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SDK and License Versions
The Windows Media Rights Manager SDK has had four major releases, and each version has added features to the basic functionality for protecting and licensing content. The table below summarizes the main feature additions for each version of the Windows Media Rights Manager SDK. Each version corresponds to a release of the Windows Media Format SDK and Windows Media Player.
| SDK and license version | Features | Based on |
| 1 | Basic rights and license delivery
(Macintosh supports only v1. Licenses from later versions of the Windows Media Rights Manager SDK can include v1 information for older players and/or Macintosh players.) |
Windows Media Player 6.4
Windows Media Format SDK 4 |
| 7 | Security features (security levels, SAP)
Individualization New rights (counted actions, expiration) Custom metadata Silent license delivery and predelivery |
Windows Media Player 7
Windows Media Format 7 SDK |
| 9 | Live streaming of protected content
Integration with Windows Media Encoder Signed content header |
Windows Media Player 9 Series
Windows Media Format 9 Series SDK |
| 10 | Metering
License revocation License chains Output protection levels New rights (collaborative play, playlist burning, updated support for devices) |
Windows Media Player 10
Windows Media Format 9.5 SDK |
Note The same encryption has been used for every release.
The release of Windows Media Rights Manager 7 included significant changes in the way content was protected and licensed, so that licenses fall into two categories: version 1, or version 7 and later. Sometimes references are made to version 2 licenses (for example, in comments in code samples, and in some parts of the API), though version 2 and version 7 are two names for the same version.
Knowing the differences between the license versions is important because it impacts your consumers and determines who can play your protected content. For example, some consumers are still using media players that support only version 1, including Macintosh users. However, media players based on Windows Media Format 7 SDK and later are backward compatible with version 7 and later licenses. In other words, a version 9 player can interpret a version 10 license, though a version 1 player cannot—to support a version 1 player, you must issue a separate version 1 license. The Windows Media Rights Manager API lets you include version 1 information when protecting content so that you can implement a process to issue either version 1 or version 7 and later licenses, depending on the player that attempts to play the content. However, version 1 licenses do not support the security features that are available in version 7 and later, so license issuers may choose to not support version 1 and instead ask their customers to upgrade their media players.
Although older players can interpret newer licenses, all newer features are not necessarily supported. For example, version 10 licenses support metering and license chains, but version 7 and 9 players do not support these features. When receiving a license request, license issuers can determine the client version and then issue a license accordingly. For example, the license issuer might issue a more restrictive license to earlier version players.
Prior to the version 10 release of the Windows Media platform, content and licenses that were transferred to portable devices were using version 1 licenses. These devices were based on Windows Media DRM for Portable Devices version 1, and supported basic rights and features. Now, with the version 10 release of the Windows Media platform, devices based on Windows Media DRM 10 for Portable Devices are more secure and can support all new features, such as metering, secure clock and expiration, and license chains for faster license synchronization.
See Also