Sourcing from an encoder

When an encoder is providing a stream for a broadcast, it can either push the stream to the server or the server can pull it from the encoder. When pushing a stream, the encoder initiates the connection with the server; on the other hand, when pulling the stream from the encoder, the server initiates the connection. The decision whether to push or pull depends upon your situation.

Pushing the stream from the encoder is useful if the encoder is behind a firewall or if the encoder administrator needs to be in control of the broadcast. For information on how to configure your server to broadcast content from an encoder, see To broadcast content pushed from an encoder.

Pulling the stream from the encoder is useful in several scenarios. First, if there are multiple distribution servers, all connecting at different times, each server can initiate the connection when it is ready to stream. In addition, pulling a stream from a server is useful if you need to minimize bandwidth usage between the server and encoder. For example, the server administrator can add a publishing point and configure it to start automatically, which means that the server doesn't initiate the connection with the encoder until the first client connects. This eliminates unnecessary bandwidth use between the server and the encoder. Pulling from the server is also useful when the server is behind a firewall.

Whether you decide to use push or pull to receive the stream from the encoder, the following rules apply:

• Encoder streams are broadcast content. When the encoder pushes a stream through the server it must use a broadcast publishing point. If you are pulling the stream from an encoder you can use either an on-demand or a broadcast publishing point, but the user experience will not change. The content is still treated as a broadcast and users cannot control the content — they cannot fast-forward, rewind, seek or pause regardless of whether they connect to an on-demand or broadcast publishing point.
• The encoder and the server connect using Hypertext Transfer Protocol (HTTP). HTTP is used to transmit a stream between an encoder and a Windows Media server in order to enable communication through firewalls. If the encoder is pushing the content, the HTTP server control must be enabled in order for the encoder to successfully connect to the server. If you are pulling the stream, set the publishing point path to reference the URL of the encoder from which you want to stream content, such as http://encodername:port. To verify that you have the correct URL and that the encoder is broadcasting, open the encoder URL in Windows Media Player. The Player should render the stream from the encoder.
• Using redundant encoders increases the reliability of the source content. You can configure Windows Media Services to switch from one encoder to another if the primary encoder fails.

To receive the content, users type the URL of the publishing point in their players; for example, mms://servername/publishing_point_name.

Related topics

• About publishing point types
• Announcing content
• Sourcing from playlists, files, and encoders
• To access the Add Publishing Point Wizard
• To add a publishing point using the advanced method
• To broadcast a stream pulled from an encoder
• To enable content rollover in case of encoder failure