Windows Media Services supports wrappers, which are Windows
Media metafiles that can be used to direct users to certain
additional content before the requested content and then to an
additional piece of content once the requested content ends.
Wrappers are especially useful in the following situations:
Broadcast content. During a broadcast, users can connect
at different times, making it difficult to ensure that a piece of
content (such as an advertisement, station identification, or
copyright notice) is received by every user. However, when a
wrapper playlist is used in conjunction with the broadcast, the
content in the first part of the wrapper is streamed to the user
regardless of the point at which he or she connects to the
broadcast. This makes it possible to ensure that a piece of content
is received by every user who connects to your broadcast.
On-demand content. Wrappers are also an efficient way to
play content, such as advertisements, to every user who connects to
your server. Each publishing point on your server can use the same
wrapper, so you only need to update one file when changes
occur.
