/// <summary>
/// Free the nested structures and release any COM objects within an AMMediaType struct.
/// </summary>
public static void FreeAMMediaType(CoreStreaming.AmMediaType mediaType)
{
if (mediaType.formatSize != 0)
{
Marshal.FreeCoTaskMem(mediaType.formatPtr);
}
if (mediaType.unkPtr != IntPtr.Zero)
{
Marshal.Release(mediaType.unkPtr);
}
mediaType.formatSize = 0;
mediaType.formatPtr = IntPtr.Zero;
mediaType.unkPtr = IntPtr.Zero;
}
/// <summary>
/// Connects the filters of a previously created graph
/// (created by CreateGraph()). Once rendered the graph
/// is ready to be used. This method may also destroy
/// streams if we have streams we no longer want.
/// </summary>
protected void RenderGraph()
{
var didSomething = false;
// Stop the graph
MediaControl?.Stop();
// Create the graph if needed (group should already be created)
CreateGraph();
// Derender the graph if we have a capture or preview stream
// that we no longer want. We can't derender the capture and
// preview streams separately.
// Notice the second case will leave a capture stream intact
// even if we no longer want it. This allows the user that is
// not using the preview to Stop() and Start() without
// rerendering the graph.
if (!WantPreviewRendered && IsPreviewRendered)
{
DerenderGraph();
}
// Render preview stream (only if necessary)
if (WantPreviewRendered && !IsPreviewRendered)
{
//Render preview (video -> renderer)
var cat = Uuid.PinCategory.Preview;
var med = Uuid.MediaType.Video;
var hr = CaptureGraphBuilder.RenderStream(cat, med, VideoDeviceFilter, _baseGrabFlt, null);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
//Get the IVideoWindow interface
VideoWindow = (ControlStreaming.IVideoWindow)GraphBuilder;
// Set the video window to be a child of the main window
var source = PresentationSource.FromVisual(PreviewWindow) as HwndSource;
hr = VideoWindow.put_Owner(source.Handle);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
//Set video window style
hr = VideoWindow.put_WindowStyle(ControlStreaming.WindowStyle.Child | ControlStreaming.WindowStyle.ClipChildren | ControlStreaming.WindowStyle.ClipSiblings);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
//Position video window in client rect of owner window
PreviewWindow.SizeChanged += OnPreviewWindowResize;
OnPreviewWindowResize(this, null);
//Make the video window visible, now that it is properly positioned.
hr = VideoWindow.put_Visible(ControlStreaming.OABool.True);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
IsPreviewRendered = true;
didSomething = true;
var media = new CoreStreaming.AmMediaType();
hr = SampGrabber.GetConnectedMediaType(media);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
if (media.formatType != Uuid.FormatType.VideoInfo || media.formatPtr == IntPtr.Zero)
{
throw new NotSupportedException("Unknown Grabber Media Format");
}
_videoInfoHeader = (EditStreaming.VideoInfoHeader)Marshal.PtrToStructure(media.formatPtr, typeof(EditStreaming.VideoInfoHeader));
Marshal.FreeCoTaskMem(media.formatPtr);
media.formatPtr = IntPtr.Zero;
}
if (didSomething)
{
ActualGraphState = GraphState.Rendered;
}
}
/// <summary>
/// Create a new filter graph and add filters (devices, compressors, misc),
/// but leave the filters unconnected. Call RenderGraph()
/// to connect the filters.
/// </summary>
protected void CreateGraph()
{
//Skip if already created
if ((int)ActualGraphState < (int)GraphState.Created)
{
//Make a new filter graph.
GraphBuilder = (ExtendStreaming.IGraphBuilder)Activator.CreateInstance(Type.GetTypeFromCLSID(Uuid.Clsid.FilterGraph, true));
//Get the Capture Graph Builder.
var clsid = Uuid.Clsid.CaptureGraphBuilder2;
var riid = typeof(ExtendStreaming.ICaptureGraphBuilder2).GUID;
CaptureGraphBuilder = (ExtendStreaming.ICaptureGraphBuilder2)Activator.CreateInstance(Type.GetTypeFromCLSID(clsid, true));
//Link the CaptureGraphBuilder to the filter graph
var hr = CaptureGraphBuilder.SetFiltergraph(GraphBuilder);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
var comType = Type.GetTypeFromCLSID(Uuid.Clsid.SampleGrabber);
if (comType == null)
{
throw new Exception("DirectShow SampleGrabber not installed/registered!");
}
var comObj = Activator.CreateInstance(comType);
SampGrabber = (EditStreaming.ISampleGrabber)comObj; comObj = null;
_baseGrabFlt = (CoreStreaming.IBaseFilter)SampGrabber;
var media = new CoreStreaming.AmMediaType();
//Get the video device and add it to the filter graph
if (VideoDevice != null)
{
VideoDeviceFilter = (CoreStreaming.IBaseFilter)Marshal.BindToMoniker(VideoDevice.MonikerString);
hr = GraphBuilder.AddFilter(VideoDeviceFilter, "Video Capture Device");
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
media.majorType = Uuid.MediaType.Video;
media.subType = Uuid.MediaSubType.RGB32; //RGB24;
media.formatType = Uuid.FormatType.VideoInfo;
media.temporalCompression = true; //New
hr = SampGrabber.SetMediaType(media);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
hr = GraphBuilder.AddFilter(_baseGrabFlt, "Grabber");
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
}
// Retrieve the stream control interface for the video device
// FindInterface will also add any required filters
// (WDM devices in particular may need additional
// upstream filters to function).
// Try looking for an interleaved media type
object o;
var cat = Uuid.PinCategory.Capture;
var med = Uuid.MediaType.Interleaved;
var iid = typeof(ExtendStreaming.IAMStreamConfig).GUID;
hr = CaptureGraphBuilder.FindInterface(cat, med, VideoDeviceFilter, iid, out o);
if (hr != 0)
{
// If not found, try looking for a video media type
med = Uuid.MediaType.Video;
hr = CaptureGraphBuilder.FindInterface(cat, med, VideoDeviceFilter, iid, out o);
if (hr != 0)
{
o = null;
}
}
VideoStreamConfig = o as ExtendStreaming.IAMStreamConfig;
// Retrieve the media control interface (for starting/stopping graph)
MediaControl = (ControlStreaming.IMediaControl)GraphBuilder;
// Reload any video crossbars
//if (videoSources != null) videoSources.Dispose(); videoSources = null;
_videoInfoHeader = (EditStreaming.VideoInfoHeader)Marshal.PtrToStructure(media.formatPtr, typeof(EditStreaming.VideoInfoHeader));
Marshal.FreeCoTaskMem(media.formatPtr); media.formatPtr = IntPtr.Zero;
hr = SampGrabber.SetBufferSamples(false);
if (hr == 0)
{
hr = SampGrabber.SetOneShot(false);
}
if (hr == 0)
{
hr = SampGrabber.SetCallback(null, 0);
}
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
}
//Update the state now that we are done.
ActualGraphState = GraphState.Created;
}
