Alternate between live and
prerecorded content in your broadcast
This quick start demonstrates how to use Windows Media Services
to stream both live and prerecorded (stored) content. Despite the
inclusion of stored content, users do not have the ability to
pause, fast-forward, or rewind the broadcast. The user has the
option of starting, stopping, and resuming the broadcast stream,
creating a user experience similar to tuning in to a radio or
television broadcast.
This quick start is an example of how versatile server-side
playlists can be and how they are used to manipulate the playback
at the client computer. For this task, you must be streaming live
content from a computer running an encoder and you must have
prerecorded content, such as an advertisement, in a Windows Media
file. In the following procedure, the client receives five minutes
of live content, which is then is interrupted for an advertisement.
When the advertisement ends, the live content resumes for another
five minutes.
In Windows Media Services, in the console tree, click
Publishing Points. In the details pane, click the View
playlist editor button. The Windows Media Playlist Editor
opens.
Add container elements to the playlist to control how different
playlist elements are played back with respect to each other. In
this quick start, the publishing point will pause the content when
one element interrupts another. To specify this behavior do the
following:
In the Windows Media Playlist Editor, click the Add
element arrow on the toolbar and then click Exclusive.
An excl element appears in the playlist tree.
Click the excl element that you just created. Click the
Add element arrow on the toolbar and then click
PriorityClass. A priorityClass element appears in the
below the excl element.
Click the priorityClass element that you just created.
In the properties area, click the peers attribute and then
type Pause in the text box. Press ENTER. This setting
instructs the publishing point to pause this content whenever it
switches to another media element.
Add live content to the playlist by doing the following:
In the Windows Media Playlist Editor, click the Add
element button on the toolbar. The Add Media Elements
dialog box appears.
Type the URL of the encoder stream by using the following
syntax: http://encoder_name:port. Select the Add as a
child element check box and then click OK. The
media element appears in the playlist tree beneath the
priorityClass element and displays the URL of the
encoder.
In the Windows Media Playlist Editor, set the following values
to define how the live content should be played back. In this
example, the content will start immediately and stream for 10
minutes:
In the playlist tree, click the media element that you
added in the previous step.
Click the begin attribute in the properties area and
then type 0 in the text box. Press ENTER. This setting
instructs the publishing point to begin streaming the live content
as soon as the publishing point starts.
Click the dur attribute in the properties area and then
type 10min in the text box. Press ENTER. This setting
instructs the publishing point to stream the live content for a
total of 10 minutes.
To provide a unique identifier for the live content, click the
id attribute in the properties area and then type a name for
the media element, such as M1, in the text box. Press
ENTER. This setting provides this media element with a name
that can be referenced by other elements in the playlist.
Add prerecorded content to the playlist by performing the
following steps. In this example, the prerecorded content is an
advertisement:
In Windows Media Playlist Editor, click the
priorityClass element in the playlist tree.
Click the Add element button on the toolbar. The Add
Media Elements dialog box appears.
Type the name and location of the advertisement that you want
to add. Select the Add as a child element check box and then
click OK.
Define how the advertisement should be played back by doing the
following. In this example, the advertisement starts five minutes
after the content starts:
In the playlist tree, click the advertisement media
element that you just added.
Click the begin attribute in the properties area and
then type M1.begin + 5min, for example, in the text box.
Press ENTER. This instructs the publishing point to wait until the
live content has played for five minutes and then play the
advertisement.
Provide a unique identifier for the advertisement by clicking
the id attribute in the properties area. Type a name for the
advertisement, such as M2, in the text box. Press ENTER.
This provides this media element with a name that can be
referenced by other elements in the playlist.
Save the playlist and then close the Windows Media Playlist
Editor.
Use the Add Publishing Point Wizard to create a new broadcast
publishing point by doing the following:
On the Action menu, click Add Publishing Point
(Wizard). The Add Publishing Point Wizard appears.
On the welcome page, click Next.
On the Publishing Point Name page, type a name for the
new publishing point.
On the Content Type page, click Playlist.
On the Publishing Point Type page, click Broadcast
Publishing Point.
On the Delivery Options for Broadcast Publishing Points
page, click Unicast.
Use the wizard to reference the playlist that you created in
steps 1 through 9 by using the following settings:
On the File Location page, click Existing
playlist. In File name, type the name and location of
the new playlist.
On the Unicast Logging page, select the check box if you
want to log data about your clients.
On the Publishing Point Summary page, verify that the
settings for the new publishing point are correct.
On the Completing the Add Publishing Point Wizard page,
clear all of the check boxes, and then click Finish.
Configure the following publishing point settings to have the
publishing point start when the first client connects:
In the console tree, click the publishing point you just
created. In the details pane, click the Properties tab. In
Category, click General.
Click the Start publishing point when first client
connects property and then click the Enable button.
Users can now receive the content in the playlist by typing the
URL of your publishing point in their player. The URL to a
publishing point uses the following syntax: connection
protocol://server_name/publishing_point_name (for example,
mms://server1/my publishing point).
For more information about testing your streaming content, see
Testing a stream.
