Amcrest IPM-721W with Raspberry Pi 4B
**Manufacturer/Model:**
Amcrest IPM-721W 

**Homebridge Config:**

```{
            "name": "Camera FFmpeg",
            "cameras": [
                {
                    "name": "XXXXXX",
                    "manufacturer": "Amcrest",
                    "model": "IPM-721W",
                    "serialNumber": "AMCXXXXXXXXXXXXXXX",
                    "firmwareRevision": "V2.420.AC00.18.R, Build Date: 2020-02-17",
                    "unbridge": true,
                    "videoConfig": {
                        "source": "-rtsp_transport tcp -i rtsp://admin:XXXXXXXX@192.168.2.XXX/cam/realmonitor?channel=1&subtype=00&authbasic=",
                        "maxStreams": 2,
                        "maxWidth": 1280,
                        "maxHeight": 720,
                        "maxFPS": 15,
                        "maxBitrate": 1024,
                        "forceMax": false,
                        "vcodec": "libx264 -preset ultrafast",
                        "packetSize": 1316,
                        "encoderOptions": "-async 1 -vsync 1",
                        "audio": true,
                        "debug": false
                    }
                }
            ],
            "platform": "Camera-ffmpeg"
        },
```

**Additional Information:**
After a LOT of trial and error I finally got this working right !
This Amcrest camera is one of the cheapest PTZ camera available. It's web ui is extremely slow but once it's setup it works fine.

*The most helpful settings:*
-  **encoderOptions** which gives the system a little leeway and not freeze frames that are a little out of sync (I think...).
- -**rtsp_transport tcp** setting which limits the transport to TCP only so the receiving end doesn't try to reorder packets received out of order with UDP.
- **vcodec** setting; "copy" or "h264_omx" don't allow -preset ultrafast. It ads some load to the processor (about 14% per stream) but I get the stream's startup delay down to less than 5 seconds. 

And with this, it runs absolutely smoothly !
