Multicasting Live ASF Streams

Use the following steps when creating a program that multicasts live ASF streams generated by the Real-Time Encoder.

The illustration shows the Real-Time Encoder, NetShow Server, and HTTP server on separate computers. While all software can run on a single computer, in most cases you should run the system as shown. Because the Real-Time Encoder places heavy demands on the processor, dedicating a computer to run it can ensure performance. If you plan to use NetShow Server's unicast HTTP streaming, you must run your HTTP server on a separate computer.

1. On the computer used to run the NetShow Real-Time Encoder, connect the audio or video source to the appropriate input on the server's sound or video card.
2. Set up the Real-Time Encoder to process the stream for the multicast. You can either use one of the default stream formats, or create one. If you create a format, save it as an Active Streaming description file (.asd).

   The stream format includes information such as the types of media in the stream, for example, sound and URLs, and the codec used to compress the stream. NetShow uses this information when creating a channel for the stream.

   For more information, see the NetShow Tools Guide.

3. On the NetShow server, start NetShow Administrator, connect to the server you want to manage, and then use Configure Channels to create a channel for the stream.

   The channel includes the IP address and port on which the stream is multicast, the stream format used on the channel, and the network location where clients can obtain the channel information. To specify the stream format, reference the .asd file for the stream.

   For more information, see Creating a Channel.

4. Using Configure Channels, export the channel to a location on the network where clients can reach it, and save it as a NetShow channel file (.nsc). For example, if you are multicasting over a LAN to clients running the stand-alone NetShow Player, you can store the file in a public directory. If you are multicasting over an intranet or the Internet to clients running NetShow Player embedded in a Web page, export the file to a publishing point on the HTTP server.

   For more information, see Exporting a Channel.

5. In NetShow Administrator, use Manage Programs to create a program.

   Add the stream to the program by specifying the channel you created and the stream's source. Specify the stream source using either a URL to point to the computer running the Real-Time Encoder, or using the alias you created when defining the stream format using the Real-Time Encoder.

   To specify a URL, use the MSBD protocol, the name of the server running the Real-Time Encoder, and, optionally, the port:
   msbd://servername:portnumber

   It is necessary to specify a port only when you have changed the default port used by the Real-Time Encoder.

   For more information, see Creating a Program and Adding Active Streaming Media to a Program.

6. In NetShow Administrator, use Manage Programs to create an announcement for the program.

   Clients use the announcement to locate the .nsc file that supplies channel information for the program. Announcements are saved as .asx files. After you have created an announcement, you can distribute it in a variety of ways: store it on the HTTP server in a publishing point where clients using the embedded player or stand-alone player can access the file through a Web page; store it in a public directory on a LAN where clients using the stand-alone player can open it; or distribute it through e-mail to clients using the stand-alone player.

   For more information, see Creating a Program Announcement.

7. To begin the multicast, start feeding the source stream, start the Real-time Encoder and, using Manage Programs, start the program.

   For more information, see Starting and Stopping a Program.

8. Clients can now listen to the multicast using either the stand-alone or embedded NetShow Player. To receive the multicast using the stand-alone player, specify the .asx file. To set up the embedded player to receive the multicast, specify the .asx file in either the object information or the scripting code for the control.

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