/// <summary>
/// Set the video capabilities.
/// </summary>
/// <param name="bldr">Specifies the capture builder</param>
/// <param name="flt">Specifies the video filter.</param>
/// <param name="vidCap">Specifies the desired capabilities.</param>
/// <returns><i>true</i> is returned if set, otherwise <i>false</i>.</returns>
/// <remarks>
/// @see http://blog.dvdbuilder.com/setting-video-capture-format-directshow-net
/// </remarks>
private bool setVideoCapabilities(ICaptureGraphBuilder2 bldr, IBaseFilter flt, VideoCapability vidCap)
{
int hr;
Guid cat = PinCategory.Capture;
Guid type = MediaType.Interleaved;
Guid iid = typeof(IAMStreamConfig).GUID;
object comObj = null;
IntPtr pSC = IntPtr.Zero;
AMMediaType mt = null;
try
{
hr = bldr.FindInterface(ref cat, ref type, flt, ref iid, out comObj);
if (hr != 0)
{
type = MediaType.Video;
hr = bldr.FindInterface(ref cat, ref type, flt, ref iid, out comObj);
}
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
IAMStreamConfig cfg = comObj as IAMStreamConfig;
int nCount;
int nSize;
hr = cfg.GetNumberOfCapabilities(out nCount, out nSize);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
VideoInfoHeader vih = new VideoInfoHeader();
VideoStreamConfigCaps vsc = new VideoStreamConfigCaps();
pSC = Marshal.AllocCoTaskMem(nSize);
for (int i = 0; i < nCount; i++)
{
mt = null;
IntPtr pMT;
hr = cfg.GetStreamCaps(i, out pMT, pSC);
if (hr == 0)
{
mt = Marshal.PtrToStructure <AMMediaType>(pMT);
Marshal.PtrToStructure(mt.formatPtr, vih);
Marshal.PtrToStructure(pSC, vsc);
int nMinFps = (int)(10000000 / vsc.MaxFrameInterval);
int nMaxFps = (int)(10000000 / vsc.MinFrameInterval);
if ((vih.BmiHeader.Width == vidCap.Width || vidCap.Width == 0) &&
(vih.BmiHeader.Height == vidCap.Height || vidCap.Height == 0) &&
((nMinFps <= vidCap.TargetFPS && nMaxFps >= vidCap.TargetFPS) || vidCap.TargetFPS == 0))
{
break;
}
}
if (mt != null)
{
Marshal.FreeCoTaskMem(mt.formatPtr);
mt = null;
}
}
if (mt == null)
{
return(false);
}
cfg.SetFormat(mt);
}
catch (Exception excpt)
{
return(false);
}
finally
{
if (comObj != null)
{
Marshal.ReleaseComObject(comObj);
}
if (pSC != IntPtr.Zero)
{
Marshal.FreeCoTaskMem(pSC);
}
if (mt != null)
{
Marshal.FreeCoTaskMem(mt.formatPtr);
}
}
return(true);
}
/// <summary>
/// Open a new video feed (either web-cam or video file).
/// </summary>
/// <param name="filter">Specifies the web-cam filter to use, or <i>null</i> when opening a video file.</param>
/// <param name="pb">Specifies the output window, or <i>null</i> when running headless and only receiving snapshots.</param>
/// <param name="strFile">Specifies the video file to use, or <i>null</i> when opening a web-cam feed.</param>
/// <param name="vidCap">Optionally specifies the video capabilities to use, or <i>null</i> to ignore and use the default video capabilities.</param>
/// <returns>The duration (if any) is returned, or 0.</returns>
/// <remarks>To get the video capabilities see the GetVideoCapatiblities method.</remarks>
public long Open(Filter filter, PictureBox pb, string strFile, VideoCapability vidCap = null)
{
int hr;
if (filter != null && strFile != null)
{
throw new ArgumentException("Both the filter and file are non NULL - only one of these can be used at a time; The filter is used with the web-cam and the file is used with a video file.");
}
m_selectedFilter = filter;
m_graphBuilder = (IFilterGraph2)Activator.CreateInstance(Type.GetTypeFromCLSID(Clsid.FilterGraph, true));
// When using a web-cam, create the moniker for the filter and add the filter to the graph.
if (strFile == null)
{
IMoniker moniker = m_selectedFilter.CreateMoniker();
m_graphBuilder.AddSourceFilterForMoniker(moniker, null, m_selectedFilter.Name, out m_camFilter);
Marshal.ReleaseComObject(moniker);
m_camControl = m_camFilter as IAMCameraControl;
// Create the capture builder used to build the web-cam filter graph.
m_captureGraphBuilder = (ICaptureGraphBuilder2)Activator.CreateInstance(Type.GetTypeFromCLSID(Clsid.CaptureGraphBuilder2, true));
hr = m_captureGraphBuilder.SetFiltergraph(m_graphBuilder as IGraphBuilder);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// Add the web-cam filter to the graph.
hr = m_graphBuilder.AddFilter(m_camFilter, m_selectedFilter.Name);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// Set the desired video capabilities.
if (vidCap != null)
{
setVideoCapabilities(m_captureGraphBuilder, m_camFilter, vidCap);
}
}
else
{
// Build the graph with the video file.
hr = m_graphBuilder.RenderFile(strFile, null);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
m_mediaSeek = m_graphBuilder as IMediaSeeking;
if (pb != null)
{
m_videoFrameStep = m_graphBuilder as IVideoFrameStep;
}
}
// Create the sample grabber used to get snapshots.
m_sampleGrabber = (ISampleGrabber)Activator.CreateInstance(Type.GetTypeFromCLSID(Clsid.SampleGrabber, true));
m_baseGrabFilter = m_sampleGrabber as IBaseFilter;
m_mediaControl = m_graphBuilder as IMediaControl;
// When using a target window, get the video window used with the target output window
if (pb != null)
{
m_mediaEventEx = m_graphBuilder as IMediaEventEx;
m_videoWindow = m_graphBuilder as IVideoWindow;
}
// Otherwise create the null renderer for no video output is needed (only snapshots).
else
{
m_nullRenderer = (IBaseFilter)Activator.CreateInstance(Type.GetTypeFromCLSID(Clsid.NullRenderer, true));
}
// Add the sample grabber to the filter graph.
hr = m_graphBuilder.AddFilter(m_baseGrabFilter, "Ds.Lib Grabber");
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// Turn off the sample grabber buffers.
hr = m_sampleGrabber.SetBufferSamples(false);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// Turn off the sample grabber one-shot.
hr = m_sampleGrabber.SetOneShot(false);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// Turn ON the sample grabber callback where video data is to be received.
hr = m_sampleGrabber.SetCallback(this, 1);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// Set the media format used by the sample grabber.
AMMediaType media = new AMMediaType();
media.majorType = MediaType.Video;
media.subType = MediaSubType.RGB24;
media.formatType = FormatType.VideoInfo;
hr = m_sampleGrabber.SetMediaType(media);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// Connect the WebCam Filters and Frame Grabber.
if (m_selectedFilter != null)
{
Guid cat;
Guid med;
cat = PinCategory.Preview;
med = MediaType.Video;
hr = m_captureGraphBuilder.RenderStream(ref cat, ref med, m_camFilter, null, null);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
cat = PinCategory.Capture;
med = MediaType.Video;
hr = m_captureGraphBuilder.RenderStream(ref cat, ref med, m_camFilter, null, m_baseGrabFilter);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
}
// Connect the Frame Grabber and (optionally the Null Renderer)
else
{
// Get the video decoder and its pins.
m_videoFilter = Utility.GetFilter(m_graphBuilder as IGraphBuilder, "Video Decoder", false);
IPin pOutput;
hr = Utility.GetPin(m_videoFilter, PinDirection.Output, out pOutput);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
IPin pInput;
hr = pOutput.ConnectedTo(out pInput);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
PinInfo pinInfo;
hr = pInput.QueryPinInfo(out pinInfo);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// Get the sample grabber pins.
IPin pGrabInput;
hr = Utility.GetPin(m_baseGrabFilter, PinDirection.Input, out pGrabInput);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
IPin pGrabOutput;
hr = Utility.GetPin(m_baseGrabFilter, PinDirection.Output, out pGrabOutput);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// Disconnect the source filter output and the input it is connected to.
hr = pOutput.Disconnect();
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
hr = pInput.Disconnect();
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// Connect the source output to the Grabber input.
hr = m_graphBuilder.Connect(pOutput, pGrabInput);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// When rendering video output, connect the Grabber output to the original downstream input that the source was connected to.
if (m_nullRenderer == null)
{
hr = m_graphBuilder.Connect(pGrabOutput, pInput);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
}
Marshal.ReleaseComObject(pOutput);
Marshal.ReleaseComObject(pInput);
Marshal.ReleaseComObject(pGrabInput);
Marshal.ReleaseComObject(pGrabOutput);
}
// Remove sound filters.
IBaseFilter soundFilter = Utility.GetFilter(m_graphBuilder as IGraphBuilder, "Audio Decoder", false);
if (soundFilter != null)
{
hr = m_graphBuilder.RemoveFilter(soundFilter);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
Marshal.ReleaseComObject(soundFilter);
}
soundFilter = Utility.GetFilter(m_graphBuilder as IGraphBuilder, "Sound", false);
if (soundFilter != null)
{
hr = m_graphBuilder.RemoveFilter(soundFilter);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
Marshal.ReleaseComObject(soundFilter);
}
// When using a headless (no video rendering) setup, connect the null renderer to the Sample Grabber.
if (m_nullRenderer != null)
{
// Add the null renderer.
hr = m_graphBuilder.AddFilter(m_nullRenderer, "Null Renderer");
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// Get the sample grabber output pin.
IPin pGrabOutput;
hr = Utility.GetPin(m_baseGrabFilter, PinDirection.Output, out pGrabOutput);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// Get the null renderer input pin.
IPin pInput;
hr = Utility.GetPin(m_nullRenderer, PinDirection.Input, out pInput);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// Disconnect the sample grabber pin.
hr = pGrabOutput.Disconnect();
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// Connect the Grabber output to the null renderer.
hr = m_graphBuilder.Connect(pGrabOutput, pInput);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
Marshal.ReleaseComObject(pInput);
Marshal.ReleaseComObject(pGrabOutput);
// Remove the Video Renderer for it is no longer needed.
IBaseFilter ivideorender = Utility.GetFilter(m_graphBuilder as IGraphBuilder, "Video Renderer");
if (ivideorender != null)
{
m_graphBuilder.RemoveFilter(ivideorender);
Marshal.ReleaseComObject(ivideorender);
}
}
// Get the sample grabber media settings and video header.
media = new AMMediaType();
hr = m_sampleGrabber.GetConnectedMediaType(media);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
if ((media.formatType != FormatType.VideoInfo &&
media.formatType != FormatType.WaveEx &&
media.formatType != FormatType.MpegVideo) ||
media.formatPtr == IntPtr.Zero)
{
throw new Exception("Media grabber format is unknown.");
}
// Get the video header with frame sizing information.
m_videoInfoHeader = Marshal.PtrToStructure(media.formatPtr, typeof(VideoInfoHeader)) as VideoInfoHeader;
Marshal.FreeCoTaskMem(media.formatPtr);
media.formatPtr = IntPtr.Zero;
// If we are rendering video output, setup the video window (which requires a message pump).
if (m_videoWindow != null)
{
// setup the video window
hr = m_videoWindow.put_Owner(pb.Handle);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
hr = m_videoWindow.put_WindowStyle(WS_CHILD | WS_CLIPCHILDREN | WS_CLIPSIBLINGS);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// resize the window
hr = m_videoWindow.SetWindowPosition(0, 0, pb.Width, pb.Height);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
hr = m_videoWindow.put_Visible(DsHlp.OATRUE);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// Subscribe to the picturebox size changed event.
pb.SizeChanged += Pb_SizeChanged;
}
// start the capturing
hr = m_mediaControl.Run();
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
// When using a video file, immediately stop at the start.
if (strFile != null)
{
hr = m_mediaControl.Pause();
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
}
// When using a media file, we need to save the video file's duration.
if (m_mediaSeek != null)
{
hr = m_mediaSeek.GetDuration(out m_lDuration);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
}
m_bConnected = true;
return(m_lDuration);
}
