通过将字节样本直接写入Enhanced Video Renderer（EVR）接收器，我可以显示mp4视频的视频流（感谢在Media Foundation EVR no video displaying上回答）。
我想做同样的事情，但要使用网络摄像头。我目前遇到的问题是，我的网络摄像头仅支持RGB24和I420格式，据我所知，EVR仅支持RGB32。我相信在某些Media Foundation方案中，只要在该过程中注册了CColorConvertDMO类，转换就会自动发生。我已经做到了，但是我怀疑由于我将样本写入EVR的方式，因此没有调用颜色转换。
我的问题是我应该采取哪种方法来允许从网络摄像头IMFSourceReader中读取RGB24样本以允许写入EVR IMFStreamSink？
我的完整示例程序为here，但由于需要Media Foundation管道而非常长。下面是我尝试将EVR接收器媒体类型与网络摄像头源媒体类型匹配的块。
问题是MF_MT_SUBTYPE属性的设置。据我所知，对于EVR，tt必须为MFVideoFormat_RGB32，但我的网络摄像头仅接受MFVideoFormat_RGB24。
IMFMediaSource* pVideoSource = NULL;
IMFSourceReader* pVideoReader = NULL;
IMFMediaType* videoSourceOutputType = NULL, * pvideoSourceModType = NULL;
IMFMediaType* pVideoOutType = NULL;
IMFMediaType* pHintMediaType = NULL;
IMFMediaSink* pVideoSink = NULL;
IMFStreamSink* pStreamSink = NULL;
IMFSinkWriter* pSinkWriter = NULL;
IMFMediaTypeHandler* pSinkMediaTypeHandler = NULL, * pSourceMediaTypeHandler = NULL;
IMFPresentationDescriptor* pSourcePresentationDescriptor = NULL;
IMFStreamDescriptor* pSourceStreamDescriptor = NULL;
IMFVideoRenderer* pVideoRenderer = NULL;
IMFVideoDisplayControl* pVideoDisplayControl = NULL;
IMFGetService* pService = NULL;
IMFActivate* pActive = NULL;
IMFPresentationClock* pClock = NULL;
IMFPresentationTimeSource* pTimeSource = NULL;
IDirect3DDeviceManager9* pD3DManager = NULL;
IMFVideoSampleAllocator* pVideoSampleAllocator = NULL;
IMFSample* pD3DVideoSample = NULL;
RECT rc = { 0, 0, VIDEO_WIDTH, VIDEO_HEIGHT };
BOOL fSelected = false;
CHECK_HR(CoInitializeEx(NULL, COINIT_APARTMENTTHREADED | COINIT_DISABLE_OLE1DDE),
"COM initialisation failed.");
CHECK_HR(MFStartup(MF_VERSION),
"Media Foundation initialisation failed.");
//CHECK_HR(ListCaptureDevices(DeviceType::Video),
// "Error listing video capture devices.");
// Need the color converter DSP for conversions between YUV, RGB etc.
CHECK_HR(MFTRegisterLocalByCLSID(
__uuidof(CColorConvertDMO),
MFT_CATEGORY_VIDEO_PROCESSOR,
L"",
MFT_ENUM_FLAG_SYNCMFT,
0,
NULL,
0,
NULL),
"Error registering colour converter DSP.");
// Create a separate Window and thread to host the Video player.
CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)InitializeWindow, NULL, 0, NULL);
Sleep(1000);
if (_hwnd == nullptr)
{
printf("Failed to initialise video window.\n");
goto done;
}
if (_hwnd == nullptr)
{
printf("Failed to initialise video window.\n");
goto done;
}
// ----- Set up Video sink (Enhanced Video Renderer). -----
CHECK_HR(MFCreateVideoRendererActivate(_hwnd, &pActive),
"Failed to created video rendered activation context.");
CHECK_HR(pActive->ActivateObject(IID_IMFMediaSink, (void**)&pVideoSink),
"Failed to activate IMFMediaSink interface on video sink.");
// Initialize the renderer before doing anything else including querying for other interfaces,
// see https://msdn.microsoft.com/en-us/library/windows/desktop/ms704667(v=vs.85).aspx.
CHECK_HR(pVideoSink->QueryInterface(__uuidof(IMFVideoRenderer), (void**)&pVideoRenderer),
"Failed to get video Renderer interface from EVR media sink.");
CHECK_HR(pVideoRenderer->InitializeRenderer(NULL, NULL),
"Failed to initialise the video renderer.");
CHECK_HR(pVideoSink->QueryInterface(__uuidof(IMFGetService), (void**)&pService),
"Failed to get service interface from EVR media sink.");
CHECK_HR(pService->GetService(MR_VIDEO_RENDER_SERVICE, __uuidof(IMFVideoDisplayControl), (void**)&pVideoDisplayControl),
"Failed to get video display control interface from service interface.");
CHECK_HR(pVideoDisplayControl->SetVideoWindow(_hwnd),
"Failed to SetVideoWindow.");
CHECK_HR(pVideoDisplayControl->SetVideoPosition(NULL, &rc),
"Failed to SetVideoPosition.");
CHECK_HR(pVideoSink->GetStreamSinkByIndex(0, &pStreamSink),
"Failed to get video renderer stream by index.");
CHECK_HR(pStreamSink->GetMediaTypeHandler(&pSinkMediaTypeHandler),
"Failed to get media type handler for stream sink.");
DWORD sinkMediaTypeCount = 0;
CHECK_HR(pSinkMediaTypeHandler->GetMediaTypeCount(&sinkMediaTypeCount),
"Failed to get sink media type count.");
std::cout << "Sink media type count: " << sinkMediaTypeCount << "." << std::endl;
// ----- Set up Video source (is either a file or webcam capture device). -----
#if USE_WEBCAM_SOURCE
CHECK_HR(GetVideoSourceFromDevice(WEBCAM_DEVICE_INDEX, &pVideoSource, &pVideoReader),
"Failed to get webcam video source.");
#else
CHECK_HR(GetVideoSourceFromFile(MEDIA_FILE_PATH, &pVideoSource, &pVideoReader),
"Failed to get file video source.");
#endif
CHECK_HR(pVideoReader->GetCurrentMediaType((DWORD)MF_SOURCE_READER_FIRST_VIDEO_STREAM, &videoSourceOutputType),
"Error retrieving current media type from first video stream.");
CHECK_HR(pVideoReader->SetStreamSelection((DWORD)MF_SOURCE_READER_FIRST_VIDEO_STREAM, TRUE),
"Failed to set the first video stream on the source reader.");
CHECK_HR(pVideoSource->CreatePresentationDescriptor(&pSourcePresentationDescriptor),
"Failed to create the presentation descriptor from the media source.");
CHECK_HR(pSourcePresentationDescriptor->GetStreamDescriptorByIndex(0, &fSelected, &pSourceStreamDescriptor),
"Failed to get source stream descriptor from presentation descriptor.");
CHECK_HR(pSourceStreamDescriptor->GetMediaTypeHandler(&pSourceMediaTypeHandler),
"Failed to get source media type handler.");
DWORD srcMediaTypeCount = 0;
CHECK_HR(pSourceMediaTypeHandler->GetMediaTypeCount(&srcMediaTypeCount),
"Failed to get source media type count.");
std::cout << "Source media type count: " << srcMediaTypeCount << ", is first stream selected " << fSelected << "." << std::endl;
std::cout << "Default output media type for source reader:" << std::endl;
std::cout << GetMediaTypeDescription(videoSourceOutputType) << std::endl << std::endl;
// ----- Create a compatible media type and set on the source and sink. -----
// Set the video input type on the EVR sink.
CHECK_HR(MFCreateMediaType(&pVideoOutType), "Failed to create video output media type.");
CHECK_HR(pVideoOutType->SetGUID(MF_MT_MAJOR_TYPE, MFMediaType_Video), "Failed to set video output media major type.");
CHECK_HR(pVideoOutType->SetGUID(MF_MT_SUBTYPE, MFVideoFormat_RGB32), "Failed to set video sub-type attribute on media type.");
CHECK_HR(pVideoOutType->SetUINT32(MF_MT_INTERLACE_MODE, MFVideoInterlace_Progressive), "Failed to set interlace mode attribute on media type.");
CHECK_HR(pVideoOutType->SetUINT32(MF_MT_ALL_SAMPLES_INDEPENDENT, TRUE), "Failed to set independent samples attribute on media type.");
CHECK_HR(MFSetAttributeRatio(pVideoOutType, MF_MT_PIXEL_ASPECT_RATIO, 1, 1), "Failed to set pixel aspect ratio attribute on media type.");
CHECK_HR(CopyAttribute(videoSourceOutputType, pVideoOutType, MF_MT_FRAME_SIZE), "Failed to copy video frame size attribute to media type.");
CHECK_HR(CopyAttribute(videoSourceOutputType, pVideoOutType, MF_MT_FRAME_RATE), "Failed to copy video frame rate attribute to media type.");
//CHECK_HR(GetSupportedMediaType(pMediaTypeHandler, &pVideoOutType),
// "Failed to get supported media type.");
std::cout << "Custom media type defined as:" << std::endl;
std::cout << GetMediaTypeDescription(pVideoOutType) << std::endl << std::endl;
auto doesSinkSupport = pSinkMediaTypeHandler->IsMediaTypeSupported(pVideoOutType, &pHintMediaType);
if (doesSinkSupport != S_OK) {
std::cout << "Sink does not support desired media type." << std::endl;
goto done;
}
else {
CHECK_HR(pSinkMediaTypeHandler->SetCurrentMediaType(pVideoOutType),
"Failed to set input media type on EVR sink.");
}
// The block below returnedalways failed furing testing. My guess is the source media type handler
// is not aligned with the video reader somehow.
/*auto doesSrcSupport = pSourceMediaTypeHandler->IsMediaTypeSupported(pVideoOutType, &pHintMediaType);
if (doesSrcSupport != S_OK) {
std::cout << "Source does not support desired media type." << std::endl;
goto done;
}
else {
CHECK_HR(pSourceMediaTypeHandler->SetCurrentMediaType(pVideoOutType),
"Failed to set output media type on source reader.");
}*/
CHECK_HR(pVideoReader->SetCurrentMediaType((DWORD)MF_SOURCE_READER_FIRST_VIDEO_STREAM, NULL, pVideoOutType),
"Failed to set output media type on source reader.");
// ----- Source and sink now configured. Set up remaining infrastructure and then start sampling. -----
我需要手动连接颜色转换MFT（我很确定某些Media Foundation方案会自动将其连接，但可能仅在使用拓扑时才连接），并调整提供给EVR的Direct3D IMFSample上的时钟设置。
正在工作example。
源阅读器通常能够执行此转换：RGB24-> RGB32。
据我所知，EVR仅支持RGB32
不是，这仅取决于您的视频处理器：mofo7777 / Stackoverflow
在MFVideoEVR项目下，将所有MFVideoFormat_RGB32替换为MFVideoFormat_NV12，它应与NVidia GPU卡一起使用。改变睡眠（20）;带睡眠（40）;在Main.cpp（HRESULT DisplayVideo（...））中，因为使用NV12格式进行了更优化（25 fps视频帧速率的值）。
关于您的问题：
您可以在不进行颜色转换MFT的情况下进行操作。从MFVideoEVR，有两件事需要更新：
这里的源代码：mofo7777 / Stackoverflow
在MFVideoCaptureEVR项目下。