File Name Extensions
[The feature associated with this page, Windows Media Player SDK, is a legacy feature. It has been superseded by MediaPlayer. MediaPlayer has been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer instead of Windows Media Player SDK, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]
There are specific guidelines for the use of file name extensions for Windows Media metafiles. Windows Media metafile name extensions are used to identify the different types of Windows Media files. A file name extension provides an Independent Software Vendor (ISV) with information about the rendering requirements of an application that uses a particular extension, and enables content authors to target general types of media players.
The file name extension guidelines are listed in the following table. It is recommended that a file's MIME type, located in the file header, be used for file-type identification.
| File name extension | MIME type | File content |
|---|---|---|
| .wma | audio/x-ms-wma | Windows Media file with audio content only. Typically used to download and play files or to stream content. |
| .wmv | video/x-ms-wmv | Windows Media file with audio and/or video content. Typically used to download and play files or to stream content. |
| .asf | video/x-ms-asf | Legacy content. Typically used to download and play files or to stream content. May contain audio and/or video content. Typically used to download and play files or to stream content. |
| .wm | video/x-ms-wm | Reserved |
| .wax | audio/x-ms-wax | Metafiles that reference Windows Media files with .asf, .wma, or .wax file name extensions. |
| .wvx | video/x-ms-wvx | Metafiles that reference Windows Media files with .wma, .wmv, .wvx, or .wax file name extensions. |
| .asx | video/x-ms-asf | Metafiles that reference Windows Media files with .wma, .wax, .wmv, .wvx, .asf, or .asx file name extensions. |
| .wmx | video/x-ms-wvx | Reserved. |
Remarks
Scripting and digital rights management (DRM) must be supported by any application that renders Windows Media files.
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