Packaging Windows Media Files

Packaged Windows Media files are files that have been protected by using Windows Media Rights Manager. Before packaging digital files, you must encode them into Windows Media Format with .asf, .wma, or .wmv file name extensions.

The packaging process includes generating or specifying a key , generating and signing the content header , and then encrypting the Windows Media file with this information. A secret value, or license key seed, is used to generate the key, and the key is used to encrypt the Windows Media file. After the Windows Media file is packaged, it is distributed to consumers.

The content header of a packaged Windows Media file contains the following information:

• Key ID
• Content ID (optional, but recommended)
• License acquisition URL
• Additional metadata (optional)
• Uplink ID (optional, for license chains)

The content packager can require the consumer to use a player that has received a security upgrade (which individualizes the player), and add information to the content header to identify the content owner , the content distributor , and so forth. This information can be used by the license issuer .

See Also

• Licensing Packaged Files
• Playing Packaged Windows Media Files
• Understanding How Windows Media Rights Manager Works