Audio issue since updating to iOS 15
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**Describe The Problem:**
<!-- A clear and concise description of what the bug is. -->

I have two camera using a RTSP feed with Audio ON. They always worked fine. I have updated my device (iPhone, iPad, HomePod & AppleTV to iOS 15 and since, the audio is lagging. I tried all possible configurations but I found no fixes to audio. Weird part though is that the Home App on my MacBook Air doesn't have this issue ... 

**To Reproduce:**
<!-- Steps to reproduce the behavior. --> none.

**Logs:**
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```
no relevant logs to show
```

**Homebridge Config:**

```json
"name": "Camera FFmpeg",
            "cameras": [
                {
                    "name": "Chambre",
                    "manufacturer": "D-Link",
                    "model": "DCS-8000LH",
                    "serialNumber": "SY7F3J7000897",
                    "unbridge": true,
                    "videoConfig": {
                        "source": "-i rtsp://192.168.0.165/live/profile.0",
                        "maxStreams": 4,
                        "maxWidth": 1280,
                        "maxHeight": 720,
                        "maxFPS": 30,
                        "maxBitrate": 300,
                        "forceMax": true,
                        "vcodec": "copy",
                        "packetSize": 1128,
                        "audio": true
                    }
                },
                {
                    "name": "Cuisine",
                    "manufacturer": "D-Link",
                    "model": "DCS-8000LH",
                    "serialNumber": "SY7F3J7000897",
                    "unbridge": true,
                    "videoConfig": {
                        "source": "-i rtsp://192.168.0.230/live/profile.0",
                        "maxStreams": 4,
                        "maxWidth": 1280,
                        "maxHeight": 720,
                        "maxFPS": 30,
                        "maxBitrate": 300,
                        "forceMax": true,
                        "vcodec": "copy",
                        "packetSize": 1128,
                        "audio": true
                    }
                }
            ],
            "_bridge": {
                "username": "0E:4E:FB:1B:D7:61",
                "port": 39193
            },
            "platform": "Camera-ffmpeg"
```

**Screenshots:**
<!-- If applicable, add screenshots to help explain your problem. --> none

**Environment:**

* **Node.js Version**: <!-- node -v --> v14.17.6
* **NPM Version**: <!-- npm -v --> v6.14.15
* **Homebridge Version**: <!-- homebridge -V --> v1.3.4
* **Homebridge Camera FFmpeg Version**: v3.1.3
* **Homebridge Config UI X Plugin Version**: v4.41.2
* **Operating System**: <!-- Raspbian / Ubuntu / Debian / Windows / macOS / Docker --> MacOS Mojave


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