无法使 IAMStreamConfig.SetFormat() 与 LifeCam Studio 配合使用

Question

我是 DirectShow 的新手，正在努力向我的应用程序添加视频流。我研究了许多解决方案（TouchLess、DirectShow.net 等），最终选择了这个 Code Project 上的小项目 没有太多内容，这就是我选择它的原因；我想要一个小的代码库来使用，因为我需要快速实现此功能。

经过一整天的阅读、实验和调试，我终于让一切运行良好。有延迟，这很令人遗憾，但我可以稍后再担心。我目前遇到的问题是相机支持 1280X720 我想使用这个分辨率。然而，它似乎决心以 640x480 的分辨率进行捕捉。当我越来越深入地学习如何设置分辨率时，我终于认为我已经弄清楚了。我还在我用作基础的注释中的代码项目页面上找到了代码。

经过 6 个小时的尝试，我无法让这台相机改变其分辨率。我没有收到任何错误，并且从 SetFormat() 返回的 HRESULT 为 0，但相机不会更改分辨率。

代码太多，无法粘贴所有内容，但我想包括构建图表的部分，因为我想这就是问题所在。

这是设置图表的代码

void CameraMethods::StartCamera(int camIndex, interior_ptr<int> width, 
    interior_ptr<int> height)
{
    if (g_pGraphBuilder != NULL)
        throw gcnew ArgumentException("Graph Builder was null");

    IMoniker *pMoniker = GetMoniker(camIndex);
    pMoniker->AddRef();

    HRESULT hr = S_OK;

    // Build all the necessary interfaces to start the capture
    if (SUCCEEDED(hr))
    {
        hr = CoCreateInstance(CLSID_FilterGraph,
            NULL,
            CLSCTX_INPROC,
            IID_IGraphBuilder,
            (LPVOID*)&g_pGraphBuilder);
    }

    if (SUCCEEDED(hr))
        hr = g_pGraphBuilder->QueryInterface(IID_IMediaControl, (LPVOID*)&g_pMediaControl);

    if (SUCCEEDED(hr))
    {
        hr = CoCreateInstance(CLSID_CaptureGraphBuilder2,
            NULL,
            CLSCTX_INPROC,
            IID_ICaptureGraphBuilder2,
            (LPVOID*)&g_pCaptureGraphBuilder);
    }

    // Setup the filter graph
    if (SUCCEEDED(hr))
        hr = g_pCaptureGraphBuilder->SetFiltergraph(g_pGraphBuilder);

    // Build the camera from the moniker
    if (SUCCEEDED(hr))
        hr = pMoniker->BindToObject(NULL, NULL, IID_IBaseFilter, (LPVOID*)&g_pIBaseFilterCam);

    // Add the camera to the filter graph
    if (SUCCEEDED(hr))
        hr = g_pGraphBuilder->AddFilter(g_pIBaseFilterCam, L"WebCam");

    // Create a SampleGrabber
    if (SUCCEEDED(hr))
        hr = CoCreateInstance(CLSID_SampleGrabber, NULL, CLSCTX_INPROC_SERVER, IID_IBaseFilter, 
            (void**)&g_pIBaseFilterSampleGrabber);

    // Configure the Sample Grabber
    if (SUCCEEDED(hr))
        hr = ConfigureSampleGrabber(g_pIBaseFilterSampleGrabber);

    //  Set the resolution - I have NO idea where this should be executed
    SetCaptureFormat(camIndex, *width, *height);

    // Add Sample Grabber to the filter graph
    if (SUCCEEDED(hr))
        hr = g_pGraphBuilder->AddFilter(g_pIBaseFilterSampleGrabber, L"SampleGrabber");

    // Create the NullRender
    if (SUCCEEDED(hr))
        hr = CoCreateInstance(CLSID_NullRenderer, NULL, CLSCTX_INPROC_SERVER, IID_IBaseFilter, 
            (void**)&g_pIBaseFilterNullRenderer);

    // Add the Null Render to the filter graph
    if (SUCCEEDED(hr))
        hr = g_pGraphBuilder->AddFilter(g_pIBaseFilterNullRenderer, L"NullRenderer");

    // Configure the render stream
    if (SUCCEEDED(hr))
        hr = g_pCaptureGraphBuilder->RenderStream(&PIN_CATEGORY_CAPTURE, &MEDIATYPE_Video, 
            g_pIBaseFilterCam, g_pIBaseFilterSampleGrabber, g_pIBaseFilterNullRenderer);

    // Grab the capture width and height
    if (SUCCEEDED(hr))
    {
        ISampleGrabber* pGrabber = NULL;
        hr = g_pIBaseFilterSampleGrabber->QueryInterface(IID_ISampleGrabber, (LPVOID*)&pGrabber);
        if (SUCCEEDED(hr))
        {
            AM_MEDIA_TYPE mt;
            hr = pGrabber->GetConnectedMediaType(&mt);
            if (SUCCEEDED(hr))
            {
                VIDEOINFOHEADER *pVih;
                if ((mt.formattype == FORMAT_VideoInfo) &&
                    (mt.cbFormat >= sizeof(VIDEOINFOHEADER)) &&
                    (mt.pbFormat != NULL) )
                {
                    pVih = (VIDEOINFOHEADER*)mt.pbFormat;
                    *width = pVih->bmiHeader.biWidth;
                    *height = pVih->bmiHeader.biHeight;
                }
                else
                {
                    hr = E_FAIL;  // Wrong format
                }

                // FreeMediaType(mt); (from MSDN)
                if (mt.cbFormat != 0)
                {
                    CoTaskMemFree((PVOID)mt.pbFormat);
                    mt.cbFormat = 0;
                    mt.pbFormat = NULL;
                }
                if (mt.pUnk != NULL)
                {
                    // Unecessary because pUnk should not be used, but safest.
                    mt.pUnk->Release();
                    mt.pUnk = NULL;
                }
            }
        }

        if (pGrabber != NULL)
        {
            pGrabber->Release();
            pGrabber = NULL;
        }
    }

    // Start the capture
    if (SUCCEEDED(hr))
        hr = g_pMediaControl->Run();

    // If init fails then ensure that you cleanup
    if (FAILED(hr))
        StopCamera();
    else
        hr = S_OK;  // Make sure we return S_OK for success

    // Cleanup
    if (pMoniker != NULL)
    {
        pMoniker->Release();
        pMoniker = NULL;
    }

    if (SUCCEEDED(hr))
        this->activeCameraIndex = camIndex;
    else
        throw gcnew COMException("Error Starting Camera", hr);
}

[更新]在下面添加了ConfigureSampleGrabber()方法

HRESULT CameraMethods::ConfigureSampleGrabber(IBaseFilter *pIBaseFilter)
{
    HRESULT hr = S_OK;
    ISampleGrabber *pGrabber = NULL;

    hr = pIBaseFilter->QueryInterface(IID_ISampleGrabber, (void**)&pGrabber);
    if (SUCCEEDED(hr))
    {
        AM_MEDIA_TYPE mt;
        ZeroMemory(&mt, sizeof(AM_MEDIA_TYPE));
        mt.majortype = MEDIATYPE_Video;
        mt.subtype = MEDIASUBTYPE_RGB24;
        mt.formattype = FORMAT_VideoInfo;
        hr = pGrabber->SetMediaType(&mt);
    }

    if (SUCCEEDED(hr))
        hr = pGrabber->SetCallback(new SampleGrabberCB(), 1);

    if (pGrabber != NULL)
    {
        pGrabber->Release();
        pGrabber = NULL;
    }

    return hr;
}

这几乎是来自CodeProject源代码的确切代码。然后，我添加了此方法来设置分辨率：

void CameraMethods::SetCaptureFormat(int camIndex, int width, int height)
{
    HRESULT hr = S_OK;
    IMoniker* pMoniker = GetMoniker(camIndex);

    IBaseFilter* pCap;
    hr=pMoniker->BindToObject(0,0,IID_IBaseFilter,(void **)&pCap);

    if(!SUCCEEDED(hr))
        return;

    IAMStreamConfig *pConfig = NULL;

    if(g_pCaptureGraphBuilder == NULL)  // no CaptureGraphBuilder initialised
        return;

    hr = g_pCaptureGraphBuilder->FindInterface(
        &PIN_CATEGORY_CAPTURE, // Preview pin.
        0,    // Any media type.
        pCap, // Pointer to the capture filter.
        IID_IAMStreamConfig, (void**)&pConfig);

    if(!SUCCEEDED(hr))
        return;

    int iCount = 0, iSize = 0;
    hr = pConfig->GetNumberOfCapabilities(&iCount, &iSize);

    // Check the size to make sure we pass in the correct structure.
    if (iSize == sizeof(VIDEO_STREAM_CONFIG_CAPS)) {

        // Use the video capabilities structure.
        for (int iFormat = 0; iFormat < iCount; iFormat++)
        {
            VIDEO_STREAM_CONFIG_CAPS scc;
            AM_MEDIA_TYPE *pmt;
            /* Note:  Use of the VIDEO_STREAM_CONFIG_CAPS structure to configure a video device is 
            deprecated. Although the caller must allocate the buffer, it should ignore the 
            contents after the method returns. The capture device will return its supported 
            formats through the pmt parameter. */
            hr = pConfig->GetStreamCaps(iFormat, &pmt, (BYTE*)&scc);
            if (SUCCEEDED(hr))
            {
                /* Examine the format, and possibly use it. */
                if (pmt->formattype == FORMAT_VideoInfo) {
                    // Check the buffer size.
                    if (pmt->cbFormat >= sizeof(VIDEOINFOHEADER))
                    {
                        VIDEOINFOHEADER *pVih =  reinterpret_cast<VIDEOINFOHEADER*>(pmt->pbFormat);
                        BITMAPINFOHEADER *bmiHeader = &pVih->bmiHeader;

                        /* Access VIDEOINFOHEADER members through pVih. */
                        if( bmiHeader->biWidth == width && bmiHeader->biHeight == height && 
                            bmiHeader->biBitCount == 24)
                        {
                            hr = pConfig->SetFormat(pmt);
                        }
                    }
                }

                // Delete the media type when you are done.
                DeleteMediaType(pmt);
            }
        }
    }
}

我已单步执行代码并验证对 SetFormat() 的调用是否已执行并返回有效的 HRESULT。但捕获的帧没有变化。

如果没有错误消息，很难知道从哪里开始。我希望这里有一些 DirectShow 专家能够看到这个问题，我什至会对一个好的老时尚居高临下感到满意“好吧，一旦缓冲区分配在过滤器堆栈和小部件被初始化为 foobar！Pft...哈哈”；）

请教我，哦 DirectShow/COM 上帝！

[更新#2]（仅供参考，奇怪的是我们不能只向该系统添加新消息，而是需要像这样编辑原始消息）

根据 Roman 的建议，我使用 GraphStudio 来查看我的图表的引擎盖。我承认我仍然不明白我到底在看什么。我发现了一个“文本报告”功能，并认为在此处发布该报告会有所帮助，以防它显示一些有价值的信息。

--------------------------------------------------
  Filters
--------------------------------------------------
  1. Smart Tee
  2. MJPEG Decompressor
  3. SampleGrabber
  4. NullRenderer
  5. WebCam

--------------------------------------------------
  Connections
--------------------------------------------------
  1. [Smart Tee]/(Capture) -> [MJPEG Decompressor]/(XForm In)
      Major:   MEDIATYPE_Video
      Subtype: MEDIASUBTYPE_MJPG
          bFixedSizeSamples:    TRUE
          bTemporalCompression: FALSE
          lSampleSize:          921600
          cbFormat:             88
      Format:  FORMAT_VideoInfo
      VIDEOINFOHEADER:
          rcSource:             (0,0,0,0)
          rcTarget:             (0,0,0,0)
          dwBitRate:            221184000
          dwBitErrorRate:       0
          AvgTimePerFrame:      333333
      BITMAPINFOHEADER:
          biSize:               40
          biWidth:              640
          biHeight:             480
          biPlanes:             1
          biBitCount:           24
          biCompression:        0x47504A4D
          biSizeImage:          921600
          biXPelsPerMeter:      0
          biYPelsPerMeter:      0
          biClrUsed:            0
          biClrImportant:       0

  2. [MJPEG Decompressor]/(XForm Out) -> [SampleGrabber]/(Input)
      Major:   MEDIATYPE_Video
      Subtype: MEDIASUBTYPE_RGB24
          bFixedSizeSamples:    TRUE
          bTemporalCompression: FALSE
          lSampleSize:          921600
          cbFormat:             88
      Format:  FORMAT_VideoInfo
      VIDEOINFOHEADER:
          rcSource:             (0,0,0,0)
          rcTarget:             (0,0,0,0)
          dwBitRate:            221184221
          dwBitErrorRate:       0
          AvgTimePerFrame:      333333
      BITMAPINFOHEADER:
          biSize:               40
          biWidth:              640
          biHeight:             480
          biPlanes:             1
          biBitCount:           24
          biCompression:        0x00000000
          biSizeImage:          921600
          biXPelsPerMeter:      0
          biYPelsPerMeter:      0
          biClrUsed:            0
          biClrImportant:       0

  3. [SampleGrabber]/(Output) -> [NullRenderer]/(In)
      Major:   MEDIATYPE_Video
      Subtype: MEDIASUBTYPE_RGB24
          bFixedSizeSamples:    TRUE
          bTemporalCompression: FALSE
          lSampleSize:          921600
          cbFormat:             88
      Format:  FORMAT_VideoInfo
      VIDEOINFOHEADER:
          rcSource:             (0,0,0,0)
          rcTarget:             (0,0,0,0)
          dwBitRate:            221184221
          dwBitErrorRate:       0
          AvgTimePerFrame:      333333
      BITMAPINFOHEADER:
          biSize:               40
          biWidth:              640
          biHeight:             480
          biPlanes:             1
          biBitCount:           24
          biCompression:        0x00000000
          biSizeImage:          921600
          biXPelsPerMeter:      0
          biYPelsPerMeter:      0
          biClrUsed:            0
          biClrImportant:       0

  4. [WebCam]/(Capture) -> [Smart Tee]/(Input)
      Major:   MEDIATYPE_Video
      Subtype: MEDIASUBTYPE_MJPG
          bFixedSizeSamples:    TRUE
          bTemporalCompression: FALSE
          lSampleSize:          921600
          cbFormat:             88
      Format:  FORMAT_VideoInfo
      VIDEOINFOHEADER:
          rcSource:             (0,0,0,0)
          rcTarget:             (0,0,0,0)
          dwBitRate:            221184000
          dwBitErrorRate:       0
          AvgTimePerFrame:      333333
      BITMAPINFOHEADER:
          biSize:               40
          biWidth:              640
          biHeight:             480
          biPlanes:             1
          biBitCount:           24
          biCompression:        0x47504A4D
          biSizeImage:          921600
          biXPelsPerMeter:      0
          biYPelsPerMeter:      0
          biClrUsed:            0
          biClrImportant:       0

[更新 #3] - 圣牛，我开始做什么了？！ 在我遇到支持的东西 Roman 的色彩空间不匹配理论。我下载了该应用，并立即修复了缓冲区太小的错误。解决该问题后，我能够生成以下报告：

Dump Version:   1.2

Using device:   Microsoft® LifeCam Studio(TM)
Interface:  USB

Pin Name:   Capture
Pin direction:  Output
Pin category:   Capture

IAMVideoCompression:    No
ISpecifyPropertyPages:  Yes
IMediaSeeking:  Yes
IPinConnection: No
IPinFlowControl:    No
IAMDroppedFrames:   No
IAMVideoProcAmp:    No
IAMVideoControlCaps:    0

Major Type  Sub Type    Format Type FixedSamples    Temporal Compression    Sample Size Max Input Size  Min Output Size Max Output Size Min-Max FPS Video Standard
Video   YUY2    VideoInfo   Fixed   NotTemporal 614400  640x480 640x480 640x480 7.50-30.00  {none}
Video   YUY2    VideoInfo2  Fixed   NotTemporal 614400  640x480 640x480 640x480 7.50-30.00  {none}
Video   YUY2    VideoInfo   Fixed   NotTemporal 1843200 1280x720    1280x720    1280x720    7.50-10.00  {none}
Video   YUY2    VideoInfo2  Fixed   NotTemporal 1843200 1280x720    1280x720    1280x720    7.50-10.00  {none}
Video   YUY2    VideoInfo   Fixed   NotTemporal 1044480 960x544 960x544 960x544 7.50-20.00  {none}
Video   YUY2    VideoInfo2  Fixed   NotTemporal 1044480 960x544 960x544 960x544 7.50-20.00  {none}
Video   YUY2    VideoInfo   Fixed   NotTemporal 716800  800x448 800x448 800x448 7.50-30.00  {none}
Video   YUY2    VideoInfo2  Fixed   NotTemporal 716800  800x448 800x448 800x448 7.50-30.00  {none}
Video   YUY2    VideoInfo   Fixed   NotTemporal 460800  640x360 640x360 640x360 7.50-30.00  {none}
Video   YUY2    VideoInfo2  Fixed   NotTemporal 460800  640x360 640x360 640x360 7.50-30.00  {none}
Video   YUY2    VideoInfo   Fixed   NotTemporal 203520  424x240 424x240 424x240 7.50-30.00  {none}
Video   YUY2    VideoInfo2  Fixed   NotTemporal 203520  424x240 424x240 424x240 7.50-30.00  {none}
Video   YUY2    VideoInfo   Fixed   NotTemporal 202752  352x288 352x288 352x288 7.50-30.00  {none}
Video   YUY2    VideoInfo2  Fixed   NotTemporal 202752  352x288 352x288 352x288 7.50-30.00  {none}
Video   YUY2    VideoInfo   Fixed   NotTemporal 153600  320x240 320x240 320x240 7.50-30.00  {none}
Video   YUY2    VideoInfo2  Fixed   NotTemporal 153600  320x240 320x240 320x240 7.50-30.00  {none}
Video   YUY2    VideoInfo   Fixed   NotTemporal 960000  800x600 800x600 800x600 7.50-20.00  {none}
Video   YUY2    VideoInfo2  Fixed   NotTemporal 960000  800x600 800x600 800x600 7.50-20.00  {none}
Video   YUY2    VideoInfo   Fixed   NotTemporal 50688   176x144 176x144 176x144 7.50-30.00  {none}
Video   YUY2    VideoInfo2  Fixed   NotTemporal 50688   176x144 176x144 176x144 7.50-30.00  {none}
Video   YUY2    VideoInfo   Fixed   NotTemporal 38400   160x120 160x120 160x120 7.50-30.00  {none}
Video   YUY2    VideoInfo2  Fixed   NotTemporal 38400   160x120 160x120 160x120 7.50-30.00  {none}
Video   YUY2    VideoInfo   Fixed   NotTemporal 4147200 1920x1080   1920x1080   1920x1080   5.00-5.00   {none}
Video   YUY2    VideoInfo2  Fixed   NotTemporal 4147200 1920x1080   1920x1080   1920x1080   5.00-5.00   {none}
Video   MJPG    VideoInfo   Fixed   NotTemporal 921600  640x480 640x480 640x480 7.50-30.00  {none}
Video   MJPG    VideoInfo2  Fixed   NotTemporal 921600  640x480 640x480 640x480 7.50-30.00  {none}
Video   MJPG    VideoInfo   Fixed   NotTemporal 6220800 1920x1080   1920x1080   1920x1080   7.50-30.00  {none}
Video   MJPG    VideoInfo2  Fixed   NotTemporal 6220800 1920x1080   1920x1080   1920x1080   7.50-30.00  {none}
Video   MJPG    VideoInfo   Fixed   NotTemporal 2764800 1280x720    1280x720    1280x720    7.50-30.00  {none}
Video   MJPG    VideoInfo2  Fixed   NotTemporal 2764800 1280x720    1280x720    1280x720    7.50-30.00  {none}
Video   MJPG    VideoInfo   Fixed   NotTemporal 1566720 960x544 960x544 960x544 7.50-30.00  {none}
Video   MJPG    VideoInfo2  Fixed   NotTemporal 1566720 960x544 960x544 960x544 7.50-30.00  {none}
Video   MJPG    VideoInfo   Fixed   NotTemporal 1075200 800x448 800x448 800x448 7.50-30.00  {none}
Video   MJPG    VideoInfo2  Fixed   NotTemporal 1075200 800x448 800x448 800x448 7.50-30.00  {none}
Video   MJPG    VideoInfo   Fixed   NotTemporal 691200  640x360 640x360 640x360 7.50-30.00  {none}
Video   MJPG    VideoInfo2  Fixed   NotTemporal 691200  640x360 640x360 640x360 7.50-30.00  {none}
Video   MJPG    VideoInfo   Fixed   NotTemporal 1440000 800x600 800x600 800x600 7.50-30.00  {none}
Video   MJPG    VideoInfo2  Fixed   NotTemporal 1440000 800x600 800x600 800x600 7.50-30.00  {none}
Video   MJPG    VideoInfo   Fixed   NotTemporal 311040  432x240 432x240 432x240 7.50-30.00  {none}
Video   MJPG    VideoInfo2  Fixed   NotTemporal 311040  432x240 432x240 432x240 7.50-30.00  {none}
Video   MJPG    VideoInfo   Fixed   NotTemporal 304128  352x288 352x288 352x288 7.50-30.00  {none}
Video   MJPG    VideoInfo2  Fixed   NotTemporal 304128  352x288 352x288 352x288 7.50-30.00  {none}
Video   MJPG    VideoInfo   Fixed   NotTemporal 76032   176x144 176x144 176x144 7.50-30.00  {none}
Video   MJPG    VideoInfo2  Fixed   NotTemporal 76032   176x144 176x144 176x144 7.50-30.00  {none}
Video   MJPG    VideoInfo   Fixed   NotTemporal 230400  320x240 320x240 320x240 7.50-30.00  {none}
Video   MJPG    VideoInfo2  Fixed   NotTemporal 230400  320x240 320x240 320x240 7.50-30.00  {none}
Video   MJPG    VideoInfo   Fixed   NotTemporal 57600   160x120 160x120 160x120 7.50-30.00  {none}
Video   MJPG    VideoInfo2  Fixed   NotTemporal 57600   160x120 160x120 160x120 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo   Fixed   NotTemporal 460800  640x480 640x480 640x480 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo2  Fixed   NotTemporal 460800  640x480 640x480 640x480 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo   Fixed   NotTemporal 1382400 1280x720    1280x720    1280x720    7.50-15.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo2  Fixed   NotTemporal 1382400 1280x720    1280x720    1280x720    7.50-15.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo   Fixed   NotTemporal 783360  960x544 960x544 960x544 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo2  Fixed   NotTemporal 783360  960x544 960x544 960x544 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo   Fixed   NotTemporal 537600  800x448 800x448 800x448 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo2  Fixed   NotTemporal 537600  800x448 800x448 800x448 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo   Fixed   NotTemporal 345600  640x360 640x360 640x360 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo2  Fixed   NotTemporal 345600  640x360 640x360 640x360 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo   Fixed   NotTemporal 152640  424x240 424x240 424x240 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo2  Fixed   NotTemporal 152640  424x240 424x240 424x240 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo   Fixed   NotTemporal 152064  352x288 352x288 352x288 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo2  Fixed   NotTemporal 152064  352x288 352x288 352x288 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo   Fixed   NotTemporal 115200  320x240 320x240 320x240 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo2  Fixed   NotTemporal 115200  320x240 320x240 320x240 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo   Fixed   NotTemporal 720000  800x600 800x600 800x600 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo2  Fixed   NotTemporal 720000  800x600 800x600 800x600 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo   Fixed   NotTemporal 38016   176x144 176x144 176x144 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo2  Fixed   NotTemporal 38016   176x144 176x144 176x144 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo   Fixed   NotTemporal 28800   160x120 160x120 160x120 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo2  Fixed   NotTemporal 28800   160x120 160x120 160x120 7.50-30.00  {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo   Fixed   NotTemporal 3110400 1920x1080   1920x1080   1920x1080   7.50-7.50   {none}
Video   {3032344D-0000-0010-8000-00AA00389B71}  VideoInfo2  Fixed   NotTemporal 3110400 1920x1080   1920x1080   1920x1080   7.50-7.50   {none}

Pin Name:   Video Camera Terminal
Pin direction:  Input
Pin category:   {3EBC7959-3310-493B-AA81-C7E132D56F71}

IAMVideoCompression:    No
ISpecifyPropertyPages:  Yes
IMediaSeeking:  No
IPinConnection: No
IPinFlowControl:    No
IAMDroppedFrames:   No
IAMVideoProcAmp:    No
IAMVideoControlCaps:    0

Major Type  Sub Type    Format Type FixedSamples    Temporal Compression    Sample Size

Answer 1

您将其放在正确的位置 - 在通过 AddFilter 将其放入图表中之后，但在连接其输出引脚之前。如果您成功获得了 HRESULT，那么您可能会期望格式发生变化，但可能会有例外，例如下游过滤器不接受此媒体类型，并且它们从一开始就开始协商。

您没有在此处显示您的ConfigureSampleGrabber，因此可能会出现这样的情况：您想要的这种媒体类型不被样本采集器接受，制作过滤器图表以尝试替代媒体类型和/或中间过滤器（例如解码器）。

您实际上可以做一些事情。

1. 为了进行故障排除，您可能需要：

   1. 将筛选器图表添加到 ROT，或者直接安装 DirectShow Spy 即可自动为您完成相同的操作
   2. 在代码中紧随 SetCaptureFormat 之后添加 MessageBox
   3. 当消息框仍在屏幕上时，使用 GraphEdit (GraphStudio) 检查您的过滤器图表并查看它在其输出引脚上枚举的媒体类型；通常，第一个媒体类型将是用于实际连接的媒体类型，因此 SetFormat 中成功的 HRESULT 基本上假设媒体类型现在位于此列表的顶部

2. 要强制使用媒体类型，您可能需要使用 IFilterGraph::ConnectDirect使用配置的引脚，它是您感兴趣的直接邻居下游引脚和媒体类型。

希望这有帮助。

Answer 2

Steve，您不应该在 SetCaptureFormat 中重建相机（从名字），而应该使用 g_pIBaseFilterCam。