LVC video input

The LVCVideoInput class is used to add video sources to the LVC pipeline. The class allows you to set the video parameters and the rectangle of the video source.

You can use any block that has a video output pad. For example, you can use VirtualVideoSourceBlock to create a virtual video source or SystemVideoSourceBlock to capture video from the webcam.

Usage

When creating an LVCVideoInput object, you must specify the MediaBlock to be used as the video data source.

Sample code

Virtual video source

The sample code below shows how to create an LVCVideoInput object with a VirtualVideoSourceBlock as the video source.

var rect = new Rect(0, 0, 640, 480);

 var name = "Video source [Virtual]";
 var settings = new VirtualVideoSourceSettings();
 var info = new VideoFrameInfoX(settings.Width, settings.Height, settings.FrameRate);
 var src = new LVCVideoInput(name, _compositor, new VirtualVideoSourceBlock(settings), info, rect, true);         
if (await _compositor.Input_AddAsync(src))
{
    // added successfully
}
else
{
    src.Dispose();
}

Screen source

For Desktop platforms, we can capture the screen. The sample code below shows how to create an LVCVideoInput object with a ScreenSourceBlock as the video source.

var settings = new ScreenCaptureDX9SourceSettings();
settings.CaptureCursor = true;
settings.Monitor = 0;
settings.FrameRate = new VideoFrameRate(30);
settings.Rectangle = new Rectangle(0, 0, 1920, 1080);

var rect = new Rect(0, 0, 640, 480);
var name = $"Screen source";
var info = new VideoFrameInfoX(settings.Rectangle.Width, settings.Rectangle.Height, settings.FrameRate);
var src = new LVCVideoInput(name, _compositor, new ScreenSourceBlock(settings), info, rect, true);

if (await _compositor.Input_AddAsync(src))
{
    // added successfully
}
else
{ 
    src.Dispose(); 
}

System video source (webcam)

The sample code below shows how to create an LVCVideoInput object with a SystemVideoSourceBlock as the video source.

We use the DeviceEnumerator class to get the video source devices. The first video device will be used as the video source. The first video format of the device will be used as the video format.

VideoCaptureDeviceSourceSettings settings = null;

var device = (await DeviceEnumerator.Shared.VideoSourcesAsync())[0];
if (device != null)
{
    var formatItem = device.VideoFormats[0];
    if (formatItem != null)
    {
        settings = new VideoCaptureDeviceSourceSettings(device)
        {
            Format = formatItem.ToFormat()
        };

        settings.Format.FrameRate = dlg.FrameRate;
    }
}

if (settings == null)
{
    MessageBox.Show(this, "Unable to configure video capture device.");
    return;
}

var name = $"Camera source [{device.Name}]";
var rect = new Rect(0, 0, 1280, 720);
var videoInfo = new VideoFrameInfoX(settings.Format.Width, settings.Format.Height, settings.Format.FrameRate);
var src = new LVCVideoInput(name, _compositor, new SystemVideoSourceBlock(settings), videoInfo, rect, true);

if (await _compositor.Input_AddAsync(src))
{
    // added successfully
}
else
{
    src.Dispose();
}

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Sample application on GitHub