Question

我正在将Windows Phone 8应用程序移植到Windows 8，而Media Engine库的工作方式似乎不同。

这是我在WP8上运行的初始化代码：

DX::ThrowIfFailed(
    MFStartup(MF_VERSION)
    );
ComPtr<IMFMediaEngineClassFactory> mediaEngineFactory;
ComPtr<IMFAttributes> mediaEngineAttributes;

// Create the class factory for the Media Engine.
DX::ThrowIfFailed(
    CoCreateInstance(CLSID_MFMediaEngineClassFactory, nullptr, CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&mediaEngineFactory))
    );

// Define configuration attributes.
DX::ThrowIfFailed(
    MFCreateAttributes(&mediaEngineAttributes, 1)
    );

ComPtr<MediaEngineNotify> notify = Make<MediaEngineNotify>();
ComPtr<IUnknown> unknownNotify;
DX::ThrowIfFailed(
    notify.As(&unknownNotify)
    );

DX::ThrowIfFailed(
    mediaEngineAttributes->SetUnknown(MF_MEDIA_ENGINE_CALLBACK, unknownNotify.Get())
    );

// Create the Media Engine.
DX::ThrowIfFailed(
    mediaEngineFactory->CreateInstance(0, mediaEngineAttributes.Get(), &m_mediaEngine)
    );

CreateInstance()抛出0xc00d36e6异常（MF_E_ATTRIBUTENOTFOUND）。

我试图搜索媒体引擎播放mp3的样本，但只能找到视频播放样本。

有什么想法吗？

Answer 1

我想出了缺失的属性。我必须添加MF_MEDIA_ENGINE_AUDIO_CATEGORY来指定媒体引擎实际上在做什么。这是一个适用于WP8和WIN8的示例：

#if PLATFORM_WINDOWS8
    DX::ThrowIfFailed(
        MFStartup(MF_VERSION)
        );
#endif
    ComPtr<IMFMediaEngineClassFactory> mediaEngineFactory;
    ComPtr<IMFAttributes> mediaEngineAttributes;

    // Create the class factory for the Media Engine.
    DX::ThrowIfFailed(
        CoCreateInstance(CLSID_MFMediaEngineClassFactory, nullptr, CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&mediaEngineFactory))
        );

    // Define configuration attributes.
    DX::ThrowIfFailed(
        MFCreateAttributes(&mediaEngineAttributes, 1)
        );

    ComPtr<MediaEngineNotify> notify = Make<MediaEngineNotify>();
    ComPtr<IUnknown> unknownNotify;
    DX::ThrowIfFailed(
        notify.As(&unknownNotify)
        );

    DX::ThrowIfFailed(
        mediaEngineAttributes->SetUnknown(MF_MEDIA_ENGINE_CALLBACK, unknownNotify.Get())
        );

    DWORD flags=0;

#if PLATFORM_WINDOWS8
    DX::ThrowIfFailed(
        mediaEngineAttributes->SetUINT32(MF_MEDIA_ENGINE_AUDIO_CATEGORY, AudioCategory_GameMedia)
        );
    flags = MF_MEDIA_ENGINE_AUDIOONLY | MF_MEDIA_ENGINE_REAL_TIME_MODE;
#endif

    // Create the Media Engine.
    DX::ThrowIfFailed(
        mediaEngineFactory->CreateInstance(flags, mediaEngineAttributes.Get(), &m_mediaEngine)
        );

在Windows 8上使用Media Engine播放音乐

1 个答案: