Microsoft Media Foundation官方文档翻译（20）《Stream Subtype GUIDs》《...

官方英文文档链接：https://docs.microsoft.com/en-us/windows/desktop/medfound/stream-subtype-guids

基于05/31/2018

Media Type 剩下的几篇都在此页

Stream Subtype GUIDs

Complete and Partial Media Type

Media Type Conversions

Media Type Helper Funtions

Media Type Debugging Code

Stream Subtype GUIDs

• 05/31/2018
• 2 minutes to read

下面的 subtype GUIDs 定义在 mfapi.h 头文件中。要设定这些 subtype，使用 MF_MT_SUBTYPE attribute。

当设置了这些 subtype 时，需要将 MF_MT_MAJOR_TYPE attribute 设为 MFMediaType_Stream。

GUID	Description
MFStreamFormat_MPEG2Program	MPEG-2 program stream
MFStreamFormat_MPEG2Transport	MPEG-2 transport stream.

Complete and Partial Media Types

• 05/31/2018
• 2 minutes to read

此文介绍 complete media types 与 partial media types 的区别。

Complete Media Types

complete media 是完全定义媒体流格式的类型。给定完整的媒体类型，管道组件可以分析与媒体类型关联的流数据，而不会出现歧义。

对于未压缩的格式，以下主题定义了 complete media type 所需要的 attribute：

• Audio: Uncompressed Audio Media Types
• Video: Uncompressed Video Media Types

对于压缩过的 (或编码过) 的流，complete media type 的定义由编解码器定义。

Partial Media Types

partial media 缺少完整媒体类型所需的一个或多个属性。枚举可能的媒体类型时，Microsoft Media Foundation 组件可能会保留未设置的值，以指示它可以处理任何值。例如, 视频处理器可能会保留 MF_MT_FRAME_RATE attribute，以表示它可以处理任何帧速率，并在必要时执行帧速率转换。

如果创建 partial media type，则仍应包含所知道的尽可能多的信息。但是，不要包含不确定的信息。信息缺失总比错误好。

partial media type 至少应该包含这两个信息： MF_MT_MAJOR_TYPEand MF_MT_SUBTYPE。

有时候是必须使用 complete media types：

• Media sources 必须提供 complete output types.
• 解码器在设置 input type 之后必须提供 complete output types。在设置 input type 之前，解码器也许可以提供 partial output type。
• 编码器在设置 output type 之后必须提供 complete input types，在设置 output type 之前，编码器也许可以提供 partial input type。

 

Media Type Conversions

• 05/31/2018
• 3 minutes to read

有时需要在 Media Foundation media types 和更老的 DirectShow 或 Windows Media Format SDK 里的 media type 结构之间进行转换。

From a Format Structure to a Media Foundation Type

下面的函数使用一个 format structure 来初始化 Media Foundation media type。当数据流或者文件头包含有 format structure 时也可以使用这些函数。例如 WAVE 音频文件开头就包含一个 WAVEFORMATEX 结构体。

Structure to Convert	Function
AM_MEDIA_TYPE (DirectShow) DMO_MEDIA_TYPE (DirectX Media Objects)  WM_MEDIA_TYPE (Windows Media Format SDK)  [!Note] These structures are equivalent.	MFInitMediaTypeFromAMMediaType
BITMAPINFOHEADER	MFCreateVideoMediaTypeFromBitMapInfoHeaderEx
MFVIDEOFORMAT	MFInitMediaTypeFromMFVideoFormat
MPEG1VIDEOINFO	MFInitMediaTypeFromMPEG1VideoInfo
MPEG2VIDEOINFO	MFInitMediaTypeFromMPEG2VideoInfo
VIDEOINFOHEADER2	MFInitMediaTypeFromVideoInfoHeader2
VIDEOINFOHEADER	MFInitMediaTypeFromVideoInfoHeader
WAVEFORMATEX or WAVEFORMATEXTENSIBLE	MFInitMediaTypeFromWaveFormatEx

From a Media Foundation Type to a Format Structure

下面的函数使用 Media Foundation media type 来创建或者初始化一个 format structure。

Function	Target Structure
IMFMediaType::GetRepresentation	AM_MEDIA_TYPE, MFVIDEOFORMAT, VIDEOINFOHEADER, or VIDEOINFOHEADER2
MFCreateAMMediaTypeFromMFMediaType	AM_MEDIA_TYPE
MFCreateMFVideoFormatFromMFMediaType	MFVIDEOFORMAT
MFCreateWaveFormatExFromMFMediaType	WAVEFORMATEX or WAVEFORMATEXTENSIBLE
MFInitAMMediaTypeFromMFMediaType	AM_MEDIA_TYPE

Format Mappings

下表列出了 Media Foundation attributes 与对应的 format structure 属性。并非所有的这些属性都可以直接转换。若要执行转换，参考上一节列出的函数。这个表格仅供参考。

AM_MEDIA_TYPE

Member	Attribute
bTemporalCompression	MF_MT_ALL_SAMPLES_INDEPENDENT
bFixedSizeSamples	MF_MT_FIXED_SIZE_SAMPLES
lSampleSize	MF_MT_SAMPLE_SIZE

WAVEFORMATEX, WAVEFORMATEXTENSIBLE

Member	Attribute
wFormatTag	MF_MT_SUBTYPE If wFormatTag is WAVE_FORMAT_EXTENSIBLE, the subtype is found in the SubFormat member.
nChannels	MF_MT_AUDIO_NUM_CHANNELS
nSamplesPerSec	MF_MT_AUDIO_SAMPLES_PER_SECOND
nAvgBytesPerSec	MF_MT_AUDIO_AVG_BYTES_PER_SECOND
nBlockAlign	MF_MT_AUDIO_BLOCK_ALIGNMENT
wBitsPerSample	MF_MT_AUDIO_BITS_PER_SAMPLE
wValidBitsPerSample	MF_MT_AUDIO_VALID_BITS_PER_SAMPLE
wSamplesPerBlock	MF_MT_AUDIO_SAMPLES_PER_BLOCK
dwChannelMask	MF_MT_AUDIO_CHANNEL_MASK
SubFormat	MF_MT_SUBTYPE
Extra data	MF_MT_USER_DATA

VIDEOINFOHEADER, VIDEOINFOHEADER2

Member	Attribute
dwBitRate	MF_MT_AVG_BITRATE
dwBitErrorRate	MF_MT_AVG_BIT_ERROR_RATE
AvgTimePerFrame	MF_MT_FRAME_RATE; use MFAverageTimePerFrameToFrameRateto calculate this value.
dwInterlaceFlags	MF_MT_INTERLACE_MODE
dwCopyProtectFlags	No defined equivalent
dwPictAspectRatioX, dwPictAspectRatioY	MF_MT_PIXEL_ASPECT_RATIO; must convert from picture aspect ratio to picture aspect ratio.
dwControlFlags	MF_MT_PAD_CONTROL_FLAGS. If the AMCONTROL_COLORINFO_PRESENT flag is present, set the extended color attributes described in Extended Color Information.
bmiHeader.biWidth, bmiHeader.biHeight	MF_MT_FRAME_SIZE
bmiHeader.biBitCount	Implicit in the subtype (MF_MT_SUBTYPE).
bmiHeader.biCompression	Implicit in the subtype.
bmiHeader.biSizeImage	MF_MT_SAMPLE_SIZE
Palette information	MF_MT_PALETTE

下面的属性可以从 VIDEOINFOHEADER 或 VIDEOINFOHEADER2 结构推断出来，但是这要求对格式细节有一定的了解。例如不同的 YUV 格式有不同的 stride。

• MF_MT_DEFAULT_STRIDE
• MF_MT_MINIMUM_DISPLAY_APERTURE
• MF_MT_PAN_SCAN_APERTURE

MPEG1VIDEOINFO

Member	Attribute
dwStartTimeCode	MF_MT_MPEG_START_TIME_CODE
bSequenceHeader	MF_MT_MPEG_SEQUENCE_HEADER
biXPelsPerMeter, biYPelsPerMeter	MF_MT_PIXEL_ASPECT_RATIO

MPEG2VIDEOINFO

Member	Attribute
dwStartTimeCode	MF_MT_MPEG_START_TIME_CODE
dwSequenceHeader	MF_MT_MPEG_SEQUENCE_HEADER
dwProfile	MF_MT_MPEG2_PROFILE
dwLevel	MF_MT_MPEG2_LEVEL
dwFlags	MF_MT_MPEG2_FLAGS

Examples

下面的代码使用一个 video media type，补充了一个 BITMAPINFOHEADER。注意这个转换丢掉了一些信息（隔行扫描，帧率，扩展颜色数据），然而在从视频帧保存成位图时，可能需要这些信息。

#include <dshow.h>
#include <dvdmedia.h>

// Converts a video type to a BITMAPINFO structure.
// The caller must free the structure by calling CoTaskMemFree.

// Note that this conversion loses some format information, including 
// interlacing, and frame rate.

HRESULT GetBitmapInfoHeaderFromMFMediaType(
    IMFMediaType *pType,            // Pointer to the media type.
    BITMAPINFOHEADER **ppBmih,      // Receives a pointer to the structure. 
    DWORD *pcbSize)                 // Receives the size of the structure.
{
    *ppBmih = NULL;
    *pcbSize = 0;

    GUID majorType = GUID_NULL;
    AM_MEDIA_TYPE *pmt = NULL;
    DWORD cbSize = 0;
    DWORD cbOffset = 0;
    BITMAPINFOHEADER *pBMIH = NULL;

    // Verify that this is a video type.
    HRESULT hr = pType->GetMajorType(&majorType);
    if (FAILED(hr))
    {
        goto done;
    }

    if (majorType != MFMediaType_Video)
    {
        hr = MF_E_INVALIDMEDIATYPE;
        goto done;
    }

    hr = pType->GetRepresentation(AM_MEDIA_TYPE_REPRESENTATION, (void**)&pmt);
    if (FAILED(hr))
    {
        goto done;
    }

    if (pmt->formattype == FORMAT_VideoInfo)
    {
        cbOffset = (FIELD_OFFSET(VIDEOINFOHEADER,bmiHeader));
    }
    else if (pmt->formattype == FORMAT_VideoInfo2)
    {
        cbOffset = (FIELD_OFFSET(VIDEOINFOHEADER2,bmiHeader));
    }
    else
    {
        hr = MF_E_INVALIDMEDIATYPE; // Unsupported format type.
        goto done;
    }

    if (pmt->cbFormat - cbOffset < sizeof(BITMAPINFOHEADER))
    {
        hr = E_UNEXPECTED; // Bad format size. 
        goto done;
    }

    cbSize = pmt->cbFormat - cbOffset;

    pBMIH = (BITMAPINFOHEADER*)CoTaskMemAlloc(cbSize);
    if (pBMIH == NULL)
    {
        hr = E_OUTOFMEMORY;
        goto done;
    }
    
    CopyMemory(pBMIH, pmt->pbFormat + cbOffset, cbSize);
    
    *ppBmih = pBMIH;
    *pcbSize = cbSize;

done:
    if (pmt)
    {
        pType->FreeRepresentation(AM_MEDIA_TYPE_REPRESENTATION, pmt);
    }
    return hr;
}

 

Media Type Helper Functions

• 05/31/2018
• 2 minutes to read

下面是一些与 media type 相关的函数。

Function	Description
MFAverageTimePerFrameToFrameRate	Calculates the frame rate from the average duration of a video frame.
MFCalculateImageSize	Retrieves the image size for an uncompressed video format.
MFCompareFullToPartialMediaType	Compares a full media type to a partial media type.
MFCreateMediaType	Creates an empty media type.
MFFrameRateToAverageTimePerFrame	Converts a video frame rate into a frame duration.
MFGetStrideForBitmapInfoHeader	Retrieves the minimum surface stride for a video format.
MFIsFormatYUV	Queries whether a FOURCC code or D3DFORMAT value is a YUV format.
MFValidateMediaTypeSize	Validates the size of a buffer for a video format block.
MFWrapMediaType	Creates a media type that wraps another media type.

 

Media Type Debugging Code

• 05/31/2018
• 4 minutes to read

下面的代码可以在调试时输出 media type 的内容。

// The following code enables you to view the contents of a media type while 
// debugging.

#include <strsafe.h>

LPCWSTR GetGUIDNameConst(const GUID& guid);
HRESULT GetGUIDName(const GUID& guid, WCHAR **ppwsz);

HRESULT LogAttributeValueByIndex(IMFAttributes *pAttr, DWORD index);
HRESULT SpecialCaseAttributeValue(GUID guid, const PROPVARIANT& var);

void DBGMSG(PCWSTR format, ...);

HRESULT LogMediaType(IMFMediaType *pType)
{
    UINT32 count = 0;

    HRESULT hr = pType->GetCount(&count);
    if (FAILED(hr))
    {
        return hr;
    }

    if (count == 0)
    {
        DBGMSG(L"Empty media type.\n");
    }

    for (UINT32 i = 0; i < count; i++)
    {
        hr = LogAttributeValueByIndex(pType, i);
        if (FAILED(hr))
        {
            break;
        }
    }
    return hr;
}

HRESULT LogAttributeValueByIndex(IMFAttributes *pAttr, DWORD index)
{
    WCHAR *pGuidName = NULL;
    WCHAR *pGuidValName = NULL;

    GUID guid = { 0 };

    PROPVARIANT var;
    PropVariantInit(&var);

    HRESULT hr = pAttr->GetItemByIndex(index, &guid, &var);
    if (FAILED(hr))
    {
        goto done;
    }

    hr = GetGUIDName(guid, &pGuidName);
    if (FAILED(hr))
    {
        goto done;
    }

    DBGMSG(L"\t%s\t", pGuidName);

    hr = SpecialCaseAttributeValue(guid, var);
    if (FAILED(hr))
    {
        goto done;
    }
    if (hr == S_FALSE)
    {
        switch (var.vt)
        {
        case VT_UI4:
            DBGMSG(L"%d", var.ulVal);
            break;

        case VT_UI8:
            DBGMSG(L"%I64d", var.uhVal);
            break;

        case VT_R8:
            DBGMSG(L"%f", var.dblVal);
            break;

        case VT_CLSID:
            hr = GetGUIDName(*var.puuid, &pGuidValName);
            if (SUCCEEDED(hr))
            {
                DBGMSG(pGuidValName);
            }
            break;

        case VT_LPWSTR:
            DBGMSG(var.pwszVal);
            break;

        case VT_VECTOR | VT_UI1:
            DBGMSG(L"<<byte array>>");
            break;

        case VT_UNKNOWN:
            DBGMSG(L"IUnknown");
            break;

        default:
            DBGMSG(L"Unexpected attribute type (vt = %d)", var.vt);
            break;
        }
    }

done:
    DBGMSG(L"\n");
    CoTaskMemFree(pGuidName);
    CoTaskMemFree(pGuidValName);
    PropVariantClear(&var);
    return hr;
}

HRESULT GetGUIDName(const GUID& guid, WCHAR **ppwsz)
{
    HRESULT hr = S_OK;
    WCHAR *pName = NULL;

    LPCWSTR pcwsz = GetGUIDNameConst(guid);
    if (pcwsz)
    {
        size_t cchLength = 0;
    
        hr = StringCchLength(pcwsz, STRSAFE_MAX_CCH, &cchLength);
        if (FAILED(hr))
        {
            goto done;
        }
        
        pName = (WCHAR*)CoTaskMemAlloc((cchLength + 1) * sizeof(WCHAR));

        if (pName == NULL)
        {
            hr = E_OUTOFMEMORY;
            goto done;
        }

        hr = StringCchCopy(pName, cchLength + 1, pcwsz);
        if (FAILED(hr))
        {
            goto done;
        }
    }
    else
    {
        hr = StringFromCLSID(guid, &pName);
    }

done:
    if (FAILED(hr))
    {
        *ppwsz = NULL;
        CoTaskMemFree(pName);
    }
    else
    {
        *ppwsz = pName;
    }
    return hr;
}

void LogUINT32AsUINT64(const PROPVARIANT& var)
{
    UINT32 uHigh = 0, uLow = 0;
    Unpack2UINT32AsUINT64(var.uhVal.QuadPart, &uHigh, &uLow);
    DBGMSG(L"%d x %d", uHigh, uLow);
}

float OffsetToFloat(const MFOffset& offset)
{
    return offset.value + (static_cast<float>(offset.fract) / 65536.0f);
}

HRESULT LogVideoArea(const PROPVARIANT& var)
{
    if (var.caub.cElems < sizeof(MFVideoArea))
    {
        return MF_E_BUFFERTOOSMALL;
    }

    MFVideoArea *pArea = (MFVideoArea*)var.caub.pElems;

    DBGMSG(L"(%f,%f) (%d,%d)", OffsetToFloat(pArea->OffsetX), OffsetToFloat(pArea->OffsetY), 
        pArea->Area.cx, pArea->Area.cy);
    return S_OK;
}

// Handle certain known special cases.
HRESULT SpecialCaseAttributeValue(GUID guid, const PROPVARIANT& var)
{
    if ((guid == MF_MT_FRAME_RATE) || (guid == MF_MT_FRAME_RATE_RANGE_MAX) ||
        (guid == MF_MT_FRAME_RATE_RANGE_MIN) || (guid == MF_MT_FRAME_SIZE) ||
        (guid == MF_MT_PIXEL_ASPECT_RATIO))
    {
        // Attributes that contain two packed 32-bit values.
        LogUINT32AsUINT64(var);
    }
    else if ((guid == MF_MT_GEOMETRIC_APERTURE) || 
             (guid == MF_MT_MINIMUM_DISPLAY_APERTURE) || 
             (guid == MF_MT_PAN_SCAN_APERTURE))
    {
        // Attributes that an MFVideoArea structure.
        return LogVideoArea(var);
    }
    else
    {
        return S_FALSE;
    }
    return S_OK;
}

void DBGMSG(PCWSTR format, ...)
{
    va_list args;
    va_start(args, format);

    WCHAR msg[MAX_PATH];

    if (SUCCEEDED(StringCbVPrintf(msg, sizeof(msg), format, args)))
    {
        OutputDebugString(msg);
    }
}

#ifndef IF_EQUAL_RETURN
#define IF_EQUAL_RETURN(param, val) if(val == param) return L#val
#endif

LPCWSTR GetGUIDNameConst(const GUID& guid)
{
    IF_EQUAL_RETURN(guid, MF_MT_MAJOR_TYPE);
    IF_EQUAL_RETURN(guid, MF_MT_MAJOR_TYPE);
    IF_EQUAL_RETURN(guid, MF_MT_SUBTYPE);
    IF_EQUAL_RETURN(guid, MF_MT_ALL_SAMPLES_INDEPENDENT);
    IF_EQUAL_RETURN(guid, MF_MT_FIXED_SIZE_SAMPLES);
    IF_EQUAL_RETURN(guid, MF_MT_COMPRESSED);
    IF_EQUAL_RETURN(guid, MF_MT_SAMPLE_SIZE);
    IF_EQUAL_RETURN(guid, MF_MT_WRAPPED_TYPE);
    IF_EQUAL_RETURN(guid, MF_MT_AUDIO_NUM_CHANNELS);
    IF_EQUAL_RETURN(guid, MF_MT_AUDIO_SAMPLES_PER_SECOND);
    IF_EQUAL_RETURN(guid, MF_MT_AUDIO_FLOAT_SAMPLES_PER_SECOND);
    IF_EQUAL_RETURN(guid, MF_MT_AUDIO_AVG_BYTES_PER_SECOND);
    IF_EQUAL_RETURN(guid, MF_MT_AUDIO_BLOCK_ALIGNMENT);
    IF_EQUAL_RETURN(guid, MF_MT_AUDIO_BITS_PER_SAMPLE);
    IF_EQUAL_RETURN(guid, MF_MT_AUDIO_VALID_BITS_PER_SAMPLE);
    IF_EQUAL_RETURN(guid, MF_MT_AUDIO_SAMPLES_PER_BLOCK);
    IF_EQUAL_RETURN(guid, MF_MT_AUDIO_CHANNEL_MASK);
    IF_EQUAL_RETURN(guid, MF_MT_AUDIO_FOLDDOWN_MATRIX);
    IF_EQUAL_RETURN(guid, MF_MT_AUDIO_WMADRC_PEAKREF);
    IF_EQUAL_RETURN(guid, MF_MT_AUDIO_WMADRC_PEAKTARGET);
    IF_EQUAL_RETURN(guid, MF_MT_AUDIO_WMADRC_AVGREF);
    IF_EQUAL_RETURN(guid, MF_MT_AUDIO_WMADRC_AVGTARGET);
    IF_EQUAL_RETURN(guid, MF_MT_AUDIO_PREFER_WAVEFORMATEX);
    IF_EQUAL_RETURN(guid, MF_MT_AAC_PAYLOAD_TYPE);
    IF_EQUAL_RETURN(guid, MF_MT_AAC_AUDIO_PROFILE_LEVEL_INDICATION);
    IF_EQUAL_RETURN(guid, MF_MT_FRAME_SIZE);
    IF_EQUAL_RETURN(guid, MF_MT_FRAME_RATE);
    IF_EQUAL_RETURN(guid, MF_MT_FRAME_RATE_RANGE_MAX);
    IF_EQUAL_RETURN(guid, MF_MT_FRAME_RATE_RANGE_MIN);
    IF_EQUAL_RETURN(guid, MF_MT_PIXEL_ASPECT_RATIO);
    IF_EQUAL_RETURN(guid, MF_MT_DRM_FLAGS);
    IF_EQUAL_RETURN(guid, MF_MT_PAD_CONTROL_FLAGS);
    IF_EQUAL_RETURN(guid, MF_MT_SOURCE_CONTENT_HINT);
    IF_EQUAL_RETURN(guid, MF_MT_VIDEO_CHROMA_SITING);
    IF_EQUAL_RETURN(guid, MF_MT_INTERLACE_MODE);
    IF_EQUAL_RETURN(guid, MF_MT_TRANSFER_FUNCTION);
    IF_EQUAL_RETURN(guid, MF_MT_VIDEO_PRIMARIES);
    IF_EQUAL_RETURN(guid, MF_MT_CUSTOM_VIDEO_PRIMARIES);
    IF_EQUAL_RETURN(guid, MF_MT_YUV_MATRIX);
    IF_EQUAL_RETURN(guid, MF_MT_VIDEO_LIGHTING);
    IF_EQUAL_RETURN(guid, MF_MT_VIDEO_NOMINAL_RANGE);
    IF_EQUAL_RETURN(guid, MF_MT_GEOMETRIC_APERTURE);
    IF_EQUAL_RETURN(guid, MF_MT_MINIMUM_DISPLAY_APERTURE);
    IF_EQUAL_RETURN(guid, MF_MT_PAN_SCAN_APERTURE);
    IF_EQUAL_RETURN(guid, MF_MT_PAN_SCAN_ENABLED);
    IF_EQUAL_RETURN(guid, MF_MT_AVG_BITRATE);
    IF_EQUAL_RETURN(guid, MF_MT_AVG_BIT_ERROR_RATE);
    IF_EQUAL_RETURN(guid, MF_MT_MAX_KEYFRAME_SPACING);
    IF_EQUAL_RETURN(guid, MF_MT_DEFAULT_STRIDE);
    IF_EQUAL_RETURN(guid, MF_MT_PALETTE);
    IF_EQUAL_RETURN(guid, MF_MT_USER_DATA);
    IF_EQUAL_RETURN(guid, MF_MT_AM_FORMAT_TYPE);
    IF_EQUAL_RETURN(guid, MF_MT_MPEG_START_TIME_CODE);
    IF_EQUAL_RETURN(guid, MF_MT_MPEG2_PROFILE);
    IF_EQUAL_RETURN(guid, MF_MT_MPEG2_LEVEL);
    IF_EQUAL_RETURN(guid, MF_MT_MPEG2_FLAGS);
    IF_EQUAL_RETURN(guid, MF_MT_MPEG_SEQUENCE_HEADER);
    IF_EQUAL_RETURN(guid, MF_MT_DV_AAUX_SRC_PACK_0);
    IF_EQUAL_RETURN(guid, MF_MT_DV_AAUX_CTRL_PACK_0);
    IF_EQUAL_RETURN(guid, MF_MT_DV_AAUX_SRC_PACK_1);
    IF_EQUAL_RETURN(guid, MF_MT_DV_AAUX_CTRL_PACK_1);
    IF_EQUAL_RETURN(guid, MF_MT_DV_VAUX_SRC_PACK);
    IF_EQUAL_RETURN(guid, MF_MT_DV_VAUX_CTRL_PACK);
    IF_EQUAL_RETURN(guid, MF_MT_ARBITRARY_HEADER);
    IF_EQUAL_RETURN(guid, MF_MT_ARBITRARY_FORMAT);
    IF_EQUAL_RETURN(guid, MF_MT_IMAGE_LOSS_TOLERANT); 
    IF_EQUAL_RETURN(guid, MF_MT_MPEG4_SAMPLE_DESCRIPTION);
    IF_EQUAL_RETURN(guid, MF_MT_MPEG4_CURRENT_SAMPLE_ENTRY);
    IF_EQUAL_RETURN(guid, MF_MT_ORIGINAL_4CC); 
    IF_EQUAL_RETURN(guid, MF_MT_ORIGINAL_WAVE_FORMAT_TAG);
    
    // Media types

    IF_EQUAL_RETURN(guid, MFMediaType_Audio);
    IF_EQUAL_RETURN(guid, MFMediaType_Video);
    IF_EQUAL_RETURN(guid, MFMediaType_Protected);
    IF_EQUAL_RETURN(guid, MFMediaType_SAMI);
    IF_EQUAL_RETURN(guid, MFMediaType_Script);
    IF_EQUAL_RETURN(guid, MFMediaType_Image);
    IF_EQUAL_RETURN(guid, MFMediaType_HTML);
    IF_EQUAL_RETURN(guid, MFMediaType_Binary);
    IF_EQUAL_RETURN(guid, MFMediaType_FileTransfer);

    IF_EQUAL_RETURN(guid, MFVideoFormat_AI44); //     FCC('AI44')
    IF_EQUAL_RETURN(guid, MFVideoFormat_ARGB32); //   D3DFMT_A8R8G8B8 
    IF_EQUAL_RETURN(guid, MFVideoFormat_AYUV); //     FCC('AYUV')
    IF_EQUAL_RETURN(guid, MFVideoFormat_DV25); //     FCC('dv25')
    IF_EQUAL_RETURN(guid, MFVideoFormat_DV50); //     FCC('dv50')
    IF_EQUAL_RETURN(guid, MFVideoFormat_DVH1); //     FCC('dvh1')
    IF_EQUAL_RETURN(guid, MFVideoFormat_DVSD); //     FCC('dvsd')
    IF_EQUAL_RETURN(guid, MFVideoFormat_DVSL); //     FCC('dvsl')
    IF_EQUAL_RETURN(guid, MFVideoFormat_H264); //     FCC('H264')
    IF_EQUAL_RETURN(guid, MFVideoFormat_I420); //     FCC('I420')
    IF_EQUAL_RETURN(guid, MFVideoFormat_IYUV); //     FCC('IYUV')
    IF_EQUAL_RETURN(guid, MFVideoFormat_M4S2); //     FCC('M4S2')
    IF_EQUAL_RETURN(guid, MFVideoFormat_MJPG);
    IF_EQUAL_RETURN(guid, MFVideoFormat_MP43); //     FCC('MP43')
    IF_EQUAL_RETURN(guid, MFVideoFormat_MP4S); //     FCC('MP4S')
    IF_EQUAL_RETURN(guid, MFVideoFormat_MP4V); //     FCC('MP4V')
    IF_EQUAL_RETURN(guid, MFVideoFormat_MPG1); //     FCC('MPG1')
    IF_EQUAL_RETURN(guid, MFVideoFormat_MSS1); //     FCC('MSS1')
    IF_EQUAL_RETURN(guid, MFVideoFormat_MSS2); //     FCC('MSS2')
    IF_EQUAL_RETURN(guid, MFVideoFormat_NV11); //     FCC('NV11')
    IF_EQUAL_RETURN(guid, MFVideoFormat_NV12); //     FCC('NV12')
    IF_EQUAL_RETURN(guid, MFVideoFormat_P010); //     FCC('P010')
    IF_EQUAL_RETURN(guid, MFVideoFormat_P016); //     FCC('P016')
    IF_EQUAL_RETURN(guid, MFVideoFormat_P210); //     FCC('P210')
    IF_EQUAL_RETURN(guid, MFVideoFormat_P216); //     FCC('P216')
    IF_EQUAL_RETURN(guid, MFVideoFormat_RGB24); //    D3DFMT_R8G8B8 
    IF_EQUAL_RETURN(guid, MFVideoFormat_RGB32); //    D3DFMT_X8R8G8B8 
    IF_EQUAL_RETURN(guid, MFVideoFormat_RGB555); //   D3DFMT_X1R5G5B5 
    IF_EQUAL_RETURN(guid, MFVideoFormat_RGB565); //   D3DFMT_R5G6B5 
    IF_EQUAL_RETURN(guid, MFVideoFormat_RGB8);
    IF_EQUAL_RETURN(guid, MFVideoFormat_UYVY); //     FCC('UYVY')
    IF_EQUAL_RETURN(guid, MFVideoFormat_v210); //     FCC('v210')
    IF_EQUAL_RETURN(guid, MFVideoFormat_v410); //     FCC('v410')
    IF_EQUAL_RETURN(guid, MFVideoFormat_WMV1); //     FCC('WMV1')
    IF_EQUAL_RETURN(guid, MFVideoFormat_WMV2); //     FCC('WMV2')
    IF_EQUAL_RETURN(guid, MFVideoFormat_WMV3); //     FCC('WMV3')
    IF_EQUAL_RETURN(guid, MFVideoFormat_WVC1); //     FCC('WVC1')
    IF_EQUAL_RETURN(guid, MFVideoFormat_Y210); //     FCC('Y210')
    IF_EQUAL_RETURN(guid, MFVideoFormat_Y216); //     FCC('Y216')
    IF_EQUAL_RETURN(guid, MFVideoFormat_Y410); //     FCC('Y410')
    IF_EQUAL_RETURN(guid, MFVideoFormat_Y416); //     FCC('Y416')
    IF_EQUAL_RETURN(guid, MFVideoFormat_Y41P);
    IF_EQUAL_RETURN(guid, MFVideoFormat_Y41T);
    IF_EQUAL_RETURN(guid, MFVideoFormat_YUY2); //     FCC('YUY2')
    IF_EQUAL_RETURN(guid, MFVideoFormat_YV12); //     FCC('YV12')
    IF_EQUAL_RETURN(guid, MFVideoFormat_YVYU);

    IF_EQUAL_RETURN(guid, MFAudioFormat_PCM); //              WAVE_FORMAT_PCM 
    IF_EQUAL_RETURN(guid, MFAudioFormat_Float); //            WAVE_FORMAT_IEEE_FLOAT 
    IF_EQUAL_RETURN(guid, MFAudioFormat_DTS); //              WAVE_FORMAT_DTS 
    IF_EQUAL_RETURN(guid, MFAudioFormat_Dolby_AC3_SPDIF); //  WAVE_FORMAT_DOLBY_AC3_SPDIF 
    IF_EQUAL_RETURN(guid, MFAudioFormat_DRM); //              WAVE_FORMAT_DRM 
    IF_EQUAL_RETURN(guid, MFAudioFormat_WMAudioV8); //        WAVE_FORMAT_WMAUDIO2 
    IF_EQUAL_RETURN(guid, MFAudioFormat_WMAudioV9); //        WAVE_FORMAT_WMAUDIO3 
    IF_EQUAL_RETURN(guid, MFAudioFormat_WMAudio_Lossless); // WAVE_FORMAT_WMAUDIO_LOSSLESS 
    IF_EQUAL_RETURN(guid, MFAudioFormat_WMASPDIF); //         WAVE_FORMAT_WMASPDIF 
    IF_EQUAL_RETURN(guid, MFAudioFormat_MSP1); //             WAVE_FORMAT_WMAVOICE9 
    IF_EQUAL_RETURN(guid, MFAudioFormat_MP3); //              WAVE_FORMAT_MPEGLAYER3 
    IF_EQUAL_RETURN(guid, MFAudioFormat_MPEG); //             WAVE_FORMAT_MPEG 
    IF_EQUAL_RETURN(guid, MFAudioFormat_AAC); //              WAVE_FORMAT_MPEG_HEAAC 
    IF_EQUAL_RETURN(guid, MFAudioFormat_ADTS); //             WAVE_FORMAT_MPEG_ADTS_AAC 

    return NULL;
}