FIX: Windows Media Player may buffer for several minutes when a client seeks in multiple bit rate content that is streamed from a Windows Media Services 9 Series server (893069)


The information in this article applies to:

  • Microsoft Windows Media Services 9 Series
Warning This article contains information about editing the namespace. Before you edit the namespace, verify that you have a backup copy that you can restore if a problem occurs. If you edit the namespace incorrectly, you can cause serious problems that may require you to reinstall any product that uses the namespace. Microsoft cannot guarantee that problems that result if you incorrectly edit the namespace can be solved. Edit the namespace at your own risk.

SYMPTOMS

When you stream multiple bit rate (MBR) content from a Microsoft Windows Media Services 9 Series (WMS) server, if the client seeks to a later point in the file from where the client currently is playing, Microsoft Windows Media Player may buffer for several minutes before the video playback resumes. Rich media content does not have this problem.

CAUSE

This issue is typically caused by MBR content that has an embedded script stream. When a seek is issued, the server examines the Index object that is in the header of the ASF file. The server does this to receive the offset to start streaming from. The server starts delivering from the lowest offset as determined by all the selected streams that are in the file. If a script stream is present, the offset is the value of the last script command that was sent. This offset could be lots of time before the time when the client actually seeked. The server delivers the content at a regular speed. Then, the player remains in a buffering state until the time that is on the packets is the same as the seek time. This issue does not occur if the scripts are in the header of the file.

RESOLUTION

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next release that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The following file is available for download from the Microsoft Download Center:

DownloadDownload the WindowsMedia9-KB893069-x86-ENU.exe package now.

For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to obtain Microsoft support files from online services

Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file.

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
   Date         Time   Version     Size       File name
   --------------------------------------------------------
   24-Jan-2005  17:58  9.0.0.3392  2,783,232  Wmsserver.dll
This hotfix is only enabled when the DisableScriptSeek value exists and is set to true. If the node does not exist or is set to the default value, the behavior is the same as before you applied this hotfix.

To add and to change the DisableScriptSeek value, follow these steps:
  1. Stop Windows Media Services. To do this, run the net stop wmserver command at a command prompt.
  2. Change to the directory where the namespace file is located. By default, this file is located in the %SystemRoot%\system32\windows media\server directory.
  3. Open the ServerNamespace.xml file in a text editor such as Notepad.
  4. Locate the Other node in the namespace.
  5. Add the following node under the Other node.
    <node name="ASFMediaParser" opcode="create" >
  6. Under the ASFMediaParser node, add the following node.
    <node name="DisableScriptSeek" opcode="create" type="boolean" value="true" />
  7. Close out the ASFMediaParser node by adding the following node.
    </node> <!-- ASFMediaParser -->
  8. Save and then close the ServerNamespace.xml file.
  9. Start Windows Media Services. To do this, run the net start wmserver command at a command prompt.
The following is another representation of the changes to the ServerNamespace.xml file.
 <node name="Other" opcode="create" >
     <node name="Client Upgrade" opcode="create" >
           ...
     </node> <!-- Client Upgrade -->

     <node name="ASFMediaParser" opcode="create" >
          <node name="DisableScriptSeek" opcode="create" type="boolean" value="true" />
     </node> <!-- ASFMediaParser -->
 </node> <!-- Other -->

STATUS

Microsoft has confirmed that this is a bug in the Microsoft products that are listed in the "Applies to" section.

MORE INFORMATION

Besides fixing the server issue that is described in this article, we recommend that you download and then install Microsoft Windows Media Player hotfix 892313 to address a related script command issue.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

892313 FIX: Updates for Windows Media Player 9 Series and for Windows Media Player 10

Modification Type:MinorLast Reviewed:10/7/2005
Keywords:kbBug kbfix KB893069 kbAudDeveloper kbAudITPRO
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