Issue with Xiaomi-Dafang-Hacks cameras, snapshots work, video doesn't
Not sure if this is a plugin issue or a Dafang issue, but best estimate is that it started after the 9.26.2020 Dafang update (commit 406cf52). And a non-Dafang camera still works, and there are issues viewing with VLC, so...pretty sure it's something with Dafang, but for the sake of being thorough...

**Describe The Problem:**
Cameras that were streaming video via HomeKit are no longer doing so. Snapshots still work, but streaming does not. The plugin gives warnings on receive buffer size, backwards queue inputs, non-monotonous DTS in output stream, mp3float errors on header missing. Attempts to view the livestream in the Home app time out. I am seeing the same behavior on a Dafang-Hacks Wyzecam V2 and two Wyzecam Pans, all running the 9.26.2020 firmware. All were working previously, and have now stopped streaming. A non-Dafang camera in the same Home is working properly.

I have tried using both "vcodec": "copy" and normal FFmpeg transcoding (at various resolutions), and the same issue occurs regardless.

The cameras themselves throw no errors, video through the camera web interface works properly, no errors in the camera logs as far as I can tell. Viewing camera streams via VLC, I always get audio, but sometimes not video.


**To Reproduce:**
Configure a supported camera with the latest Xiaomi-Dafang-Hacks firmware, set it up in homebridge-camera-ffmpeg, and try to get a livestream in the Home app.

**Logs:**
(apologies for the screenshot vs. actual text; the debug log made the web-based log viewer go wonky, so the best I could do was get a series of screenshots and patch them together.)

![Screen Shot 2020-09-29 at 12 59 35 PM](https://user-images.githubusercontent.com/10470394/94600213-32a4bf00-0257-11eb-9b9f-3cf0a6de3000.png)


**Homebridge Config:**

(relevant sections included)

<pre>
        {
            "platform": "Camera-ffmpeg",
            "plugin_map": {
                "plugin_name": "homebridge-camera-ffmpeg"
            },
            "name": "Camera FFmpeg",
            "cameras": [
                {
                    "name": "KitchenCam",
                    "manufacturer": "Wyze",
                    "model": "Wyzecam Pan",
                    "folder": "/home/hoobs/cameras/kitchencam",
                    "motion": true,
                    "motionTimeout": 0,
                    "videoConfig": {
                        "source": "-i rtsp://192.168.77.5:8554/unicast",
                        "stillImageSource": "-i rtsp://192.168.77.5:8554/unicast -vframes 1 -r 1",
                        "maxStreams": 2,
                        "maxWidth": 768,
                        "maxHeight": 432,
                        "maxFPS": 10,
                        "vcodec": "copy",
                        "audio": true,
                        "debug": false
                    }
                },
                {
                    "name": "DoorbellCam",
                    "manufacturer": "August Home",
                    "model": "Doorbell Cam Pro",
                    "serialNumber": "********",
                    "folder": "/home/hoobs/cameras/doorbellcam",
                    "videoConfig": {
                        "source": "-i rtsp://user:pass@192.168.77.7/live/stream",
                        "stillImageSource": "-i rtsp://user:pass@192.168.77.7/live/stream -vframes 1 -r 1",
                        "maxStreams": 2,
                        "maxWidth": 480,
                        "maxHeight": 640,
                        "maxFPS": 15,
                        "audio": true,
                        "debug": false
                    }
                },
                {
                    "name": "GateCam",
                    "manufacturer": "Wyze",
                    "model": "Wyzecam V2",
                    "folder": "/home/hoobs/cameras/gatecam",
                    "motion": true,
                    "motionTimeout": 0,
                    "videoConfig": {
                        "source": "-i rtsp://192.168.77.13:8554/unicast",
                        "stillImageSource": "-i rtsp://192.168.77.13:8554/unicast -vframes 1 -r 1",
                        "maxStreams": 2,
                        "maxWidth": 960,
                        "maxHeight": 540,
                        "maxFPS": 10,
                        "audio": true,
                        "debug": true
                    }
                },
                {
                    "name": "StudyCam",
                    "manufacturer": "Wyze",
                    "model": "Wyzecam Pan",
                    "folder": "/home/hoobs/cameras/studycam",
                    "motion": true,
                    "motionTimeout": 0,
                    "videoConfig": {
                        "source": "-i rtsp://192.168.77.12:8554/unicast",
                        "stillImageSource": "-i rtsp://192.168.77.12:8554/unicast -vframes 1 -r 1",
                        "maxStreams": 2,
                        "maxWidth": 768,
                        "maxHeight": 432,
                        "maxFPS": 10,
                        "vcodec": "copy",
                        "audio": true,
                        "debug": false
                    }
                }
            ],
            "mqtt": "127.0.0.1",
            "portmqtt": 1883,
            "usermqtt": "mqtt-user",
            "passmqtt": "mqtt-password",
            "topic": "yonder-alerts",
            "porthttp": 8089,
            "interfaceName": "eth0"
        },
        {
            "platform": "dafangMqtt",
            "plugin_map": {
                "plugin_name": "homebridge-dafang-mqtt-republish"
            },
            "name": "Dafang MQTT",
            "server": "127.0.0.1",
            "port": 1883,
            "homebridge_topic": "yonder-alerts",
            "cameras": [
                {
                    "name": "GateCam",
                    "dafang_topic": "yonder-alerts/gatecam",
                    "cooldown": 10,
                    "accessories": {
                        "recording": true,
                        "snapshot": true,
                        "reboot": true
                    }
                },
                {
                    "name": "StudyCam",
                    "dafang_topic": "yonder-alerts/studycam",
                    "cooldown": 10,
                    "accessories": {
                        "recording": true,
                        "snapshot": true,
                        "reboot": true,
                        "motorsVertical": true,
                        "motorsHorizontal": true
                    }
                },
                {
                    "name": "KitchenCam",
                    "dafang_topic": "yonder-alerts/kitchencam",
                    "cooldown": 10,
                    "accessories": {
                        "recording": true,
                        "snapshot": true,
                        "reboot": true,
                        "motorsVertical": true,
                        "motorsHorizontal": true
                    }
                }
            ]
        }
</pre>

**Environment:**

* **Node.js Version**: 12.16.3
* **NPM Version**: 6.14.4
* **Homebridge Camera FFmpeg Version**: 3.0.3
* **HOOBS Version**: 3.2.6
* **Operating System**: Raspbian 10 "buster" on RPi3B+

