IVideoCompositor Interface

Definição

Namespace:

Windows.Media.Effects

A interface que você implementa para criar um compositor de vídeo personalizado.

public interface class IVideoCompositor : IMediaExtension

/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 65536)]
/// [Windows.Foundation.Metadata.Guid(2232464446, 16908, 16911, 150, 199, 124, 152, 187, 161, 252, 85)]
struct IVideoCompositor : IMediaExtension

[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 65536)]
[Windows.Foundation.Metadata.Guid(2232464446, 16908, 16911, 150, 199, 124, 152, 187, 161, 252, 85)]
public interface IVideoCompositor : IMediaExtension

Public Interface IVideoCompositor
Implements IMediaExtension

Atributos

ContractVersionAttribute GuidAttribute

Implementações

IMediaExtension

Requisitos do Windows

Família de dispositivos	Windows 10 (introduzida na 10.0.10240.0)
API contract	Windows.Foundation.UniversalApiContract (introduzida na v1.0)

Exemplos

usando Microsoft.Graphics.Canvas; usando Microsoft.Graphics.Canvas.Effects; usando Windows.Foundation.Collections; usando Windows.Graphics.DirectX.Direct3D11; usando Windows.Media.Effects; usando Windows.Media.MediaProperties; usando o Windows.UI;

namespace Effects
{
    /// <summary>
    /// Chroma key compositor
    /// <list type="Bullet">
    /// <listheader>Properties</listheader>
    /// <item>Color (Color) : Chroma key color (default is black)</item>
    /// <item>Feather (Boolean): true to soften edges of the output (default is false)</item>
    /// <item>Tolerance (float): Color tolerance 0-1 (default is 0.1)</item>
    /// <item>InvertAlpha (Boolean): invert the alpha value (default is false)</item>
    /// </list>
    /// </summary>
    public sealed class ChromaKeyVideoCompositor : IVideoCompositor
    {
        #region Fields
        private VideoEncodingProperties _backgroundProperties;
        private CanvasDevice _canvasDevice;
        #endregion

        #region Properties
        /// <summary>
        /// Gets the chroma-key color
        /// </summary>
        public Color Color { get; private set; } = Colors.Black;

        /// <summary>
        /// Gets a value indicating whether to feather the edges of the chroma key
        /// </summary>
        public bool Feather { get; private set; } = false;

        /// <summary>
        /// Gets the color tolerance 
        /// </summary>
        public float Tolerance { get; private set; } = 0.1f;

        /// <summary>
        /// Gets a value indicating whether to invert the alpha transparency
        /// </summary>
        public bool InvertAlpha { get; private set; } = false;

        /// <summary>
        /// Gets a value indicating whether the compositor is time-independent
        /// </summary>
        public bool TimeIndependent => true;
        #endregion

        #region Methods
        /// <summary>
        /// Sets the encoding properties
        /// </summary>
        /// <param name="backgroundProperties">the background properties</param>
        /// <param name="device">the Direct3D device</param>
        public void SetEncodingProperties(VideoEncodingProperties backgroundProperties, IDirect3DDevice device)
        {
            _backgroundProperties = backgroundProperties;

            _canvasDevice = CanvasDevice.CreateFromDirect3D11Device(device);
        }

        /// <summary>
        /// Composite the frame
        /// </summary>
        /// <param name="context">the composite frame context</param>
        public void CompositeFrame(CompositeVideoFrameContext context)
        {
            foreach (var surface in context.SurfacesToOverlay)
            {
                using (CanvasBitmap inputBitmap = CanvasBitmap.CreateFromDirect3D11Surface(_canvasDevice, surface))
                using (CanvasRenderTarget renderTarget = CanvasRenderTarget.CreateFromDirect3D11Surface(_canvasDevice, context.OutputFrame.Direct3DSurface))
                using (CanvasDrawingSession ds = renderTarget.CreateDrawingSession())
                using (var chromaKeyEffect = new ChromaKeyEffect
                {
                    Source = inputBitmap,
                    Color = Color,
                    Feather = Feather,
                    Tolerance = Tolerance,
                    InvertAlpha = InvertAlpha
                })
                {
                    var overlay = context.GetOverlayForSurface(surface);

                    var destinationRectangle = overlay.Position;

                    var sourceRectangle = inputBitmap.Bounds;

                    var opacity = System.Convert.ToSingle(overlay.Opacity);

                    ds.DrawImage(chromaKeyEffect, destinationRectangle, sourceRectangle, opacity);
                }
            }
        }

        /// <summary>
        /// Close the compositor & dispose of the canvas device
        /// </summary>
        /// <param name="reason">the media effect closed reason</param>
        public void Close(MediaEffectClosedReason reason)
        {
            if (_canvasDevice != null)
            {
                _canvasDevice.Dispose();
                _canvasDevice = null;
            }
        }

        /// <summary>
        /// Discard of the queued frames
        /// </summary>
        /// <remarks>this does nothing</remarks>
        public void DiscardQueuedFrames()
        {
        }

        /// <summary>
        /// Sets the properties passed into the compositor
        /// </summary>
        /// <param name="configuration">the configuration</param>
        public void SetProperties(IPropertySet configuration)
        {
            if (configuration == null)
            {
                return;
            }

            object value;

            if (configuration.TryGetValue("Color", out value))
            {
                Color = (Color)value;
            }

            if (configuration.TryGetValue("Tolerance", out value))
            {
                Tolerance = (float)value;
            }

            if (configuration.TryGetValue("Feather", out value))
            {
                Feather = (bool)value;
            }

            if (configuration.TryGetValue("InvertAlpha", out value))
            {
                InvertAlpha = (bool)value;
            }
        }
        #endregion
    }
}

Comentários

1. Em um projeto Windows Runtime Component, derive uma classe pública lacrada dessa interface (veja o exemplo abaixo).

2. Use o nome completo da classe em um construtor MediaOverlayLayer .

   var propertySet = new PropertySet { ["Feather"] = true, ["Tolerance"] = 0,2f, ["Color"] = Colors.Blue };

   var compositorDefinition = new VideoCompositorDefinition( "Effects.ChromaKeyVideoCompositor", propertySet);

   var mediaOverlayLayer = new MediaOverlayLayer(compositorDefinition);

Propriedades

TimeIndependent

Obtém um valor que indica se o efeito de vídeo personalizado é independente de tempo.

Métodos

Close(MediaEffectClosedReason)	Chamado quando o compositor de vídeo deve fechar e limpo recursos alocados.
CompositeFrame(CompositeVideoFrameContext)	Chamado quando os quadros estão disponíveis para composição por um compositor de vídeo personalizado.
DiscardQueuedFrames()	Chamado para permitir implementações de compositor de vídeo, opcionalmente, descarte qualquer estado armazenado relacionado a quadros que já foram recebidos.
SetEncodingProperties(VideoEncodingProperties, IDirect3DDevice)	Chamado para definir as propriedades de codificação de um compositor de vídeo personalizado.
SetProperties(IPropertySet)	Define as propriedades de configuração que foram fornecidas quando o analisador de mídia ou o codec foi registrado. (Herdado de IMediaExtension)

Confira também

• IMediaExtension