Sporadically no live video in HomeApp "Wait until no one else uses the camera"
**Describe The Bug:**
Since the Zombie ffmpeg fix release, I sporadically don't get a live video in Home App but the error that I have to wait until no one else uses the camera (although no one else is watching).
Restart of Homebridge is the only way I found to resolve the issue for some time.

In the logs I can see in this case that the device was inactive. 
It looks like the stream is not released properly and at some point HomeKit thinks that too many streams are open...

**To Reproduce:**
Only a sporadic issue. I found no way to reproduce...

**Logs:**

```
[7/27/2020, 21:09:15] [Camera-ffmpeg] [Isabel] [info] frame=27797 fps= 15 q=-1.0 size=  289434kB time=00:30:55.67 bitrate=1277.7kbits/s speed=   1x    
[7/27/2020, 21:09:16] [Camera-ffmpeg] [Isabel] [info] frame=27805 fps= 15 q=-1.0 size=  289505kB time=00:30:56.21 bitrate=1277.7kbits/s speed=   1x    
[7/27/2020, 21:09:16] [Camera-ffmpeg] [Isabel] Device appears to be inactive for over 5 seconds. Stopping stream.
[7/27/2020, 21:09:16] [Camera-ffmpeg] [Isabel] Stopped video stream.
[7/27/2020, 21:09:16] [Camera-ffmpeg] [Isabel] ffmpeg exited with code: null and signal: SIGKILL (Expected)
```

**Homebridge Config:**

``` {
                    "name": "Isabel",
                    "manufacturer": "Foscam",
                    "model": "FI9902P",
                    "motion": true,
                    "doorbell": true,
                    "switches": true,
                    "videoConfig": {
                        "source": "-rtsp_transport tcp -err_detect ignore_err -i rtsp://url -tune zerolatency -preset ultrafast",
                        "stillImageSource": "-i url",
                        "maxStreams": 2,
                        "maxWidth": 1920,
                        "maxHeight": 1280,
                        "maxFPS": 25,
                        "maxBitrate": 2000,
                        "vcodec": "copy",
                        "videoFilter": "none",
                        "additionalCommandline": "-fflags +discardcorrupt+igndts",
                        "audio": false,
                        "debug": true
                    }
```

**Environment:**

* **Node.js Version**: 12.16.2
* **NPM Version**: 6.14.4
* **Homebridge Version**: 1.1.1
* **Homebridge Camera FFmpeg Version**: 2.4.0
* **Homebridge Config UI X Plugin Version**: 4.24.0
* **Operating System**: Raspbian