Error occurred terminating FFmpeg process
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**Describe The Problem:**
<!-- A clear and concise description of what the bug is. -->
FFmpeg keeps running after stream stops chewing up CPU
**To Reproduce:**
<!-- Steps to reproduce the behavior. -->
Open a stream to Home app on mac then close it. ffmpeg continues running 
**Logs:**
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```
[8/25/2020, 2:39:33 PM] [Camera FFmpeg] [Back] Device appears to be inactive. Stopping stream.
[8/25/2020, 2:39:33 PM] [Camera FFmpeg] [Back] Error occurred terminating FFmpeg process: Error [ERR_SOCKET_DGRAM_NOT_RUNNING]: Not running
```

**Homebridge Config:**

```json
                {
                    "name": "Back",
                    "manufacturer": "Hikvision",
                    "model": "DS-2CD3132F-IW",
                    "serialNumber": "DS-2CD3132F-xxx",
                    "firmwareRevision": "V5.4.5 build 170401",
                    "videoConfig": {
                        "source": "-rtsp_transport tcp -vcodec h264_mmal -re -i rtsp://admin:frodO364@192.168.188.38/streaming/channels/2",
                        "stillImageSource": "-i http://admin:xxx@192.168.188.38/Streaming/Channels/1/picture",
                        "videoFilter": "scale=1024:576"
                    }
                },
```

**Screenshots:**
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**Environment:**

* **Node.js Version**: <!-- node -v -->v12.18.3
* **NPM Version**: <!-- npm -v -->6.14.4
* **Homebridge Version**: <!-- homebridge -V -->1.1.2
* **Homebridge Camera FFmpeg Version**:homebridge-camera-ffmpeg v3.0.0
* **Homebridge Config UI X Plugin Version**:homebridge-config-ui-x v4.26.0
* **Operating System**: <!-- Raspbian / Ubuntu / Debian / Windows / macOS / Docker --> Raspbian buster Linux pi4 5.4.51-v7l+ #1333 SMP Mon Aug 10 16:51:40 BST 2020 armv7l GNU/Linux



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