C++ ComPtr::SetGUID方法代码示例

void MediaStreamer::Initialize(__in const WCHAR* url)
{
    Microsoft::WRL::ComPtr<IMFMediaType> outputMediaType;
    Microsoft::WRL::ComPtr<IMFMediaType> mediaType;
  
    ThrowIfFailed(
        MFStartup(MF_VERSION)
        );

	WCHAR filePath[MAX_PATH] = {0};
	if ((wcslen(url) > 1 && url[1] == ':'))
	{
		// path start with "x:", is absolute path
		wcscat_s(filePath, url);
	}
	else if (wcslen(url) > 0 
		&& (L'/' == url[0] || L'\\' == url[0]))
	{
		// path start with '/' or '\', is absolute path without driver name
		wcscat_s(filePath, m_installedLocationPath->Data());
		// remove '/' or '\\'
		wcscat_s(filePath, (const WCHAR*)url[1]);
	}else
	{
		wcscat_s(filePath, m_installedLocationPath->Data());
		wcscat_s(filePath, url);
	}

    ThrowIfFailed(
        MFCreateSourceReaderFromURL(filePath, nullptr, &m_reader)
        );

    // Set the decoded output format as PCM
    // XAudio2 on Windows can process PCM and ADPCM-encoded buffers.
    // When using MF, this sample always decodes into PCM.

    ThrowIfFailed(
        MFCreateMediaType(&mediaType)
        );

    ThrowIfFailed(
        mediaType->SetGUID(MF_MT_MAJOR_TYPE, MFMediaType_Audio)
        );

    ThrowIfFailed(
        mediaType->SetGUID(MF_MT_SUBTYPE, MFAudioFormat_PCM)
        );

    ThrowIfFailed(
        m_reader->SetCurrentMediaType(MF_SOURCE_READER_FIRST_AUDIO_STREAM, 0, mediaType.Get())
        );

    // Get the complete WAVEFORMAT from the Media Type
    ThrowIfFailed(
        m_reader->GetCurrentMediaType(MF_SOURCE_READER_FIRST_AUDIO_STREAM, &outputMediaType)
        );

    uint32 formatSize = 0;
    WAVEFORMATEX* waveFormat;
    ThrowIfFailed(
        MFCreateWaveFormatExFromMFMediaType(outputMediaType.Get(), &waveFormat, &formatSize)
        );
    CopyMemory(&m_waveFormat, waveFormat, sizeof(m_waveFormat));
    CoTaskMemFree(waveFormat);

    // Get the total length of the stream in bytes
    PROPVARIANT var;
    ThrowIfFailed(
        m_reader->GetPresentationAttribute(MF_SOURCE_READER_MEDIASOURCE, MF_PD_DURATION, &var)
        );
    LONGLONG duration = var.uhVal.QuadPart;
    double durationInSeconds = (duration / static_cast<double>(10000000)); // duration is in 100ns units, convert to seconds
    m_maxStreamLengthInBytes = static_cast<unsigned int>(durationInSeconds * m_waveFormat.nAvgBytesPerSec);

    // Round up the buffer size to the nearest four bytes
    m_maxStreamLengthInBytes = (m_maxStreamLengthInBytes + 3) / 4 * 4;
}

    // Create the source reader on the url (file) with the low latency attributes
    //
    DX::ThrowIfFailed(
        MFCreateSourceReaderFromURL(url->Data(), lowLatencyAttribute.Get(), &m_reader)
        );

    // Set the decoded output format as PCM
    // XAudio2 on Windows can process PCM and ADPCM-encoded buffers.
    // When using MF, this sample always decodes into PCM.

    DX::ThrowIfFailed(
        MFCreateMediaType(&mediaType)
        );

    DX::ThrowIfFailed(
        mediaType->SetGUID(MF_MT_MAJOR_TYPE, MFMediaType_Audio)
        );

    DX::ThrowIfFailed(
        mediaType->SetGUID(MF_MT_SUBTYPE, MFAudioFormat_PCM)
        );

    DX::ThrowIfFailed(
        m_reader->SetCurrentMediaType(MF_SOURCE_READER_FIRST_AUDIO_STREAM, 0, mediaType.Get())
        );

    // Get the complete WAVEFORMAT from the Media Type
    DX::ThrowIfFailed(
        m_reader->GetCurrentMediaType(MF_SOURCE_READER_FIRST_AUDIO_STREAM, &outputMediaType)
        );

void MediaStreamer::Initialize(_In_ const WCHAR* url)
{
    Microsoft::WRL::ComPtr<IMFMediaType> outputMediaType;
    Microsoft::WRL::ComPtr<IMFMediaType> mediaType;

    DX::ThrowIfFailed(
        MFStartup(MF_VERSION)
        );

    DX::ThrowIfFailed(
        MFCreateSourceReaderFromURL(url, nullptr, &m_reader)
        );

    // Set the decoded output format as PCM.
    // XAudio2 on Windows can process PCM and ADPCM-encoded buffers.
    // When this sample uses Media Foundation, it always decodes into PCM.

    DX::ThrowIfFailed(
        MFCreateMediaType(&mediaType)
        );

    DX::ThrowIfFailed(
        mediaType->SetGUID(MF_MT_MAJOR_TYPE, MFMediaType_Audio)
        );

    DX::ThrowIfFailed(
        mediaType->SetGUID(MF_MT_SUBTYPE, MFAudioFormat_PCM)
        );

    DX::ThrowIfFailed(
        m_reader->SetCurrentMediaType(MF_SOURCE_READER_FIRST_AUDIO_STREAM, 0, mediaType.Get())
        );

    // Get the complete WAVEFORMAT from the Media Type.
    DX::ThrowIfFailed(
        m_reader->GetCurrentMediaType(MF_SOURCE_READER_FIRST_AUDIO_STREAM, &outputMediaType)
        );

    uint32 formatSize = 0;
    WAVEFORMATEX* waveFormat;
    DX::ThrowIfFailed(
        MFCreateWaveFormatExFromMFMediaType(outputMediaType.Get(), &waveFormat, &formatSize)
        );
    CopyMemory(&m_waveFormat, waveFormat, sizeof(m_waveFormat));
    CoTaskMemFree(waveFormat);

    // Get the total length of the stream, in bytes.
    PROPVARIANT var;
    DX::ThrowIfFailed(
        m_reader->GetPresentationAttribute(MF_SOURCE_READER_MEDIASOURCE, MF_PD_DURATION, &var)
        );

    // duration is in 100ns units; convert to seconds, and round up
    // to the nearest whole byte.
    ULONGLONG duration = var.uhVal.QuadPart;
    m_maxStreamLengthInBytes =
        static_cast<unsigned int>(
            ((duration * static_cast<ULONGLONG>(m_waveFormat.nAvgBytesPerSec)) + 10000000) /
            10000000
            );
}