Setting up an MBR stream

If you plan to deliver your content as a unicast stream from a server running Microsoft Windows Media Services, encoding multiple-bit-rate (MBR) stream provides users with better quality content during times of network congestion. When you set up an MBR stream, your content is encoded at each bit rate that you specify. When a player receives an MBR stream, only the stream that is the most appropriate for current network conditions plays. The Windows Media server and player handle the process of selecting the appropriate stream, which is invisible to the user. Because an MBR stream is intended for use only in a streaming scenario, you can only use CBR encoding when encoding an MBR stream.

You can encode an MBR stream for both audio and video content; however, it is not necessary to use MBR encoding for both audio and video in a stream. For example, you can stream audio at one bit rate and have multiple bit rates for the video portion of the stream.

When setting up an MBR stream, keep in mind that the more bit rates you select, the larger the aggregate bandwidth for live stream distribution from the encoder to a Windows Media server is required. To estimate the aggregate bandwidth of an MBR profile, calculate the sum of each audio and video bit rate, and the script bit rate. Also keep in mind that encoding an MBR stream uses more processing power for the encoding computer.

If you are using the Windows Media Audio 9 Voice codec in an MBR session and you specify the mixed voice and music mode, it is recommended that you do not include any bit rates below 8 kilobits per second (Kbps) in the session. The reason for this is that any bit rates below 8 Kbps will be encoded in voice-only mode, which may result in suboptimal quality in your audio content.

Related topics

• Customizing a session
• To encode an MBR stream
• To encode single-bit rate audio with MBR video
• To encode single-bit rate video with MBR audio