Understanding How Windows Media Rights Manager Works

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Understanding How Windows Media Rights Manager Works

This section provides information about using the Windows Media Rights Manager SDK to deliver protected Windows Media files, which involves packaging Windows Media files, and issuing and generating licenses. A packaged file is encrypted with a key (a piece of data that locks and unlocks the content). To play a packaged Windows Media file, consumers must obtain a separate license containing the key. You can deliver a license in several ways. For example, a license can be delivered with the Windows Media file, or it can be delivered after a consumer provides additional information.

Note   The Windows Media Encoder 9 Series SDK provides an alternate way to package files. The only way to stream live protected content is by using an application based on that technology. However, to issues licenses for those files, you must still use the Windows Media Rights Manager SDK.

The license for a Windows Media file is linked to the computer or device to which it is issued. Consumers can share Windows Media files but each recipient must have a separate license to play them. In addition to unlocking Windows Media files, licenses contain rights and other properties that specify the use of the Windows Media file. For example, the license determines the number of times a Windows Media file can be played, if it can be transferred to a portable device, if the license expires, and the minimum security level that is required of the playback device. The properties are configured in the license, separate from the Windows Media file, letting you issue different licenses for the same Windows Media file and change license properties on the fly. For example, to promote a song, you can distribute a Windows Media file to an electronic mailing list with a license that enables consumers to play the Windows Media file ten times. When consumers purchase the song, you can issue a new license with the right to unlimited playback.

The following diagram shows the basic process for delivering packaged Windows Media files and issuing licenses.

The process flow of Windows Media Rights Manager

  • The content owner creates digital files and encodes them into Windows Media Format with .asf, .wma, or .wmv file name extensions.
  • The content packager packages Windows Media files.
  • The content distributor delivers packaged Windows Media files to consumers.
  • The license issuer issues licenses for Windows Media files, either before a Windows Media file is played, or in response to a license request by a consumer's player.
  • Consumers play packaged Windows Media files. If a license is not found for the Windows Media file, the player requests a license.

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