There are several versions of Windows Media digital rights management (DRM). DRM version 1 is often set apart from the other versions in this documentation, because it is implemented using techniques that are different from the later versions. The second generation of Windows Media DRM is called DRM version 7 because it was introduced as part of the Windows Media Format 7 SDK. It is sometimes called DRM version 2. The later versions of Windows Media DRM, DRM version 9 and the new Windows Media DRM 10, are extensions of DRM version 7 and use the same procedures for implementation. All versions of Windows Media DRM use the same encryption routines; the differences between versions have to do with license features.
When you create protected files by using the objects of the Windows Media Format SDK, you should support both version 1 and the most current version. Files protected by DRM version 1 differ from files protected by later versions only in the contents of the header. Newer files that contain the additional header information can still be used on clients that render only version 1 content. While later versions of DRM offer a higher level of security and additional features, there are still many players that use only version 1.
For more information on DRM versions, see the Windows Media Rights Manager SDK documentation.
DRM is not supported by the x64-based version of this SDK.