如何在DirectShow中将捕获的视频/音频渲染并保存为自定义文件/过滤器格式？

Question

Basiclly, I want to capture audio/video. Run it through a mp4 muxer and save it to a file on disk. Before I used ICaptureGraphBuilder2, but it seems unusuable when saving to custom formats.

My code so far,

I enumerate video/audio devices. In this sample I only try to capture audio. I get the correct device and use GetPin to enumerate the filters pins to get its output pin.

hr = pMoniker2->BindToObject(0, 0, IID_IBaseFilter, (void**)&pSrc2);
hr = pGraph->AddFilter(pSrc2, L"AudioCap");

hr = GetPin(pSrc2, PINDIR_OUTPUT, &outPin);

This is the custom filter, a MP4 muxer. It properly loads and I can get the input pin and connect it with my output pin. So far so good.

HRESULT hr = CreateObjectFromPath(TEXT("c:\\filters\\mp4mux.dll"), clsid, &pUnk);
if (SUCCEEDED(hr))
{
    IBaseFilterPtr pFilter = pUnk;
    HRESULT hr = pGraph->AddFilter(pFilter, L"Private Filter");
    hr = GetPin(pFilter, PINDIR_INPUT, &inPin);
}

hr = pGraph->Connect(outPin, inPin);

This is where I get lost, I can't find out how to take the next steps to Render and save the output to a file on disk. So any help with the next steps would be greatfully appreciated, thanks in advance!

EDIT: Filesink code

AM_MEDIA_TYPE mType;

mType.majortype = MEDIATYPE_Video;
mType.subtype = MEDIASUBTYPE_H264;
mType.bFixedSizeSamples = FALSE;
mType.bTemporalCompression = TRUE;
mType.lSampleSize = 0;
mType.formattype = FORMAT_None;
mType.pUnk = NULL;
mType.cbFormat = 0;
mType.pbFormat = NULL;
//Not 100% sure about the setup of the media format.

IBaseFilter * iFiltera = NULL; 
IFileSinkFilter* iFilter = NULL; 
IGraphBuilder *pGraph;

hr = pMoniker2->BindToObject(0, 0, IID_IBaseFilter, (void**)&pSrc2); //audio capture
hr = CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER,  IID_IGraphBuilder, (void**)&pGraph);
hr = CoCreateInstance(CLSID_FileWriter, NULL, CLSCTX_INPROC_SERVER, IID_IBaseFilter, (void**)&iFiltera);

hr = pBuild->SetFiltergraph(pGraph);

hr = pGraph->AddFilter(pSrc2, L"AudioCap");
hr = GetPin(pSrc2, PINDIR_OUTPUT, &outPin); //ADDED

hr = pGraph->AddFilter(iFiltera, L"FileWriter");
hr = iFiltera->QueryInterface(IID_IFileSinkFilter, (void**)&iFilter);

iFilter->SetFileName((LPCOLESTR)"c:\\wav\\tester.mp4", NULL); //UPDATED mType set to NULL

HRESULT hr = CreateObjectFromPath(TEXT("c:\\filters\\mp4mux.dll"), clsid, &pUnk);

IBaseFilterPtr pFilter = pUnk;
if (SUCCEEDED(hr))
{

    HRESULT hr = pGraph->AddFilter(pFilter, L"Private Filter");
    hr = GetPin(pFilter, PINDIR_INPUT, &inPin); //mux in

    hr = GetPin(pFilter, PINDIR_OUTPUT, &mOutPin); //mux out
    hr = GetPin(iFiltera, PINDIR_INPUT, &filePin); // filewriter in
}

hr = pGraph->Connect(outPin, inPin); //connect audio out and mux in
hr = pGraph->Connect(mOutPin, filePin); //connect mux out and file in; Error 0x80040217(VFW_E_CANNOT_CONNECT?) //works now

//ADDED code
IMediaControl *pMC = NULL;
hr = pGraph->QueryInterface(IID_IMediaControl, (void **)&pMC);

hr = pMC->Run();
Sleep(4000);
hr = pMC->Stop();  

Answer 1

You need to have an idea what filter graph topology you need for specific task. You are doing capture, here - fine. So you have audio capture filter you provided code snippet for. Then you either compress audio (where your preferred choice should be AAC AKA MPEG-4 Part 3, provided that you are to produce MP4 file), or keep audio uncompressed PCM. Then you connect MPEG-4 multiplexer as you do. The multiplexer produces output stream and you are expected to complete the pipeline with File Writer Filter .

You can manually build the chain in GraphEdit SDK application (or there are alternate richer tools). Your filter graph looks like this:

Note that you can expose filter graph in your application, and connect to it remotely and inspect the topology. This makes debugging much easier. Starting/stopping the filter graph ( IMediaControl::Run , ::Stop from code) creates you the file.

My understanding is that you get lost immediately after adding multiplexer. Now you need to find its output pin, add File Writer , query its IFileSinkFilter , set the destination file name using it, find its input pin, connect the two unconnected pins (mux output, writer input). Your pipeline is ready to run.