Raspberry : Device appears to be inactive. Stopping stream. after several minutes
After 1 or 2 minutes of stream, stream stop with message "Device appears to be inactive. Stopping stream."
Before that, stream works with image and audio. 
I try without audio but it's the same.
Any idea ?

**Logs:**


```
[2020-10-31 13:21:49] [Camera FFmpeg] [piCam] Video stream requested: 1280 x 720, 30 fps, 299 kbps
[2020-10-31 13:21:49] [Camera FFmpeg] [piCam] Starting video stream: 1280 x 720, 30 fps, 299 kbps
[2020-10-31 13:23:22] [Camera FFmpeg] [piCam] Device appears to be inactive. Stopping stream.
[2020-10-31 13:23:22] [Camera FFmpeg] [piCam] Stopped video stream.
[2020-10-31 13:23:22] [Camera FFmpeg] [piCam] FFmpeg exited with code: null and signal: SIGKILL (Expected)
```

**Homebridge Config:**

```json
{
            "name": "Camera FFmpeg",
            "cameras": [
                {
                    "name": "piCam",
                    "videoConfig": {
                        "source": "-f video4linux2 -i /dev/video0 -f alsa -ac 1 -i hw:2",
                        "stillImageSource": "-f video4linux2 -ss 0.9 -i /dev/video0 -vframes 1",
                        "audio": true,
                    }
                }
            ],
            "platform": "Camera-ffmpeg"
        }
```

**Environment:**

* **Node.js Version**: v12.19.0
* **NPM Version**: 6.14.8
* **Homebridge Version**: 1.1.6
* **Homebridge Camera FFmpeg Version**: 3.0.3
* **Homebridge Config UI X Plugin Version**: 4.31.0
* **Operating System**: Raspbian GNU/Linux 10 (buster)


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