L

latency

The delay that occurs while data is processed or delivered.

letterbox

A video display format in which black bars appear above and below the video image while it is played. The letterbox format maintains the original aspect ratio of an image when it is displayed in a window with a different aspect ratio.

license

Data attached to protected content that describes how the content can be used.

license acquisition

The process of obtaining a license to play a packaged Windows Media file. The player attempts to obtain a license from a license acquisition URL, which is specified in the Windows Media file.

license acquisition URL

The URL that points to the first Web page that appears in the license acquisition process. A license acquisition URL is included in each packaged Windows Media file; when a consumer tries to play a Windows Media file that is not licensed, the player opens the license acquisition URL to acquire a license.

license issuer

The person or organization that uses the Windows Media Rights Manager SDK to issue licenses for packaged Windows Media files, for example, a license clearing house.

license key seed

A shared secret value that is used to generate keys to encrypt Windows Media files.

license management

A feature of the Windows Media Rights Manager SDK that enables consumers to back up the licenses for their Windows Media files and restore them to the same computer or to different computers. The restoration process is managed by Microsoft License Management Service, which limits the number of times a license can be restored to prevent fraud.

license store

An area on a computer where licenses are stored.

licensed file

A Windows Media file that has an associated license restricting the playing of that file. The restrictions stated in the license vary depending on the license creator.

licensing server

A computer that runs Windows Media License Service and issues licenses.

load balancing

A technique used for scaling the performance of a server-based program by distributing client requests across multiple servers.

log

To record actions that take place on a computer.

loop

To repeat a stream continuously.

lossless compression

A process for compressing data in which information is arranged in a more concise form and restored to its original state upon decompression.

lossy compression

A process for compressing data in which information deemed unnecessary is removed and cannot be recovered upon decompression. Typically used with audio and visual data in which a slight degradation of quality is acceptable.