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Windows Media Audio 10 Professional Codec

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The Windows Media Audio 10 Professional encoder object is instantiated using the class identifier CLSID_CWMAEncMediaObject. The decoder objects are instantiated using the class identifier CLSID_CWMADecMediaObject, or CLSID_CWMAudioSpdTxDMO for decoding Sony/Philips Digital Interconnect Format (S/PDIF). Windows Media Audio 10 Professional encoded content is identified by the audio tag 0x162.

Encoder Properties

The Windows Media Audio 10 Professional encoder supports the properties of the Windows Media Audio 9 encoder. See the list at Windows Media Audio 9 Codec.

Decoder Properties

In addition to the Windows Media Audio 9 decoder properties, the Windows Media Audio 10 Professional decoder supports the following properties.

Property Description
MFPKEY_WMADEC_DRCMODE Specifies the dynamic range control mode that the audio decoder will use.
MFPKEY_WMADEC_FOLDDOWN_MATRIX Specifies the author-supplied fold-down coefficients for decoding multichannel audio for fewer channels than the encoded stream contains.
MFPKEY_WMADEC_HIRESOUTPUT Specifies whether the audio decoder should deliver high-resolution output.
MFPKEY_WMADEC_LTRTOUTPUT Specifies whether the audio decoder should perform Lt-Rt fold down.
MFPKEY_WMADEC_SPKRCFG Specifies the speaker configuration on the client computer.
MFPKEY_WMADRC_AVGREF Specifies the average volume level of audio content.
MFPKEY_WMADRC_AVGTARGET Specifies the desired average volume level of output audio content.
MFPKEY_WMADRC_PEAKREF Specifies the highest volume level occurring in audio content.
MFPKEY_WMADRC_PEAKTARGET Specifies the desired maximum volume level of output audio content.

Remarks

An audio encoder or decoder object exposes the IMediaObject interface so that the object can be used as a DirectX Media Object (DMO), and the IMFTransform interface so that the object can be used as a Media Foundation Transform (MFT).

A Windows Media Audio 10 Professional encoder or 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 Audio 10 Professional encoder or decoder behaves as a DMO or an MFT.

Operating system Encoder or decoder behavior
Windows XP A Windows Media Audio 10 Professional encoder or decoder always behaves as a DMO.
Windows Vista By default, a Windows Media Audio 10 Professional encoder or decoder behaves as a DMO. If you obtain an IMFTransform interface or an IPropertyStore interface on an Audio 10 Professional encoder or decoder, it behaves as an MFT.
Windows 7 By default, a Windows mMedia Audio 10 Profesional encoder or decoder behaves as a DMO. If you obtain an IMFTransform interface on an Audio 10 Professional encoder or decoder, it behaves as an MFT.

Requirements

Client: Requires Windows 7, Windows Vista, or Windows XP.

Header: Include wmcodecdsp.h.

Library: Use wmadmoe.dll for the encoder or wmadmod.dll for the decoder (wmadmod.dll for decoding S/PDIF format).

See Also