Windows Media Foundation 录制音频

问题描述

我正在使用 windows media Foundation api 来枚举我的麦克风和可用的摄像头，它们都可以工作.

I'm using the windows media foundation api to enumerate both my microphones and available cameras, which both work.

这是我的枚举代码:

class deviceInput {
public:
    deviceInput( REFGUID source );
    ~deviceInput();

    int listDevices(bool refresh = false);
    IMFActivate *getDevice(unsigned int deviceId);
    const WCHAR *getDeviceName(unsigned int deviceId);

private:
    void Clear();
    HRESULT EnumerateDevices();

    UINT32      m_count;
    IMFActivate **m_devices;
    REFGUID     m_source;
};

deviceInput::deviceInput( REFGUID source )
    : m_devices( NULL )
    , m_count( 0 )
    , m_source( source )
{   }

deviceInput::~deviceInput()
{
    Clear();
}

int deviceInput::listDevices(bool refresh)
{
    if ( refresh || !m_devices ) {
        if ( FAILED(this->EnumerateDevices()) ) return -1;
    }
    return m_count;
}

IMFActivate *deviceInput::getDevice(unsigned int deviceId)
{
    if ( deviceId >= m_count ) return NULL;

    IMFActivate *device = m_devices[deviceId];
    device->AddRef();

    return device;
}

const WCHAR *deviceInput::getDeviceName(unsigned int deviceId)
{
    if ( deviceId >= m_count ) return NULL;

    HRESULT hr = S_OK;
    WCHAR *devName = NULL;
    UINT32 length;

    hr = m_devices[deviceId]->GetAllocatedString( MF_DEVSOURCE_ATTRIBUTE_FRIENDLY_NAME, &devName, &length );
    if ( FAILED(hr) ) return NULL;

    return devName;
}

void deviceInput::Clear()
{
    if ( m_devices ) {
        for (UINT32 i = 0; i < m_count; i++) SafeRelease( &m_devices[i] );
        CoTaskMemFree( m_devices );
    }
    m_devices = NULL;
    m_count = 0;
}

HRESULT deviceInput::EnumerateDevices()
{
    HRESULT hr = S_OK;
    IMFAttributes *pAttributes = NULL;

    Clear();

    hr = MFCreateAttributes(&pAttributes, 1);
    if ( SUCCEEDED(hr) ) hr = pAttributes->SetGUID( MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE, m_source );
    if ( SUCCEEDED(hr) ) hr = MFEnumDeviceSources( pAttributes, &m_devices, &m_count );

    SafeRelease( &pAttributes );

    return hr;
}

要抓取音频或相机捕获设备，我指定 MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_AUDCAP_GUID 或 MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_VIDCAP_GUID 没有问题，我可以抓取设备的名称，以及IMF 激活.我有将网络摄像头录制到输出视频文件的代码，但是，我很难弄清楚如何将音频录制到文件中.我的印象是我需要使用 IMFSinkWriter，但我找不到任何使用音频捕获 IMFActivate 和 IMFSinkWriter 的示例.

To grab audio or camera capture devices, I specify either MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_AUDCAP_GUID or MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_VIDCAP_GUID and that works no problem, and I can grab the names of the devices, as well as the IMFActivate. I have code to record the webcam to an output video file, however, I'm having a tough time figuring out how to record the audio to a file. I'm under the impression that I need to use an IMFSinkWriter, but I can't find any examples that use an audio capture IMFActivate and IMFSinkWriter.

我不是一个 Windows api 程序员，所以我确信有一个相当直接的答案，但 COM 的东西只是有点超出我的头脑.至于音频格式，我并不在乎，只要它进入一个文件 - 可以是 wav、wma 或其他任何格式.即使我正在录制视频，我也需要将视频和音频文件分开，所以我无法弄清楚如何将音频添加到我的视频编码中.

I'm not much of a windows api programmer, so I'm sure there's a fairly straight forward answer, but COM stuff is just a bit over my head. As far as audio format, I don't really care, as long as it gets into a file - can be wav, wma, or whatever. Even though I'm recording video, I need the video and audio files separate, so I can't just figure out how to add the audio into my video encoding.

推荐答案

对于迟到的回复，我深表歉意，我希望你仍然能发现这很有价值.我最近完成了一个与您类似的项目(将网络摄像头视频与选定的麦克风一起录制到带有音频的单个视频文件中).关键是创建聚合媒体源.

I apologize for the late response, and I hope you can still find this valuable. I recently completed a project similar to yours (recording webcam video along with a selected microphone to a single video file with audio). The key is to creating an aggregate media source.

// http://msdn.microsoft.com/en-us/library/windows/desktop/dd388085(v=vs.85).aspx
HRESULT CreateAggregateMediaSource(IMFMediaSource *videoSource,
                                   IMFMediaSource *audioSource,
                                   IMFMediaSource **aggregateSource)
{
    *aggregateSource = nullptr;
    IMFCollection *pCollection = nullptr;

    HRESULT hr = ::MFCreateCollection(&pCollection);

    if (S_OK == hr)
        hr = pCollection->AddElement(videoSource);

    if (S_OK == hr)
        hr = pCollection->AddElement(audioSource);

    if (S_OK == hr)
        hr = ::MFCreateAggregateSource(pCollection, aggregateSource);

    SafeRelease(&pCollection);
    return hr;
}

在配置接收器编写器时，您将添加 2 个流(一个用于音频，一个用于视频).当然，您还将为输入流类型正确配置编写器.

When configuring the sink writer, you will add 2 streams (one for audio and one for video). Of course, you will also configure the writer correctly for the input stream types.

HRESULT        hr                  = S_OK;
IMFMediaType  *videoInputType      = nullptr;
IMFMediaType  *videoOutputType     = nullptr;
DWORD          videoOutStreamIndex = 0u;
DWORD          audioOutStreamIndex = 0u;
IMFSinkWriter *writer              = nullptr;

// [other create and configure writer]

if (S_OK == hr))
    hr = writer->AddStream(videoOutputType, &videoOutStreamIndex);    

// [more configuration code]

if (S_OK == hr)
    hr = writer->AddStream(audioOutputType, &audioOutStreamIndex);

然后在阅读样本时，您需要密切关注阅读器streamIndex，并适当地将它们发送给编写者.您还需要密切注意编解码器期望的格式.比如IEEE float vs PCM等等.祝你好运，希望现在还不算太晚.

Then when reading the samples, you will need to pay close attention to the reader streamIndex, and sending them to the writer appropriately. You will also need to pay close attention to the format that the codec expects. For instance, IEEE float vs PCM, etc. Good luck, and I hope it is not too late.

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