Raspberry PICam stream not prebuffering and console output is minimal at best.
**Describe the bug**
A clear and concise description of what the bug is.

**To Reproduce**
Configure a RPI CSI Bridge camera module and set some basic defaults and go.  Get stream running okay but then have it be fairly prone to killing the stream.  Also Prebuffer randomly dies.
```json
{
  "logLevel": "info",
  "port": 8081,
  "atHomeSwitch": false,
  "options": {
    "videoProcessor": "/usr/local/lib/node_modules/homebridge-camera-ui/node_modules/ffmpeg-for-homebridge/ffmpeg"
  },
  "ssl": {
    "active": false
  },
  "http": {
    "active": false,
    "port": 7272,
    "localhttp": false
  },
  "smtp": {
    "active": false,
    "port": 2727,
    "space_replace": "+"
  },
  "ftp": {
    "active": false,
    "useFile": false,
    "port": 5050
  },
  "mqtt": {
    "active": false,
    "tls": false,
    "port": 1883
  },
  "cameras": [
    {
      "name": "PICamNVFisheye",
      "manufacturer": "Iridium",
      "model": "PICam",
      "serialNumber": "1",
      "motion": true,
      "unbridge": true,
      "hsv": true,
      "prebuffering": true,
      "prebufferLength": 4,
      "videoConfig": {
        "source": "-i /dev/video0",
        "maxWidth": 1920,
        "maxHeight": 1080,
        "vcodec": "libx264",
        "acodec": "",
        "audio": false,
        "subSource": "-i /dev/video0",
        "stillImageSource": "-i /dev/video0",
        "maxStreams": 3,
        "maxFPS": 30,
        "maxBitrate": 1000
      },
      "videoanalysis": {
        "active": false
      },
      "motionTimeout": 15,
      "smtp": {
        "email": "PICamNVFisheye"
      },
      "mqtt": {},
      "hksvConfig": {
        "maxWidth": "1920",
        "maxHeight": "1080",
        "maxFPS": "30",
        "maxBitrate": "",
        "vcodec": "libx264"
      }
    }
  ]
}
```

**Expected behavior**
Consistent streaming without error.

**Logs**
```bash
[28/09/2022, 11:36:25] [CameraUI]  WARNING  PICamNVFisheye: Can not access prebuffer stream, skipping: Error: Prebuffer process not started!
[28/09/2022, 11:36:25] [CameraUI] PICamNVFisheye: Starting video stream: 1280x720, 30 fps, 299 kbps 
[28/09/2022, 11:36:27] [CameraUI] PICamNVFisheye: Stopped video stream.
```
**Environment**
- Node.js Version: v14.20.1
- Homebridge Version: v1.5.0
- Camera UI Version: v5.0.27
- Operating System: Linux rpi1 5.15.70-v8+ #1590 SMP PREEMPT Tue Sep 27 15:59:44 BST 2022 aarch64 GNU/Linux
- Browser: Firefox
