Channels

A channel is an established connection between two VT modules.

channel_start

Start channel/output.

JSON request example:

request
{
"type": "command",
"to": "WbaqzsMXqeQiwuoa",        // manager id
"command": {
"command": "channel_start",
"channel": "mp://mplaylist _ML_UID:{42CE8DCF-14EC-00DA-9625-91768E3ED46E}",    // channel name
"props": "mode='NDI'"          // mode - output device name (only for receiver channel)
}
}

C# code example:

public void Start(string device = null)
        {
            var message = new
            {
                type = "command",
                to = Manager.Id,
                command = new
                {
                    command = "channel_start",
                    channel = Name,
                    props = Manager.Name == "_VT_MNG_RCV_" ? $"mode='{device ?? "NDI"}'" : "",
                },
            };

            Action<SocketIOResponse> callback = (response) => Console.WriteLine($"<-- response: {response}");

            Client.Emit("request", message, callback);
        }

channel stop

Stop channel/output.

JSON request example:

request
{
"type": "command",
"to": "gBZX5HEiKGqmIMWR",        // manager id
"command": {
"command": "channel_stop",
"channel": "mp://mplaylist",   // channel name
"props": ""
}
}

C# code example:

public void Stop()
        {
            var message = new
            {
                type = "command",
                to = Manager.Id,
                command = new
                {
                    command = "channel_stop",
                    channel = Name,
                    props = "",
                },
            };

            Action<SocketIOResponse> callback = (response) => Console.WriteLine($"<-- response: {response}");

            Client.Emit("request", message, callback);
        }
message, callback);
}

channel_info_get

Get channel properties values (statistics).

JSON request example:

request
{
"type": "command",
"to": "yPj3mDK3575JB0Qb",        // manager id
"command": {
"command": "channel_info_get",
"channel": "mp://mplaylist",   // channel name
"props": [                     // props names
"type",
"video_format",
"video_fps",
"stat::status"
]
}
}

JSON callback example:

callback
[
{
"channel": "mp://mplaylist",
"channelState": 3,
"channelType": 3,
"objectName": "VT_Publisher [hpH4R3SLtsNp5NCT]",
"previewURL": "[<https://vt08.medialooks.com:8080/CDqjLuf4CFwkkeW+>]",
"props": [                     // props values
{
"type": "mp"
},
{
"video_format": "[email protected] 48.0:4ch"
},
{
"video_fps": "24.00"
},
{
"stat::status": "(Web20:0) Ready for connect VT20 GW:3 W:0 C:0 "
}
],
"type": "info"
},
null
]

C# code example:

ppublic async Task<string> GetProps(string name)
        {
            var request = new
            {
                type = "command",
                to = Manager.Id,
                command = new
                {
                    command = "channel_info_get", 
                    channel = Name,
                    props = new string[] { name },
                },
            };

            string value = null;
            Action<SocketIOResponse> callback = (response) =>
            {
                Console.WriteLine($"<-- response: {response}");

                try
                {
                    value = response.GetValue(0)
                                    .GetProperty("props")
                                    .EnumerateArray()
                                    .Select(i => i.EnumerateObject().FirstOrDefault())
                                    .First()
                                    .Value
                                    .ToString();
                }
                catch (Exception e)
                {
                    Console.WriteLine($"exception: {e.Message}");
                }
            };

            Client.Emit("request", request, callback);

            await Task.Delay(500);

            return value;
        }

channel_props_set

Set channel props values

JSON message example:

message
{
"type": "command",
"to": "yPj3mDK3575JB0Qb",        // manager id
"command": {
"command": "channel_props_set",
"channel": "mp://mplaylist",   // channel name
"props": "video_bitrate=\\"15M\\""       // props name and new value
}
}

C# code example:

public void SetProps(string name, string value)
        {
            var message = new
            {
                type = "command",
                to = Manager.Id,
                command = new
                {
                    command = "channel_props_set",
                    channel = Name,
                    props = $"{name}=\"{value}\"",
                },
            };

            Client.Emit("message", message);
        }

channel_props_remove

Remove channel props.

JSON message example:

message
{
"type": "command",
"to": "yPj3mDK3575JB0Qb",        // manager id
"command": {
"command": "channel_props_remove",
"channel": "mp://mplaylist",   // channel name
"props": [                     // props names
"test_pops"
]
}
}

C# code example:

public void RemoveProps(string name)
        {
            var message = new
            {
                type = "command",
                to = Manager.Id,
                command = new
                {
                    command = "channel_props_remove",
                    channel = Name,
                    props = new string[] { name },
                },
            };

            Client.Emit("message", message);
        }

channel_frame_get

Get a picture from the channel.

JSON request example:

request
{
"type": "command",
"to": "yPj3mDK3575JB0Qb",        // manager id
"command": {
"command": "channel_frame_get",
"channel": "mp://mplaylist",   // channel name
"maxWidth": 300,               // frame size constraints
"maxHeight": 250
}
}

JSON callback example:

callback
[
{
"binary": {
"type": "Buffer",
"data": [...]                // byte array of frame image in JPG format
},
"payload": {
"channel": "USB Video Device",
"msec_updated": "0.087000",
"objectName": "VT_Publisher [VO0Ero58L6lA8iub]",
"type": "image",
"vt_getimage_msec": "922",
"vt_time": "1653593491843"
},
"to": [],
"type": "command"
},
null
]

C# code example:

public void GetFrame()
        {
            var request = new
            {
                type = "command",
                to = Manager.Id,
                command = new
                {
                    command = "channel_frame_get",
                    channel = Name,
                    maxWidth = 300,
                    maxHeight = 250,

                },
            };

            Action<SocketIOResponse> callback = (response) =>
            {
                Console.WriteLine($"<-- response: {response}");

                try
                {
                    if (response.GetValue(0).TryGetProperty("binary", out var binary))
                    {
                        byte[] buffer = binary.GetProperty("data")
                                              .EnumerateArray()
                                              .Select(i => i.GetByte())
                                              .ToArray();

                        using var stream = new MemoryStream(buffer);
                        Application.Current.Dispatcher.Invoke(() =>
                        {
                            var window = new FrameWindow() { Owner = Application.Current.MainWindow };
                            var image = new BitmapImage();
                            image.BeginInit();
                            image.StreamSource = stream;
                            image.EndInit();
                            window.Image.Source = image;
                            window.ShowDialog();
                        }); 
                    }
                }
                catch (Exception e)
                {
                    Console.WriteLine($"exception: {e.Message}");
                }
            };

            Client.Emit("request", request, callback);
        }

webguest:control:get

Get the Web Guest settings.

JSON request example:

request
{
"type": "command",
"to": "YaQ2BMnUvaw7vzMJSI5SP",   // channel peer id from "peer:id" props value
"command": {
"type": "webguest:control:get"
}
}

JSON callback example:

callback
[
null,
{
"type": "command:response",
"command": {
"type": "webguest:control:get"
},
"response": [                  // setting collection
{
"name": "Name",            // display name (to show on UI)
"fieldName": "name",       // inner field name
"value": "Guest1178"       // value
},
{
"name": "Location",
"fieldName": "location",
"value": "Web"
},
{
"name": "Resolution",
"fieldName": "resolution",
"value": "640x480",
"options": [               // collection of possible values for selectors
{
"value": "320x240",    // value
"label": "320x240"     // label to show on UI
},
{
"value": "640x360",
"label": "640x360"
},
...
]
},
...
]
}
]

C# code example:

public async Task<string> GetWebGuestSettings()
        {
            string peerId = await GetProps("peer::id");

            var request = new
            {
                type = "command",
                to = peerId,
                command = new
                {
                    type = "webguest:control:get",
                },
            };

            string settings = null;
            Action<SocketIOResponse> callback = (response) =>
            {
                Console.WriteLine($"<-- response: {response}");

                try
                {
                    if (response.GetValue(0).GetString() == null)
                    {
                        settings = response.GetValue(1).GetProperty("response").GetRawText();
                    }
                }
                catch (Exception e)
                {
                    Console.WriteLine($"exception: {e.Message}");
                }
            };

            Client.Emit("request", request, callback);

            await Task.Delay(200);

            return settings;
        }

webguest:control:set

Set the Web Guest settings.

JSON message example

message
{
"type": "command",
"to": "YaQ2BMnUvaw7vzMJSI5SP",   // channel peer id from "peer:id" props value
"command": {                     // settings collection (see settings format in webguest:control:get)
"type": "webguest:control:set",
"settings": [
{
"name": "Name",
"fieldName": "name",
"value": "GuestTest"
},
{
"name": "Location",
"fieldName": "location",
"value": "Web"
},
{
"name": "Resolution",
"fieldName": "resolution",
"value": "640x480",
"options": [
{
"value": "320x240",
"label": "320x240"
},
{
"value": "640x360",
"label": "640x360"
},
{
"value": "640x480",
"label": "640x480"
},
...
]
},
...
]
}
}

C# code example:

public async void SetWebGuestSettings(string settings)
        {
            string peerId = await GetProps("peer::id");

            var request = new
            {
                type = "command",
                to = peerId,
                command = new
                {
                    type = "webguest:control:set",
                    settings = JsonDocument.Parse(settings),
                },
            };

            Client.Emit("message", request);
        }