Microsoft KB Archive/940174

= The video occasionally is rebuffered, or frames are dropped when you try to stream a video through a multicast from Windows Media Services to Windows Media Player clients =

Article ID: 940174

Article Last Modified on 8/15/2007

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APPLIES TO


 * Microsoft Windows Media Services 9 Series

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SYMPTOMS
When you try to stream a video through a multicast from Microsoft Windows Media Services to Microsoft Windows Media Player clients, the video occasionally is rebuffered. Or, frames are dropped.



CAUSE
Typically, the network hardware can handle the way that Windows Media Services delivers packets on the network. However, in certain scenarios, the network hardware cannot handle the brief spikes in bandwidth that Windows Media Services delivers on the network. Therefore, the network hardware loses the packets that Windows Media Services delivers.



WORKAROUND
To work around this behavior, follow these steps:  In the ServerNamespace.xml file, set the value of the TCPBurstLimitMS node to 0, and then set the value of the UDPBurstLimitMS node to 0.

Note When you set these values, Windows Media Services sends the data in the buffer after Windows Media Services receives new packets. Additionally, Windows Media Services does not send multiple packets at the same time.

For more information about how to set these values, click the following article number to view the article in the Microsoft Knowledge Base:

828566 Windows Media Services 9 Series network send behavior may lead to an unwanted client experience

 In Microsoft Windows Media Encoder, set the maximum packet size. To determine the appropriate maximum packet size, use the table that appears after these steps.

Note The maximum packet size is based on the audio part of the stream. The maximum packet size reduces the size of the audio packets or of the video packets that are sent to the server that is running Windows Media Services. This setting makes the encoder slightly less efficient. However, the decrease in efficiency is not noticeable. Enable Forward Error Correction (FEC), and then set the value to 24.

Note This FEC value increases the Windows Media Player clients' tolerance for packet loss. But, this FEC value adds overhead to the stream. You can try to set the value to a number that is less than 24. The FEC value sets the range of packets for which a single packet can provide parity information. A lower FEC value increases the parity, and a lower FEC value also increases the overhead. In Windows Media Services, disable buffering on the server. To do this, follow these steps:  Start the Windows Media Services Microsoft Management Console (MMC) snap-in, or start Windows Media Services Administrator for the Web. Click the broadcast publishing point. In the details pane, click the Properties tab.</li> In the Category pane, click Networking.</li> In the Property pane, click Enable buffering, and then click Properties.</li> In the Enable Buffering Properties dialog box, click Disable buffering.</li></ol> </li></ol>

To determine the maximum packet size to use in step 2, use the following table.

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STATUS
This behavior is by design.

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MORE INFORMATION
For more information about Windows Media Services 9 Series, visit the following Microsoft Web site:

http://www.microsoft.com/windows/windowsmedia/howto/articles/introhosting.aspx

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