Problems with setup on Dahua NVR device
I'm having issues with my Dahua NVR video steams cutting out, it will play for a few seconds and then freeze, after about 10 seconds few more frames and sound and so on.

I've tracked the problem to my setup, other devices (such as my android phone running an RSTP app) run smoothly...

**Homebridge Logs**
```
[06/03/2021, 17:31:12] [Camera FFmpeg] [Driveway Camera] [Snapshot] [h264 @ 0x3af49c0] 
[06/03/2021, 17:31:12] [Camera FFmpeg] [Driveway Camera] [Snapshot] error while decoding MB 146 50, bytestream -15
[06/03/2021, 17:31:14] [Camera FFmpeg] [Driveway Camera] [Snapshot] [h264 @ 0x3af49c0] error while decoding MB 57 7, bytestream -7
[06/03/2021, 17:31:15] [Camera FFmpeg] [Driveway Camera] [Snapshot] [h264 @ 0x3af49c0] 
[06/03/2021, 17:31:15] [Camera FFmpeg] [Driveway Camera] [Snapshot] error while decoding MB 98 9, bytestream -7
[Driveway Camera 3315] The image snapshot handler for the given accessory is slow to respond! See https://git.io/JtMGR for more info.
[Driveway Camera 3315] The image snapshot handler for the given accessory is slow to respond! See https://git.io/JtMGR for more info.
[06/03/2021, 17:35:04] [Camera FFmpeg] [Driveway Camera] Fetching snapshot took 6.793 seconds.
[06/03/2021, 17:35:16] [Camera FFmpeg] [Driveway Camera] [Snapshot] [h264 @ 0x38949c0] error while decoding MB 40 50, bytestream -17
[06/03/2021, 17:35:18] [Camera FFmpeg] [Driveway Camera] [Snapshot] [h264 @ 0x38949c0] error while decoding MB 157 25, bytestream -5
[Driveway Camera 3315] The image snapshot handler for the given accessory is slow to respond! See https://git.io/JtMGR for more info.
[06/03/2021, 17:35:20] [Camera FFmpeg] [Driveway Camera] [Snapshot] [h264 @ 0x3b88840] 
[06/03/2021, 17:35:20] [Camera FFmpeg] [Driveway Camera] [Snapshot] error while decoding MB 40 50, bytestream -17
[06/03/2021, 17:35:21] [Camera FFmpeg] [Driveway Camera] Fetching snapshot took 6.548 seconds.
```

**My camera config:**
```
"name": "Driveway Camera",
                    "manufacturer": "Dahua",
                    "model": "NVR2104-P-4KS2",
                    "serialNumber": "5J02D83PBWA20D2",
                    "firmwareRevision": "V2.4.1",
                    "motion": false,
                    "motionTimeout": 0,
                    "unbridge": true,
                    "videoConfig": {
                        "source": [redacted],
                        "maxStreams": 2,
                        "maxWidth": 848,
                        "maxHeight": 477,
                        "maxFPS": 14,
                        "forceMax": false,
                        "vcodec": "h264",
                        "packetSize": 376,
                        "encoderOptions": "-preset ultrafast",
                        "audio": true
                    } 
```

**Environment:**

* **Node.js Version**:  v14.16.0
* **NPM Version**: v6.14.11
* **Homebridge Version**: v1.3.2 
* **Homebridge Camera FFmpeg Version**: v3.1.2
* **Homebridge Config UI X Plugin Version**: v4.39.1
* **Operating System**: Raspbian GNU/Linux Buster (10)
* **Hardware**: Raspberry Pi 3B+


