Streaming on HomeKit causes camera crash (HomeBridge logs included)
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**Describe The Problem:**
Hi there, if I just leave the video on the tile it seems to work fine. But as soon as I click the tile to go into full screen it "crashes" and the video goes offline on HomeKit (it has no effect on the unifi app and is fine there). If I open it again it will load the image immediately, then freeze and crash (unless I quickly exit at which point I have the old image). This is true for all my unifi cameras (i.e. doorbell, g4 pro, and g3 flex). 

As a side note, if someone rings the doorbell, HomeKit will notify the doorbell has been rung, but soon as you try to look at it, it dies immediately.


**To Reproduce:**
Access any camera directly either by clicking on the tile for any Unifi camera or by clicking on an alert (such as the doorbell ringing).

**Logs:**
Note: I removed the MAC Addresses

```
[6/12/2021, 12:53:28 PM] [UniFi Protect] UNVR [UNVR4]: Connected to the Protect controller API (address: 10.10.10.166 mac:).
[6/12/2021, 12:53:28 PM] [UniFi Protect] UNVR [UNVR4]: Connected to the UniFi realtime update events API.
[6/12/2021, 12:53:28 PM] [UniFi Protect] UNVR [UNVR4]: Discovered camera: Driveway [UVC G4 Pro] (address: 10.10.10.92 mac:).
[6/12/2021, 12:53:28 PM] [UniFi Protect] UNVR [UNVR4]: Discovered camera: Backyard [UVC G4 Pro] (address: 10.10.10.10 mac:).
[6/12/2021, 12:53:28 PM] [UniFi Protect] UNVR [UNVR4]: Discovered camera: Side stairs [UVC G4 Pro] (address: 10.10.10.86 mac:).
[6/12/2021, 12:53:28 PM] [UniFi Protect] UNVR [UNVR4]: Discovered camera: Garage [UVC G3 Flex] (address: 10.10.10.106 mac:).
[6/12/2021, 12:53:28 PM] [UniFi Protect] UNVR [UNVR4]: Discovered camera: Doorbell [UVC G4 Doorbell] (address: 10.10.10.183 mac:).
[6/12/2021, 12:53:28 PM] [UniFi Protect] UNVR [UNVR4]: Controller refresh interval set to 10 seconds.
[6/12/2021, 12:53:28 PM] [UniFi Protect] UNVR [UNVR4] Doorbell [UVC G4 Doorbell]: Discovered doorbell message switch: LEAVE PACKAGE AT DOOR.
[6/12/2021, 12:53:28 PM] [UniFi Protect] UNVR [UNVR4] Doorbell [UVC G4 Doorbell]: Discovered doorbell message switch: DO NOT DISTURB.
[6/12/2021, 12:53:28 PM] [UniFi Protect] UNVR [UNVR4] Doorbell [UVC G4 Doorbell]: Discovered doorbell message switch: PRESS TO SUMMON DOG..
[6/12/2021, 12:53:28 PM] [UniFi Protect] UNVR [UNVR4] Doorbell [UVC G4 Doorbell]: Doorbell message set: PRESS TO SUMMON DOG..

node:99976) UnhandledPromiseRejectionWarning: Error: Command failed with ENOENT: ffmpeg -codecs
spawn ffmpeg ENOENT
at Process.ChildProcess._handle.onexit (internal/child_process.js:267:19)
at onErrorNT (internal/child_process.js:469:16)
at processTicksAndRejections (internal/process/task_queues.js:84:21)
(node:99976) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag --unhandled-rejections=strict (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 2)
(node:99976) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
```

**Homebridge Configuration:**

```json
{
    "controllers": [
        {
            "address": "10.10.10.166",
            "password": "<hidden>",
            "username": "homebridge"
        }
    ],
    "platform": "UniFi Protect"
}.
```

**Screenshots:**
<!-- If applicable, add screenshots to help explain your problem. -->
On the tile you get an image, but I don't know that it ever really updates:
![image](https://user-images.githubusercontent.com/61490462/121788420-03827380-cb82-11eb-8128-bba00ea89e29.png)

When you click the image:
![image](https://user-images.githubusercontent.com/61490462/121788513-adfa9680-cb82-11eb-80a2-d076a564ca54.png)




**Environment:**

* **Homebridge Version:**  1.3.4
* **Node Version:** 12.18.4
* **Homebridge-UniFi-Protect Plugin Version:** 4.4.0
* **UniFi Protect Version:** 1.18.1
* **UniFi Protect Controller Type:** UNVR
* **UniFi Protect Controller Firmware Version:** 1.4.9
* **Apple Device and iOS / macOS / iPadOS / tvOS Version:** <iOS 14.6 (iPhone & iPAD) & MacOS 11.4
* **Operating System and OS Version:** MacOS 10.3.16

**Note:**
My HomeBridge host is a Mac mini (late 2012) with 16gb of ram, 2.5ghz i5 and Intel HD Graphics 4000. It's running macOS High Sierra (nervous about updating it because of its age and what it may or may not do to HomeBridge).

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