如何将对象连接到过滤器图？

Question

我需要做的是 - 从 DirectShow 获取解码的样本帧（如 vector<frames>）为了做到这一点我遵循这个实现 https://docs.microsoft.com/en-us/windows/win32/directshow/using-the-sample-grabber

有我的实现

bool coAudioPlayerSampleGrabber::LoadImp(SoundDataType dataType,
    unsigned char const * pData,
    int64_t dataLen)
{
    Cleanup();
    m_bReady = false;
    HRESULT hr = S_OK;

    assert(pData);
    assert(dataLen);
    m_memBuffer.resize(dataLen);
    memcpy(m_memBuffer.data(), pData, dataLen);
    m_memBufferDataType = dataType;

    m_pMediaType = new CMediaType();
    m_pMediaType->majortype = MEDIATYPE_Stream;

    switch (dataType)
    {
    case SoundDataType::WAV: m_pMediaType->subtype = MEDIASUBTYPE_WAVE; break;
    case SoundDataType::MP3: m_pMediaType->subtype = MEDIASUBTYPE_MPEG1Audio; break;
    default:            return false;
    }

    m_pMemStream = new CMemStream((BYTE*)m_memBuffer.data(), m_memBuffer.size());
    m_pMemReader = new CMemReader(m_pMemStream, m_pMediaType, &hr);
    if (FAILED(hr) || m_pMemReader == NULL)
    {
        printf("Could not create filter - HRESULT 0x%8.8X\n", hr);
        return false;
    }
    //  Make sure we don't accidentally go away!
    m_pMemReader->AddRef();

    // *** Create the Filter Graph Manager

    hr = CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&m_pGraph));

    if (FAILED(hr))
    {
        if (hr == CO_E_NOTINITIALIZED)
        {
            printf("coAudioPlayerSampleGrabberImplementation::Load: FAILED   CoCreateInstance(CLSID_FilterGraph,...) FAILED hRes: %x  (CoInitialize has not been called)\n", hr);
        }
        else
        {
            printf("coAudioPlayerSampleGrabberImplementation::Load: FAILED   CoCreateInstance(CLSID_FilterGraph FAILED hRes: %x\n", hr);
        }

        return false;
    }

    hr = m_pGraph->QueryInterface(IID_PPV_ARGS(&m_pControl));

    if (FAILED(hr))
    {
        std::cout << "coAudioPlayerSampleGrabberImplementation::Load: FAILED QueryInterface IMediaControl" << std::endl;
        return false;
    }

    hr = m_pGraph->QueryInterface(IID_PPV_ARGS(&m_pEvent));

    if (FAILED(hr))
    {
        std::cout << "coAudioPlayerSampleGrabberImplementation::Load: FAILED QueryInterface IMediaEventEx" << std::endl;
        return false;
    }   

    // *** end Create the Filter Graph Manager

    // *** Add the Sample Grabber to the Filter Graph
    // Create the Sample Grabber filter.
    hr = CoCreateInstance(CLSID_SampleGrabber, NULL, CLSCTX_INPROC_SERVER,
        IID_PPV_ARGS(&m_pGrabberF));
    if (FAILED(hr))
    {
        std::cout << "coAudioPlayerSampleGrabberImplementation::Load: FAILED CoCreateInstance CLSID_SampleGrabber" << std::endl;
        return false;
    }

    hr = m_pGraph->AddFilter(m_pGrabberF, LPCWSTR("Sample Grabber"));
    if (FAILED(hr))
    {
        std::cout << "coAudioPlayerSampleGrabberImplementation::Load: FAILED AddFilter m_pGrabberF" << std::endl;
        return false;
    }

    hr = m_pGrabberF->QueryInterface(IID_PPV_ARGS(&m_pGrabber));
    if (FAILED(hr))
    {
        std::cout << "coAudioPlayerSampleGrabberImplementation::Load: FAILED QueryInterface ISampleGrabber" << std::endl;
        return false;
    }

    // *** end Add the Sample Grabber to the Filter Graph

    // *** Set the Media Type
    hr = m_pGrabber->SetMediaType(m_pMediaType);
    if (FAILED(hr))
    {
        std::cout << "coAudioPlayerSampleGrabberImplementation::Load: FAILED SetMediaType" << std::endl;
        return false;
    }
    // *** end Set the Media Type

    IPin *ppinOut = m_pMemReader->GetPin(0);
    hr = m_pGraph->Render(ppinOut);
    if (FAILED(hr))
    {
        printf("coAudioPlayerSampleGrabberImplementation::Load: FAILED to load (Render) audio file from data (hRes: %x)\n", hr);
        return false;
    }

    m_bReady = true;

    return m_bReady;
}

我在这里遇到错误：

IPin *ppinOut = m_pMemReader->GetPin(0);
    hr = m_pGraph->Render(ppinOut);
    if (FAILED(hr))                    <------------- HERE!!
    {
        printf("TV_AudioPlayerSampleGrabberImplementation::Load: FAILED to load (Render) audio file from data (hRes: %x)\n", hr);
        return false;
    }

错误代码是 - 0x8004025F，根据这个错误 table https://docs.microsoft.com/en-us/windows/win32/directshow/error-and-success-codes 意味着

Cannot perform the requested function on an object that is not in the filter graph.

我看到文档中有一个示例 https://docs.microsoft.com/en-us/windows/win32/directshow/using-the-sample-grabber#build-the-filter-graph

但是这个示例使用文件路径作为此方法中的第一个参数 pGraph->AddSourceFilter(pszVideoFile, L"Source", &pSourceF)，我没有文件路径而是 m_pMemReader = new CMemReader(m_pMemStream, m_pMediaType, &hr).

问题是 - 如果我有 CMemReader 如何将对象连接到过滤器图？

编辑

更改了这些行

    m_pMediaType = new CMediaType();
    m_pMediaType->majortype = MEDIATYPE_Audio;            <---------- First line

    switch (dataType)
    {
        //case SoundDataType::WAV: m_pMediaType->subtype = MEDIASUBTYPE_WAVE; break;
    case SoundDataType::WAV: m_pMediaType->subtype = MEDIASUBTYPE_PCM; break;  <-------- Second line
    case SoundDataType::MP3: m_pMediaType->subtype = MEDIASUBTYPE_MPEG1Audio; break;
    default:            return false;
    }

EDIT2

为了将 m_pMemReader 添加到图表中，我添加了这一行

hr = m_pGraph->AddFilter(m_pMemReader, NULL);

然后在我将媒体类型设置为 MEDIATYPE_Audio 时出现错误 0x80040200 - The specified media type is invalid. ，如果我尝试将媒体类型设置为 MEDIATYPE_Stream 我会出现以下错误0x80040266-

Pins cannot connect because they don't support the same transport. For example, the upstream filter might require the IAsyncReader interface, while the downstream filter requires IMemInputPin.

这里有什么问题？我从这里理解的是 - 我的上游过滤器是 CMemReader * m_pMemReader; ，但是 CMemReader 在它继承自 IBaseFilter 的引擎盖下，然后我的下游是 IBaseFilter * m_pGrabberF; 也是 IBaseFilter.我在这里错过了什么？

Answer 1

DirectShow 已过时。您应该改用 MediaFoundation。我没有测试它，但我认为以下代码将解码音频并让您操作原始音频帧 (https://docs.microsoft.com/en-us/windows/win32/medfound/tutorial--decoding-audio):

IMFSourceReader *pReader = NULL;
hr = MFCreateSourceReaderFromURL(L"C:\users\video", NULL, &pReader);
if (FAILED(hr))
{
    printf("Error opening input file");
}

IMFMediaType *type = NULL;
IMFMediaType *pPartialType = NULL;
hr = MFCreateMediaType(&pPartialType);
hr = pPartialType->SetGUID(MF_MT_MAJOR_TYPE, MFMediaType_Audio);
hr = pPartialType->SetGUID(MF_MT_SUBTYPE, MFAudioFormat_PCM);
// Set this type on the source reader. The source reader will
// load the necessary decoder.
if (SUCCEEDED(hr))
{
    hr = pReader->SetCurrentMediaType((DWORD)MF_SOURCE_READER_FIRST_AUDIO_STREAM, NULL, pPartialType);
}
hr = pReader->GetCurrentMediaType((DWORD)MF_SOURCE_READER_FIRST_AUDIO_STREAM, &type);
//Do something with type which is a pointer to IMFMediaType
 
IMFSample *pSample = NULL;
IMFMediaBuffer *pBuffer = NULL;
BYTE *pAudioData = NULL;
DWORD cbBuffer = 0;
while(true){
    DWORD dwFlags = 0;
    hr = pReader->ReadSample((DWORD)MF_SOURCE_READER_FIRST_AUDIO_STREAM, 0, NULL,  &dwFlags, NULL, &pSample);
    hr = pSample->ConvertToContiguousBuffer(&pBuffer);
    hr = pBuffer->Lock(&pAudioData, NULL, &cbBuffer);
    //Do something with the pAudioData which is an array of unsigned chars of lenth cbBuffer
}

Answer 2

代码存在一些问题，整体代码片段不一致，甚至没有说无法构建它。您可能应该创建一个小项目并上传到 GitHub 作为参考。

要解决的问题是：

没有明显的理由说明为什么 m_pMemReader 会有一个属于过滤器图的合适的 pin
Sample Grabber 初始化为媒体类型 MEDIATYPE_Stream，这与您解码音频的意图相矛盾（您需要 MEDIATYPE_Audio、MEDIASUBTYPE_PCM）
使用 Render 方法通常不是一个好主意；我将离开 this reference 阅读有关使用 DirectShow Intelligent Connect 的相关问题

因为你似乎主要是试图让它工作蒙住眼睛，使用 GraphStudioNext (analog of SDK GraphEdit 工具可能是个好主意）并以交互方式构建管道以了解你需要什么样的过滤器图建造。届时您将更好地了解如何从代码构建类似的 gaph。

如何将对象连接到过滤器图？

How to connect object to the filter graph?

c++

audio

directshow