枚举所有已安装的 Windows 媒体编解码器

[与此页面关联的功能 Windows Media Format 11 SDK 是旧版功能。 它已被源读取器和接收器编写器取代。 源读取器和接收器编写器已针对Windows 10和Windows 11进行了优化。 Microsoft 强烈建议新代码尽可能使用源读取器和接收器编写器，而不是 Windows Media Format 11 SDK。 如果可能，Microsoft 建议重写使用旧 API 的现有代码以使用新 API。]

编解码器信息接口都使用编解码器索引来标识单个编解码器。 编解码器单独为音频和视频编制索引。 在一种类型的编解码器中，索引范围从 0 到比该类型的编解码器数少一个。

以下示例代码演示如何获取与每个编解码器关联的索引。 若要在应用程序中编译此代码，请包含 stdio.h。

HRESULT GetCodecNames(IWMCodecInfo3* pCodecInfo)
{
    HRESULT hr = S_OK;
    DWORD   cCodecs  = 0;
    WCHAR*  pwszCodecName  = NULL;
    DWORD   cchCodecName     = 0;
    
    // Retrieve the number of supported audio codecs on the system.
    hr = pCodecInfo->GetCodecInfoCount(WMMEDIATYPE_Audio, &cCodecs);

    if(SUCCEEDED(hr))
        printf("Number of audio codecs: %d\n\n", cCodecs);
    else
    {
        printf("Could not get the count of audio codecs.\n");
        return hr;
    }

    // Loop through all the audio codecs.
    for(DWORD dwCodecIndex = 0; dwCodecIndex < cCodecs; dwCodecIndex++)
    {
        // Get the codec name:
        // First, get the size of the name.
        hr = pCodecInfo->GetCodecName(WMMEDIATYPE_Audio, 
                                      dwCodecIndex, 
                                      NULL, 
                                      &cchCodecName);
        if(FAILED(hr))
        {
            printf("Could not get the size of the codec name.\n");
            return hr;
        }

        // Allocate a string of the appropriate size.
        pwszCodecName = new WCHAR[cchCodecName];
        if(pwszCodecName == NULL)
        {
            printf("Could not allocate memory.\n");
            return E_OUTOFMEMORY;
        }

        // Retrieve the codec name.
        hr = pCodecInfo->GetCodecName(WMMEDIATYPE_Audio, 
                                      dwCodecIndex, 
                                      pwszCodecName, 
                                      &cchCodecName);
        if(FAILED(hr))
        {
            delete[] pwszCodecName;
            printf("Could not get the codec name.\n");
            return hr;
        }

        // Print the codec name.
        printf("%d %S\n", dwCodecIndex, pwszCodecName);

        // Clean up for the next iteration.
        delete[] pwszCodecName;
        pwszCodecName = NULL;
        cchCodecName  = 0;
    }

    // Retrieve the number of supported video codecs on the system.
    hr = pCodecInfo->GetCodecInfoCount(WMMEDIATYPE_Video, &cCodecs);

    if(SUCCEEDED(hr))
        printf("\n\nNumber of video codecs: %d.\n\n", cCodecs);
    else
    {
        printf("Could not get the count of video codecs.\n");
        return hr;
    }

    // Loop through all the video codecs.
    for(dwCodecIndex = 0; dwCodecIndex < cCodecs; dwCodecIndex++)
    {
        // Get the codec name:
        // First, get the size of the name.
        hr = pCodecInfo->GetCodecName(WMMEDIATYPE_Video, 
                                      dwCodecIndex, 
                                      NULL, 
                                      &cchCodecName);
        if(FAILED(hr))
        {
            printf("Could not get the size of the codec name.\n");
            return hr;
        }

        // Allocate a string of the appropriate size.
        pwszCodecName = new WCHAR[cchCodecName];
        if(pwszCodecName == NULL)
        {
            printf("Could not allocate memory.\n");
            return E_OUTOFMEMORY;
        }

        // Retrieve the codec name.
        hr = pCodecInfo->GetCodecName(WMMEDIATYPE_Video, 
                                      dwCodecIndex, 
                                      pwszCodecName, 
                                      &cchCodecName);
        if(FAILED(hr))
        {
            printf("Could not get the codec name.\n");
            return hr;
        }

        // Print the codec name.
        printf("%d %S\n", dwCodecIndex, pwszCodecName);

        delete[] pwszCodecName;
        pwszCodecName = NULL;
        cchCodecName  = 0;
    }
    return S_OK;
}

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