.1.2022, 07:17:33] [CameraUI] CAM-02: FFmpeg recording process exited with error! (null)
[24.1.2022, 07:17:40] [CameraUI] CAM-02: Closing recording process
[HDS ::ffff:10.0.1.87] Recording download stream 1 is still awaiting generator although stream was closed 10s ago! This is a programming mistake by the camera implementation which prevents freeing up resources.
[24.1.2022, 07:17:52] [CameraUI] CAM-02: Motion OFF - Motion handler timeout.
```

My config is

```
                {
                    "name": "CAM-02",
                    "manufacturer": "Reolink",
                    "model": "RLC-810A",
                    "serialNumber": "CAM-02",
                    "motion": true,
                    "doorbell": false,
                    "switches": true,
                    "motionTimeout": 20,
                    "unbridge": true,
                    "hsv": true,
                    "prebuffering": true,
                    "forcePrebuffering": false,
                    "prebufferLength": 4,
                    "videoConfig": {
                        "source": "-i rtmp://XXX/bcs/channel0_ext.bcs?channel=0&stream=2&user=XXX&password=XXX -map 0 -an -dn -flags -global_header",
                        "subSource": "-i rtmp://XXX/bcs/channel0_ext.bcs?channel=0&stream=2&user=XXX&password=XXX -map 0 -an -dn -flags -global_header",
                        "stillImageSource": "-i http://XXX/cgi-bin/api.cgi?cmd=Snap&channel=1&rs=XXX&user=XXX&password=XXX",
                        "maxStreams": 10,
                        "maxWidth": 1280,
                        "maxHeight": 720,
                        "maxFPS": 30,
                        "forceMax": false,
                        "audio": false,
                        "debug": false,
                        "vcodec": "copy"
                    },
                    "videoanalysis": {
                        "active": true
                    },
                    "smtp": {
                        "email": "CAM-02"
                    },
                    "mqtt": {}
                }
```
