我在 Easycap USB 2.0 上安装了 Sony Handycam，我正在使用 DirectShowLib-2005 进行图像捕捉。Capture 类的源代码如下：
public Capture(int iDeviceNum, int iWidth, int iHeight, short iBPP, Control hControl)
{
Pic_Control = hControl;
DsDevice [] capDevices;
// Get the collection of video devices
capDevices = DsDevice.GetDevicesOfCat(FilterCategory.VideoInputDevice);
if (iDeviceNum + 1 > capDevices.Length)
{
throw new Exception("No video capture devices found at that index!");
}
try
{
// Set up the capture graph
SetupGraph( capDevices[iDeviceNum], iWidth, iHeight, iBPP, hControl);
// tell the callback to ignore new images
m_PictureReady = new ManualResetEvent(false);
}
catch
{
Dispose();
throw;
}
}
private void SetupGraph(DsDevice dev, int iWidth, int iHeight, short iBPP, Control hControl)
{
int hr;
ISampleGrabber sampGrabber = null;
IBaseFilter capFilter = null;
IPin pCaptureOut = null;
IPin pSampleIn = null;
IPin pRenderIn = null;
// Get the graphbuilder object
m_FilterGraph = new FilterGraph() as IFilterGraph2;
try
{
m_rot = new DsROTEntry(m_FilterGraph);
// add the video input device
hr = m_FilterGraph.AddSourceFilterForMoniker(dev.Mon, null, dev.Name, out capFilter);
DsError.ThrowExceptionForHR( hr );
// Find the still pin
m_pinStill = DsFindPin.ByCategory(capFilter, PinCategory.Still, 0);
// Didn't find one. Is there a preview pin?
if (m_pinStill == null)
{
m_pinStill = DsFindPin.ByCategory(capFilter, PinCategory.Preview, 0);
}
// Still haven't found one. Need to put a splitter in so we have
// one stream to capture the bitmap from, and one to display. Ok, we
// don't *have* to do it that way, but we are going to anyway.
if (m_pinStill == null)
{
IPin pRaw = null;
IPin pSmart = null;
// There is no still pin
m_VidControl = null;
// Add a splitter
IBaseFilter iSmartTee = (IBaseFilter)new SmartTee();
try
{
hr = m_FilterGraph.AddFilter(iSmartTee, "SmartTee");
DsError.ThrowExceptionForHR( hr );
// Find the find the capture pin from the video device and the
// input pin for the splitter, and connnect them
pRaw = DsFindPin.ByCategory(capFilter, PinCategory.Capture, 0);
pSmart = DsFindPin.ByDirection(iSmartTee, PinDirection.Input, 0);
hr = m_FilterGraph.Connect(pRaw, pSmart);
DsError.ThrowExceptionForHR( hr );
// Now set the capture and still pins (from the splitter)
m_pinStill = DsFindPin.ByName(iSmartTee, "Preview");
pCaptureOut = DsFindPin.ByName(iSmartTee, "Capture");
// If any of the default config items are set, perform the config
// on the actual video device (rather than the splitter)
if (iHeight + iWidth + iBPP > 0)
{
SetConfigParms(pRaw, iWidth, iHeight, iBPP);
}
}
finally
{
if (pRaw != null)
{
Marshal.ReleaseComObject(pRaw);
}
if (pRaw != pSmart)
{
Marshal.ReleaseComObject(pSmart);
}
if (pRaw != iSmartTee)
{
Marshal.ReleaseComObject(iSmartTee);
}
}
}
else
{
// Get a control pointer (used in Click())
m_VidControl = capFilter as IAMVideoControl;
pCaptureOut = DsFindPin.ByCategory(capFilter, PinCategory.Capture, 0);
// If any of the default config items are set
if (iHeight + iWidth + iBPP > 0)
{
SetConfigParms(m_pinStill, iWidth, iHeight, iBPP);
}
}
// Get the SampleGrabber interface
sampGrabber = new SampleGrabber() as ISampleGrabber;
// Configure the sample grabber
IBaseFilter baseGrabFlt = sampGrabber as IBaseFilter;
ConfigureSampleGrabber(sampGrabber);
pSampleIn = DsFindPin.ByDirection(baseGrabFlt, PinDirection.Input, 0);
// Get the default video renderer
IBaseFilter pRenderer = new VideoRendererDefault() as IBaseFilter;
hr = m_FilterGraph.AddFilter(pRenderer, "Renderer");
DsError.ThrowExceptionForHR( hr );
pRenderIn = DsFindPin.ByDirection(pRenderer, PinDirection.Input, 0);
// Add the sample grabber to the graph
hr = m_FilterGraph.AddFilter( baseGrabFlt, "Ds.NET Grabber" );
DsError.ThrowExceptionForHR( hr );
if (m_VidControl == null)
{
// Connect the Still pin to the sample grabber
hr = m_FilterGraph.Connect(m_pinStill, pSampleIn);
DsError.ThrowExceptionForHR( hr );
// Connect the capture pin to the renderer
hr = m_FilterGraph.Connect(pCaptureOut, pRenderIn);
DsError.ThrowExceptionForHR( hr );
}
else
{
// Connect the capture pin to the renderer
hr = m_FilterGraph.Connect(pCaptureOut, pRenderIn);
DsError.ThrowExceptionForHR( hr );
// Connect the Still pin to the sample grabber
hr = m_FilterGraph.Connect(m_pinStill, pSampleIn);
DsError.ThrowExceptionForHR( hr );
}
// Learn the video properties
SaveSizeInfo(sampGrabber);
ConfigVideoWindow(hControl);
// Start the graph
IMediaControl mediaCtrl = m_FilterGraph as IMediaControl;
hr = mediaCtrl.Run();
DsError.ThrowExceptionForHR( hr );
}
finally
{
if (sampGrabber != null)
{
Marshal.ReleaseComObject(sampGrabber);
sampGrabber = null;
}
if (pCaptureOut != null)
{
Marshal.ReleaseComObject(pCaptureOut);
pCaptureOut = null;
}
if (pRenderIn != null)
{
Marshal.ReleaseComObject(pRenderIn);
pRenderIn = null;
}
if (pSampleIn != null)
{
Marshal.ReleaseComObject(pSampleIn);
pSampleIn = null;
}
}
}
private void SaveSizeInfo(ISampleGrabber sampGrabber)
{
int hr;
// Get the media type from the SampleGrabber
AMMediaType media = new AMMediaType();
hr = sampGrabber.GetConnectedMediaType( media );
DsError.ThrowExceptionForHR( hr );
if( (media.formatType != FormatType.VideoInfo) || (media.formatPtr == IntPtr.Zero) )
{
throw new NotSupportedException( "Unknown Grabber Media Format" );
}
// Grab the size info
VideoInfoHeader videoInfoHeader = (VideoInfoHeader) Marshal.PtrToStructure( media.formatPtr, typeof(VideoInfoHeader) );
m_videoWidth = videoInfoHeader.BmiHeader.Width;
m_videoHeight = videoInfoHeader.BmiHeader.Height;
m_stride = m_videoWidth * (videoInfoHeader.BmiHeader.BitCount / 8);
DsUtils.FreeAMMediaType(media);
media = null;
}
private void ConfigVideoWindow(Control hControl)
{
int hr;
IVideoWindow ivw = m_FilterGraph as IVideoWindow;
// Set the parent
hr = ivw.put_Owner(hControl.Handle);
DsError.ThrowExceptionForHR( hr );
// Turn off captions, etc
hr = ivw.put_WindowStyle(WindowStyle.Child | WindowStyle.ClipChildren | WindowStyle.ClipSiblings);
DsError.ThrowExceptionForHR( hr );
// Yes, make it visible
hr = ivw.put_Visible( OABool.True );
DsError.ThrowExceptionForHR( hr );
// Move to upper left corner
Rectangle rc = hControl.ClientRectangle;
hr = ivw.SetWindowPosition( 0, 0, rc.Right, rc.Bottom );
DsError.ThrowExceptionForHR( hr );
}
private void ConfigureSampleGrabber(ISampleGrabber sampGrabber)
{
int hr;
AMMediaType media = new AMMediaType();
// Set the media type to Video/RBG24
media.majorType = MediaType.Video;
media.subType = MediaSubType.RGB24;
media.formatType = FormatType.VideoInfo;
hr = sampGrabber.SetMediaType( media );
DsError.ThrowExceptionForHR( hr );
DsUtils.FreeAMMediaType(media);
media = null;
// Configure the samplegrabber
hr = sampGrabber.SetCallback( this, 1 );
DsError.ThrowExceptionForHR( hr );
}
private void SetConfigParms(IPin pStill, int iWidth, int iHeight, short iBPP)
{
int hr;
AMMediaType media;
VideoInfoHeader v;
IAMStreamConfig videoStreamConfig = pStill as IAMStreamConfig;
// Get the existing format block
hr = videoStreamConfig.GetFormat(out media);
DsError.ThrowExceptionForHR(hr);
try
{
// copy out the videoinfoheader
v = new VideoInfoHeader();
Marshal.PtrToStructure( media.formatPtr, v );
// if overriding the width, set the width
if (iWidth > 0)
{
v.BmiHeader.Width = iWidth;
}
// if overriding the Height, set the Height
if (iHeight > 0)
{
v.BmiHeader.Height = iHeight;
}
// if overriding the bits per pixel
if (iBPP > 0)
{
v.BmiHeader.BitCount = iBPP;
}
// Copy the media structure back
Marshal.StructureToPtr( v, media.formatPtr, false );
// Set the new format
hr = videoStreamConfig.SetFormat( media );
DsError.ThrowExceptionForHR( hr );
}
finally
{
DsUtils.FreeAMMediaType(media);
media = null;
}
}
代码在以下行抛出异常：hr = mediaCtrl.Run();
返回的 hr 值为 -2147023729
由于此图像捕获不起作用。有人可以帮我解决这个错误吗？