我是DirectShow的新手，正在努力为我的应用添加视频流。我已经研究了很多解决方案（TouchLess，DirectShow.net等）并最终使用了这个small project on Code Project没有多少，这就是我选择它的原因;我想要一个小代码库，因为我需要快速实现这个功能。
经过一整天的阅读，实验和调试，我终于让一切都运转良好。有一个延迟，这是一个无赖，但我可以稍后担心。我此时遇到的问题是the camera is capable of 1280X720我希望使用此解决方案。然而，似乎决定以640x480捕获。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明白了。我还在我用作基础的评论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它的分辨率。我没有收到任何错误，并且从SetFormat（）返回的HRESULT为0，但相机不会改变分辨率。
要粘贴所有内容的代码太多了，但我希望包含构建图形的部分，因为我认为这就是问题所在。
以下是设置图表的代码
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);
}
[UPDATE]添加了下面的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CodeProject源代码中的确切代码。然后我添加了这个方法来设置分辨率：
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);
}
}
}
}
我已经完成了代码并验证了对SetFormat（）的调用是否已执行并返回有效的HRESULT。尽管如此，对捕获的帧没有任何更改。
没有错误消息，很难知道从哪里开始。我希望这里有一些DirectShow专家可以看到这个问题，我甚至会对一个很好的'时尚居高临下'感到高兴。嗯，是的，一旦缓冲区分配给你，你怎么期望相机改变帧大小过滤器堆栈和小部件初始化为foobar！Pft ... lol“;）
教我，哦DirectShow / COM上帝！
[更新＃2]（仅供参考，我们不能在此系统中添加新消息并需要像这样编辑原始内容，这很奇怪）
Per Roman的建议我使用GraphStudio来查看我的图表。我承认我仍然不明白我在看什么。我发现了一个“文本报告”功能，并认为如果它显示一些有价值的信息，在此发布该报告会很有帮助。
--------------------------------------------------
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] - 神圣的COW，我开始了什么？！ 为什么谷歌搜索比我之前搜索过的更深刻？came across something that supports罗马的色彩空间不匹配理论。我downloaded the app并且马上必须修复一个太小的缓冲区。解决之后，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
答案 0 :(得分：3)
你将它放在正确的位置 - 在它已经在AddFilter的图形中之后，但是在其输出引脚连接之前。如果您有成功的HRESULT，那么您可能期望更改格式，但可能有例外，例如下游过滤器不接受此媒体类型，并且他们从一开始就开始协商。
您未在此处显示您的ConfigureSampleGrabber，因此样本抓取器不会接受您想要的此媒体类型，从而尝试使用过滤器图形来尝试备用媒体类型和/或中间过滤器（例如解码器）。 / p>
您可以实际执行一些操作。
要进行疑难解答，您可能需要：
要强制使用媒体类型，您可能需要将IFilterGraph :: ConnectDirect与已配置的引脚一起使用，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。
答案 1 :(得分：0)
史蒂夫，你不应该在SetCaptureFormat重建相机（来自绰号），而是使用g_pIBaseFilterCam。