Windows Media Video 9 Decoder
The Windows Media Video 9 decoder decodes video streams that were encoded by the Windows Media Video Encoder. The encoder and decoder support the following four categories of encoded video.
- Windows Media Video 9 Simple Profile
- Windows Media Video 9 Main Profile
- Windows Media Video 9 Advanced Profile
- Windows Media Video 9.1 Image
Class Identifier
The class identifier (CLSID) for the Windows Media Video decoder is represented by the constant CLSID_CWMVDecMediaObject. You can create an instance of the video decoder by calling CoCreateInstance.
Interfaces
A video 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).
A video 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 a video decoder behaves as a DMO or an MFT.
| Operating system | Decoder behavior |
|---|---|
| Windows XP | A Windows Media video decoder always behaves as a DMO. |
| Windows Vista and Windows 7 | By default, a Windows Media video decoder behaves as a DMO. If you obtain an IMFTransform interface on a video decoder, it behaves as an MFT. |
Beginning with Windows 7, the Windows Media Video decoder implements the IDMOQualityControl interface.
Input Formats
The following table shows the four-character codes (FOURCCs) that correspond to the categories of encoded input that are supported by the Windows Media Video decoder.
| Category | FOURCC |
|---|---|
| Windows Media Video 9 Simple Profile | "WMV3" |
| Windows Media Video 9 Main Profile | "WMV3" |
| Windows Media Video 9 Advanced Profile | "WVC1" |
| Windows Media Video 9.1 Image | "WMVP" for 9.1, "WVP2" for 9.1 version 2 |
Output Formats
The Windows Media Video decoder supports the following output media subtypes when it is acting as a DMO.
- MEDIASUBTYPE_NV12
- MEDIASUBTYPE_YV12
- MEDIASUBTYPE_YUY2
- MEDIASUBTYPE_UYVY
- MEDIASUBTYPE_YVYU
- MEDIASUBTYPE_NV11
- MEDIASUBTYPE_RGB32
- MEDIASUBTYPE_RGB24
- MEDIASUBTYPE_RGB565
- MEDIASUBTYPE_RGB555
- MEDIASUBTYPE_RGB8
The Windows Media Video decoder supports the following output media subtypes when it is acting as an MFT.
- MFVideoFormat_NV12
- MFVideoFormat_YV12
- MFVideoFormat_YUY2
- MFVideoFormat_UYVY
- MFVideoFormat_YVYU
- MFVideoFormat_NV11
- MFVideoFormat_RGB32
- MFVideoFormat_RGB24
- MFVideoFormat_RGB565
- MFVideoFormat_RGB555
- MFVideoFormat_RGB8
Properties
The Windows Media Video decoder supports the following properties.
| Property | Description |
|---|---|
| MFPKEY_DECODER_DEINTERLACING | Specifies whether the codec decodes interlaced video frames from the compressed stream as progressive frames.
Simple Profile, Main Profile, Advanced Profile. Read/write. |
| MFPKEY_DXVA_ENABLED | Specifies whether the decoder will use DirectX video acceleration hardware, if available.
Simple Profile, Main Profile, Advanced Profile. Write-only. |
| MFPKEY_AVDecVideoSWPowerLevel | Specifies the power level for the decoder.
Simple Profile, Main Profile, Advanced Profile, Image. Read/write. |
| MFPKEY_FI_ENABLED | Specifies whether the decoder should use frame interpolation.
Simple Profile, Main Profile, Advanced Profile, Image. Write-only. |
| MFPKEY_FI_SUPPORTED | Specifies whether the decoder supports frame interpolation.
Simple Profile, Main Profile, Advanced Profile, Image Read-only. |
| MFPKEY_NUMTHREADSDEC | Specifies the number of threads that the decoder will use.
Simple Profile, Main Profile, Advanced Profile, Image. Read/write. |
| MFPKEY_POSTPROCESSMODE | Specifies the post processing mode for the decoder.
Simple Profile, Main Profile, Advanced Profile, Image. Write-only. |
| g_wszWMVCNeedsDrain | Specifies whether the decoder should be drained. Windows 8 Read-only. This property is used by the Windows Media Format runtime. The property type is VARIANT_BOOL. If the value is VARIANT_TRUE, the decoder should be drained after a discontinuity. For more information about draining an MFT, see Basic MFT Processing Model. Note: To query this property, use the IPropertyBag interface. |
Remarks
The maximum resolution allowed by the Windows Media Video 9 decoder is 4096x4096.
Requirements
| Requirement | Value |
|---|---|
| Client |
Windows XP, Windows Vista or Windows 7 |
| Header |
|
| DLL |
|
See also
Feedback
Coming soon: Throughout 2024 we will be phasing out GitHub Issues as the feedback mechanism for content and replacing it with a new feedback system. For more information see: https://aka.ms/ContentUserFeedback.
Submit and view feedback for