capture.cs

一个Wince的小程序

                    {
                        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;
        }

        // Set the video window within the control specified by hControl
        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);
        }

        // Set the Framerate, and video size
        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;
            }
        }

        /// <summary> Shut down capture </summary>
        private void CloseInterfaces()
        {
            int hr;

            try
            {
                if (m_FilterGraph != null)
                {
                    IMediaControl mediaCtrl = m_FilterGraph as IMediaControl;

                    // Stop the graph
                    hr = mediaCtrl.Stop();
                }
            }
            catch (Exception ex)
            {
                Debug.WriteLine(ex);
            }

            if (m_FilterGraph != null)
            {
                Marshal.ReleaseComObject(m_FilterGraph);
                m_FilterGraph = null;
            }

            if (m_VidControl != null)
            {
                Marshal.ReleaseComObject(m_VidControl);
                m_VidControl = null;
            }

            if (m_pinStill != null)
            {
                Marshal.ReleaseComObject(m_pinStill);
                m_pinStill = null;
            }
        }

        /// <summary> sample callback, NOT USED. </summary>
        int ISampleGrabberCB.SampleCB(double SampleTime, IMediaSample pSample)
        {
            Marshal.ReleaseComObject(pSample);
            return 0;
        }

        /// <summary> buffer callback, COULD BE FROM FOREIGN THREAD. </summary>
        int ISampleGrabberCB.BufferCB(double SampleTime, IntPtr pBuffer, int BufferLen)
        {
            // Note that we depend on only being called once per call to Click.  Otherwise
            // a second call can overwrite the previous image.
            Debug.Assert(BufferLen == Math.Abs(m_stride) * m_videoHeight, "Incorrect buffer length");

            if (m_WantOne)
            {
                m_WantOne = false;
                Debug.Assert(m_ipBuffer != IntPtr.Zero, "Unitialized buffer");

                // Save the buffer
                CopyMemory(m_ipBuffer, pBuffer, BufferLen);

                // Picture is ready.
                m_PictureReady.Set();
            }

            return 0;
        }
    }
}