Enabling Windows Media DRM in Mobile Media Scenarios

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Enabling Windows Media DRM in Mobile Media Scenarios

You can integrate Windows Media Digital Rights Management (DRM) 10 into your mobile media solution to protect streaming and downloadable content. In most cases, Windows Media DRM helps to assure that audio and video content can only be played by mobile service subscribers who have been successfully billed.

Protecting Mobile Content: The Basics

When content is encoded, the data is encrypted with a key, which is then required to decrypt and play the content. The key is contained in a license that is obtained by a device when approval to play the content has been granted. When a license is delivered, it combines device-specific information with the key, so that the licensed media will play only on the device to which it was authorized.

There are two ways that mobile service subscribers can obtain licenses for DRM-protected content:

Direct License Acquisition (DLA). When subscribers download content directly to their devices, DLA is used, and the devices obtain the licenses from a license server.
Indirect License Acquisition (ILA). When subscribers transfer licensed content from personal computers to their devices, ILA is used, and the devices obtain the licenses from the personal computers.

You can also implement a dual-delivery model in which a subscriber is granted a license to both a mobile-optimized version of the content that is delivered directly to the handset and a high-fidelity version that is delivered to the subscriber's personal computer within a single transaction.

Purchase, Subscription, and Rental Scenarios

Within a transaction scenario, you can set an expiration time, limit the number of plays for a title, or both. Windows Media DRM enables three types of scenarios for licensing content:

Purchase. A purchase transaction covers the purchase of specific music or movie files, and takes place after the content has been selected. Typically, subscribers search, select, and purchase music tracks using their mobile devices. After the transaction is approved, the music and licenses are downloaded to the devices.
Subscription. A subscription transaction covers the acquisition of unspecified music or movie files, and takes place prior to the content being selected. A subscription is often limited by time or by the number of downloads. For example, subscribers could download an unlimited number of music files in one month.
Rental. A rental transaction covers the rental or preview of specific music or movie files. An expiration time of one day is set for the license; after the license expires, the subscriber can choose to purchase the title, and will then receive a license that has no expiration time and no limits on the number of plays.

For More Information

For more information about protecting content, see Windows Media DRM 10.
For more information about creating a subscription service, see Creating a Windows Media Player 10 Subscription Online Store.
To download white papers about Windows Media DRM 10 device technologies, see A General Overview of Windows Media DRM 10 Device Technologies and A Technical Overview of Windows Media DRM 10 for Devices.