Raspberry Pi Camera not working
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**Describe The Problem:**
Raspberry Pi camera ffmpeg exit

**To Reproduce:**
Open camera from HomeKit

**Logs:**
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```
[24/01/2022, 19:46:48] [Camera FFmpeg] [piCam] Failed to fetch snapshot.
[piCam F3F6] Snapshot request handler provided empty image buffer!
[24/01/2022, 19:46:49] [Camera FFmpeg] [piCam] Failed to fetch snapshot.
[piCam F3F6] Snapshot request handler provided empty image buffer!
[24/01/2022, 19:46:50] [Camera FFmpeg] [piCam] Starting video stream: 1280 x 720, 30 fps, 299 kbps
[24/01/2022, 19:46:50] [Camera FFmpeg] [piCam] FFmpeg exited with code: 1 and signal: null (Error)
[24/01/2022, 19:46:50] [Camera FFmpeg] [piCam] Stopped video stream.
```

**Homebridge Config:**

```json
 {
            "name": "Camera FFmpeg",
            "cameras": [
                {
                    "name": "piCam",
                    "unbridge": true,
                    "videoConfig": {
                        "source": "-re -f video4linux2 -i /dev/video0",
                        "stillImageSource": "-re -f video4linux2 -ss 0.9 -i /dev/video0 -vframes 1",
                        "maxStreams": 2,
                        "maxWidth": 1920,
                        "maxHeight": 1080,
                        "maxFPS": 30,
                        "vcodec": "h264_omx"
                    }
                }
            ],
            "platform": "Camera-ffmpeg"
        }
```

**Screenshots:**
HomeKit:
![Screenshot 2022-01-24 at 19 50 28](https://user-images.githubusercontent.com/92227828/150854069-a8d61027-2d8d-4d13-aa7b-48d131644d86.png)

**Environment:**

* **Node.js Version**: 16.13.2
* **NPM Version**: 8.1.2
* **Homebridge Version**: 1.4.0
* **Homebridge Camera FFmpeg Version**: 3.1.4
* **Homebridge Config UI X Plugin Version**: 4.42.0
* **Operating System**: Raspberry Pi OS, latest


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