Homebridge can't access the live stream and is caught on a restart loop
Let me start by saying that chances are that this issue is not caused by a bug, but my inability to configure this plugin correctly - I would not be surprised if I was missing some obvious solution. I am trying to learn and any help would be highly appreciated.

**Describe the bug**
Every time i install this plugin and try to set up a camera (I am using an old `iPhone` 5s running `AirBeam` and following these instructions `https://sunoo.github.io/homebridge-camera-ffmpeg/configs/AirBeam.html`), I have noticed that HomeBridge is unable to visualise the live stream from this camera (I am able to do so by using the same URL I provided in the configuration of the plugin); this throws an error which I will include in the "Logs" chapter, below.
Additionally, every time I restart HomeBridge at this point, it will be caught in a loop where it tries to restart (so far I have only been able to break the loop by uninstalling `homebridge-camera-ui`).
Never at any point in this process will the camera.ui interface show that any camera has been added.

**To Reproduce**
This happens every time I try this out, as explained above; I will include a screenshot of my configuration process below (I did not change anything other than what you can see in the screenshots).

**Expected behavior**
I would expect the live view to be available when trying to open it from here:
![Screenshot_2022-03-15 16 20 45_T883t5](https://user-images.githubusercontent.com/83964741/158399354-07324944-2f7d-4383-83a2-c1f20e57d827.png)
Also, I would expect the camera to be added to HomeKit after the restart, but instead I am caught in the loop described above.

**Logs**
```
[3/15/2022, 3:57:49 PM] [Homebridge UI] [homebridge-camera-ui] Terminating child process...
[3/15/2022, 3:57:51 PM] [Homebridge UI] [homebridge-camera-ui] Incoming Request: /interfaceConfig
[3/15/2022, 3:57:52 PM] [Homebridge UI] [homebridge-camera-ui] Incoming Request: /cameras
[3/15/2022, 3:57:54 PM] [Homebridge UI] [homebridge-camera-ui] Incoming Request: /startStream
[3/15/2022, 3:57:54 PM] [Homebridge UI] [homebridge-camera-ui] Stream command: ffmpeg -hide_banner -loglevel error -i http://192.168.234.3/service/camera/video.mjpeg -f mpegts -vcodec mpeg1video -s 1280x720 -b:v 299k -r 20 -bf 0 -preset:v ultrafast -threads 1 -an -q 1 -max_muxing_queue_size 1024 -
[3/15/2022, 3:57:54 PM] [Homebridge UI] [homebridge-camera-ui] node:events:498
      throw er; // Unhandled 'error' event
      ^

Error: spawn ffmpeg ENOENT
    at Process.ChildProcess._handle.onexit (node:internal/child_process:283:19)
    at onErrorNT (node:internal/child_process:478:16)
    at processTicksAndRejections (node:internal/process/task_queues:83:21)
Emitted 'error' event on ChildProcess instance at:
    at Process.ChildProcess._handle.onexit (node:internal/child_process:289:12)
    at onErrorNT (node:internal/child_process:478:16)
    at processTicksAndRejections (node:internal/process/task_queues:83:21) {
  errno: -2,
  code: 'ENOENT',
  syscall: 'spawn ffmpeg',
  path: 'ffmpeg',
  spawnargs: [
    '-hide_banner',
    '-loglevel',
    'error',
    '-i',
    'http://192.168.234.3/service/camera/video.mjpeg',
    '-f',
    'mpegts',
    '-vcodec',
    'mpeg1video',
    '-s',
    '1280x720',
    '-b:v',
    '299k',
    '-r',
    20,
    '-bf',
    0,
    '-preset:v',
    'ultrafast',
    '-threads',
    '1',
    '-an',
    '-q',
    '1',
    '-max_muxing_queue_size',
    '1024',
    '-'
  ]
}
[3/15/2022, 3:57:54 PM] [Homebridge UI] [homebridge-camera-ui] Child process ended
```

**Screenshots**
![Screenshot_2022-03-15 16 21 00_kFGV8q](https://user-images.githubusercontent.com/83964741/158399520-cf83c84e-6a9d-4830-a822-dce9512e5206.png)
![Screenshot_2022-03-15 16 21 28_gY1tUE](https://user-images.githubusercontent.com/83964741/158399531-76716c82-4c16-41bb-8633-6948e027c72f.png)


**Environment**
- Node.js Version: v16.14.0
- Homebridge Version: v1.4.0
- Camera UI Version: v5.0.16
- Operating System: macOS 12.3 (on M1)
- Browser: Safari

Please let me know if i left out some important information.
