protected void createGraph()
{
Guid cat;
Guid med;
int hr;
// Ensure required properties are set
if (videoDevice == null && audioDevice == null)
{
throw new ArgumentException("The video and/or audio device have not been set. Please set one or both to valid capture devices.\n");
}
// Skip if we are already created
if ((int)graphState < (int)GraphState.Created)
{
// Garbage collect, ensure that previous filters are released
GC.Collect();
// Make a new filter graph
graphBuilder = (IGraphBuilder)Activator.CreateInstance(Type.GetTypeFromCLSID(Clsid.FilterGraph, true));
// Get the Capture Graph Builder
Guid clsid = Clsid.CaptureGraphBuilder2;
Guid riid = typeof(ICaptureGraphBuilder2).GUID;
captureGraphBuilder = (ICaptureGraphBuilder2)BugFixes.InstantiateDirectShow(ref clsid, ref riid);
// Link the CaptureGraphBuilder to the filter graph
hr = captureGraphBuilder.SetFiltergraph(graphBuilder);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// Add the graph to the Running Object Table so it can be
// viewed with GraphEdit
#if DEBUG
rotCookie = DsROT.AddGraphToRot(graphBuilder);
#endif
// Get the video device and add it to the filter graph
if (VideoDevice != null)
{
videoDeviceFilter = (IBaseFilter)Marshal.BindToMoniker(VideoDevice.MonikerString);
hr = graphBuilder.AddFilter(videoDeviceFilter, "Video Capture Device");
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
}
// Get the audio device and add it to the filter graph
if (AudioDevice != null)
{
audioDeviceFilter = (IBaseFilter)Marshal.BindToMoniker(AudioDevice.MonikerString);
hr = graphBuilder.AddFilter(audioDeviceFilter, "Audio Capture Device");
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
}
// Get the video compressor and add it to the filter graph
if (VideoCompressor != null)
{
videoCompressorFilter = (IBaseFilter)Marshal.BindToMoniker(VideoCompressor.MonikerString);
hr = graphBuilder.AddFilter(videoCompressorFilter, "Video Compressor");
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
}
// Get the audio compressor and add it to the filter graph
if (AudioCompressor != null)
{
audioCompressorFilter = (IBaseFilter)Marshal.BindToMoniker(AudioCompressor.MonikerString);
hr = graphBuilder.AddFilter(audioCompressorFilter, "Audio Compressor");
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;
cat = PinCategory.Capture;
med = MediaType.Interleaved;
Guid iid = typeof(IAMStreamConfig).GUID;
hr = captureGraphBuilder.FindInterface(
ref cat, ref med, videoDeviceFilter, ref iid, out o);
if (hr != 0)
{
// If not found, try looking for a video media type
med = MediaType.Video;
hr = captureGraphBuilder.FindInterface(
ref cat, ref med, videoDeviceFilter, ref iid, out o);
if (hr != 0)
{
o = null;
}
}
videoStreamConfig = o as IAMStreamConfig;
// Retrieve the stream control interface for the audio device
o = null;
cat = PinCategory.Capture;
med = MediaType.Audio;
iid = typeof(IAMStreamConfig).GUID;
hr = captureGraphBuilder.FindInterface(
ref cat, ref med, audioDeviceFilter, ref iid, out o);
if (hr != 0)
{
o = null;
}
audioStreamConfig = o as IAMStreamConfig;
// Retreive the media control interface (for starting/stopping graph)
mediaControl = (IMediaControl)graphBuilder;
// Reload any video crossbars
if (videoSources != null)
{
videoSources.Dispose();
}
videoSources = null;
// Reload any audio crossbars
if (audioSources != null)
{
audioSources.Dispose();
}
audioSources = null;
// Reload any property pages exposed by filters
if (propertyPages != null)
{
propertyPages.Dispose();
}
propertyPages = null;
// Reload capabilities of video device
videoCaps = null;
// Reload capabilities of video device
audioCaps = null;
// Retrieve TV Tuner if available
o = null;
cat = PinCategory.Capture;
med = MediaType.Interleaved;
iid = typeof(IAMTVTuner).GUID;
hr = captureGraphBuilder.FindInterface(
ref cat, ref med, videoDeviceFilter, ref iid, out o);
if (hr != 0)
{
med = MediaType.Video;
hr = captureGraphBuilder.FindInterface(
ref cat, ref med, videoDeviceFilter, ref iid, out o);
if (hr != 0)
{
o = null;
}
}
IAMTVTuner t = o as IAMTVTuner;
if (t != null)
{
tuner = new Tuner(t);
}
// Update the state now that we are done
graphState = GraphState.Created;
}
}
protected void destroyGraph()
{
// Derender the graph (This will stop the graph
// and release preview window. It also destroys
// half of the graph which is unnecessary but
// harmless here.) (ignore errors)
try
{
derenderGraph();
}
catch
{
}
// Update the state after derender because it
// depends on correct status. But we also want to
// update the state as early as possible in case
// of error.
graphState = GraphState.Null;
isCaptureRendered = false;
isPreviewRendered = false;
// Remove graph from the ROT
if (rotCookie != 0)
{
DsROT.RemoveGraphFromRot(ref rotCookie);
rotCookie = 0;
}
// Remove filters from the graph
// This should be unnecessary but the Nvidia WDM
// video driver cannot be used by this application
// again unless we remove it. Ideally, we should
// simply enumerate all the filters in the graph
// and remove them. (ignore errors)
if (muxFilter != null)
{
graphBuilder.RemoveFilter(muxFilter);
}
if (videoCompressorFilter != null)
{
graphBuilder.RemoveFilter(videoCompressorFilter);
}
if (audioCompressorFilter != null)
{
graphBuilder.RemoveFilter(audioCompressorFilter);
}
if (videoDeviceFilter != null)
{
graphBuilder.RemoveFilter(videoDeviceFilter);
}
if (audioDeviceFilter != null)
{
graphBuilder.RemoveFilter(audioDeviceFilter);
}
// Clean up properties
if (videoSources != null)
{
videoSources.Dispose();
}
videoSources = null;
if (audioSources != null)
{
audioSources.Dispose();
}
audioSources = null;
if (propertyPages != null)
{
propertyPages.Dispose();
}
propertyPages = null;
if (tuner != null)
{
tuner.Dispose();
}
tuner = null;
// Cleanup
if (graphBuilder != null)
{
Marshal.ReleaseComObject(graphBuilder);
}
graphBuilder = null;
if (captureGraphBuilder != null)
{
Marshal.ReleaseComObject(captureGraphBuilder);
}
captureGraphBuilder = null;
if (muxFilter != null)
{
Marshal.ReleaseComObject(muxFilter);
}
muxFilter = null;
if (fileWriterFilter != null)
{
Marshal.ReleaseComObject(fileWriterFilter);
}
fileWriterFilter = null;
if (videoDeviceFilter != null)
{
Marshal.ReleaseComObject(videoDeviceFilter);
}
videoDeviceFilter = null;
if (audioDeviceFilter != null)
{
Marshal.ReleaseComObject(audioDeviceFilter);
}
audioDeviceFilter = null;
if (videoCompressorFilter != null)
{
Marshal.ReleaseComObject(videoCompressorFilter);
}
videoCompressorFilter = null;
if (audioCompressorFilter != null)
{
Marshal.ReleaseComObject(audioCompressorFilter);
}
audioCompressorFilter = null;
// These are copies of graphBuilder
mediaControl = null;
videoWindow = null;
// For unmanaged objects we haven't released explicitly
GC.Collect();
}