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Consider the following scenario:
On a multiprocessor system, you encode a video by using one of the following:
Windows Media Encoder 9 Series
An application that is based on the Windows Media Format SDK
You compress the video by using one of the following:
The Windows Media Video v9 codec
The Windows Media Video 9 Advanced Profile codec
In this scenario, the WMV9 encoder performance is severely impaired.
This behavior is due to a bug in the Windows Media Video v9 encoder DirectX Media Object (DMO). The encoder sets an affinity for multiple instances of the DMO to the same single-processor core when the multiple instances are instantiated by the same caller thread.
A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that is described in this article. Apply it only to systems that are experiencing this specific problem.
To resolve this problem, obtain the hotfix from the Microsoft Download Center.
The following files are available for download from the MicrosoftDownload Center.
Note This hotfix does not have a 64-bit version for Windows XP. This package installs the 32-bit version of this hotfix on the 64-bit version of Windows XP.
For more 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
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The global 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 item in Control Panel.
Microsoft has confirmed that this is a bug in the Microsoft products that are listed in the "Applies to" section.
Steps to reproduce the problem
Install Windows Media Encoder 9 Series on a multiprocessor computer.
Configure the encoder to encode a multi-bitrate video.
Use a file as a source.
In Performance Monitor, notice that only one CPU is near 100 percent.