Using the Windows Media Video 9 Advanced Profile Codec
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The basic video procedures described in the Working with Video section also apply directly to the Windows Media Video 9 Advanced Profile codec. No special procedures are required.
The Windows Media Video 9 Advanced Profile encoder object is associated with the class identifier CLSID_CWMV9EncMediaObject, and the decoder with the class identifier CLSID_CWMVDecMediaObject. The FOURCC value for media types using this codec is "WVC1".
The Windows Media Video 9 Advanced Profile codec supports all common encoding modes as well interlaced encoding, mixed interlaced and progressive encoding, resolutions that are different than the display, and range reduction features. Another feature is the ability to store sequence and frame metadata in the bit-stream itself; previously this had required use of the ASF and Data Unit Extensions API.
The following properties of the Windows Media Video 9 Advanced Profile codec, which can be controlled using registry settings, do not have corresponding IPropertyBag or IPropertyStore strings:
- Dquant Option.
- Dquant Strength.
- Force Overlap.
- Motion Vector Cost Method.
Achieving Optimal Visual Quality
To achieve optimal visual quality using the Windows Media Video 9 Advanced Profile encoder for most video data you can set the MFPKEY_COMPRESSIONOPTIMIZATIONTYPE property to 1.
About the Previous Windows Media Video 9 Advanced Profile Codecs
The current version of the Windows Media Video 9 Advanced Profile codec is based on the Society of Motion Picture and Television Engineers (SMPTE) standard for VC-1 (SMPTE 421M) Advanced Profile. This codec replaces the earlier codec from Windows also called the Windows Media Video 9 Advanced Profile codec which was identified by the FOURCC code "WMVA". The previous version of the VC-1 codec was implemented before the VC-1 advanced profile standard was finalized, and is no longer supported.
See Also