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The Windows Media MPEG4 V1/V2 decoder decodes MPEG4 V1/V2 video streams.
Class Identifier
The class identifier (CLSID) for the Windows Media MPEG4 V1/V2 decoder is represented by the constant CLSID_CMpeg4DecMediaObject. You can create an instance of the MPEG4 V1/V2 decoder by calling CoCreateInstance.
Formats
The Windows Media MPEG4 V1/V2 decoder supports the following input media types.
- MEDIASUBTYPE_MPG4
- MEDIASUBTYPE_mpg4
- MEDIASUBTYPE_MP42
- MEDIASUBTYPE_mp42
The Windows Media MPEG4 V1/V2 decoder supports the following output media subtypes when it is acting as a DirectX Media Object (DMO).
- MEDIASUBTYPE_YUY2
- MEDIASUBTYPE_UYVY
- MEDIASUBTYPE_RGB32
- MEDIASUBTYPE_RGB24
- MEDIASUBTYPE_RGB565
- MEDIASUBTYPE_RGB8
- MEDIASUBTYPE_RGB555
The Windows Media MPEG4 V1/V2 decoder supports the following output media subtypes when it is acting as a Media Foundation Transform (MFT).
- MFVideoFormat_YUY2
- MFVideoFormat_UYVY
- MFVideoFormat_RGB32
- MFVideoFormat_RGB24
- MFVideoFormat_RGB565
- MFVideoFormat_RGB8
- MFVideoFormat_RGB555
Remarks
The Windows Media MPEG4 V1/V2 decoder object exposes the IMediaObject interface so that the object can be used as a DirectX Media Object (DMO), and it exposes the IMFTransform interface so that the object can be used as a Media Foundation Transform (MFT). The object has the same class identifier (CLSID) regardless of whether it acts as a DMO or an MFT.
An MPEG4 V1/V2 decoder behaves as a DMO or an MFT depending on which interfaces you obtain and which version of Windows is running. The following table shows the conditions under which an MPEG4 V1/V2 decoder behaves as a DMO or an MFT.
| Operating system | Decoder behavior |
|---|---|
| Windows XP | An MPEG4 V1/V2 decoder always behaves as a DMO. |
| Windows Vista and Windows 7 | By default, an MPEG4 V1/V2 decoder behaves as a DMO. If you obtain an Video Subtype GUIDs interface on an MPEG4 V1/V2 decoder, it behaves as an MFT. |
The globally unique identifiers (GUIDs) for RGB media subtypes differ depending on whether a decoder is acting as a DMO or an MFT. The GUIDs for non-RGB media subtypes are the same, regardless of whether a decoder is acting as a DMO or an MFT. For information about the GUIDs that represent video subtypes, see Video Subtype GUIDs.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client |
Windows XP [desktop apps only] |
| Minimum supported server |
Windows Server 2003 [desktop apps only] |
| Header |
|
| DLL |
|
See also