• Article
Windows Media Rights Manager SDK banner art

Streaming Secure Files

You can provide music and video to your consumers in different ways. In addition to letting consumers download digital media files, you can also stream them. Streaming content is a good choice when you want to make it available but you do not want to give copies of it to consumers. Streaming also forces consumers back to your Web site to play your digital media files, which is advantageous when you want to make sure that consumers see branding, advertisements, and other information on your site.

However, streaming digital media files rather than providing them for download does not necessarily ensure that the files are secure. Several programs are currently available that allow a consumer to capture an audio or video stream and save it to a file on their computer. Consumers can then play the resulting digital media file at any time and share it with other people. To ensure that your audio and video content is secure and protected, package your digital media files first, and then stream them.

Streaming packaged files provides several solutions to ensure security:

  • If consumers save streamed files to their computer, the file remains protected; that is, consumers must have a license to play the saved stream.
  • Because a license is required to play a packaged file, even if consumers share a saved stream with others, those people cannot play the file without first obtaining a license.
  • You can provide a URL in the packaged file so that when consumers try to play a local copy of it and do not have a license, they are redirected to a Web site from which they can obtain a license. For example, you might display a page with information about the particular song or video, or redirect consumers to a location from which the file can be streamed again.

After packaging your files, you can set up your Web site to stream them and to deliver licenses for them. You must consider how you want to issue licenses, what rights you want to allow, and also which URL to display if a consumer saves a streamed file and then tries to play it.

This SDK provides many methods for issuing licenses, but perhaps the best way for a streamed file is to predeliver a license; that is, to issue the license after a consumer selects the digital media file they want to play, but before it is streamed. For example, a consumer selects a song to play, you issue a license, and then stream the song. A predelivered license provides the best experience for consumers because they are not aware of the licensing process; users simply select a file that is then streamed to their players.

You must also consider the rights you want to allow for your packaged digital media files. For streaming files, you should allow the right to play the file. Because consumers can save the stream to their computer, you might limit the rights you allow. For example, you might allow only one playback, which is the minimum right consumers need to play a stream. If consumers save the stream and try to play the resulting file on their computer, the license does not allow further playback.

After you have established a delivery method and set the rights for a file, you should specify a license acquisition URL to display when consumers try to play a packaged file for which there is no valid license (or when they try to play a saved stream with a license that does not allow further playback). This URL typically displays a Web site where the consumer can acquire a license. However, for streamed files, you might specify a URL that points to a registration page on your Web site. Or you might display a page with information that tells consumers that they cannot play a local copy of your digital media stream and must instead play it from your Web site.

The following packaging and licensing configuration is one possibility for streaming.

Packaging

  • Encrypt all of your digital media files, regardless of whether you stream them or provide them for download.
  • Set the license acquisition URL in each content header to a page that is worded specifically for undesired stream captures. When the consumer plays a captured stream and does not have a valid license, this URL is displayed. Inform the consumer that they must return to your Web site to play this item and cannot play a saved copy of it. The saved stream is not playable and essentially rendered useless.

Licensing

  • If the consumer's computer supports it, require Secure Audio Path in the license (set the corresponding property).
  • If the consumer is using a player that supports the Windows Media Rights Manager SDK, before streaming the digital media file, predeliver a license that allows one play.

See Also