FIX: Windows Media Player 11 cannot play WMV files that contain multiple video streams

Microsoft Windows Media Player 11 cannot play Windows Media Video (WMV) files when the WMV files contain multiple video streams that are intended to be played at the same time. Windows Media Player only plays one of the video streams.

In Windows Vista, Windows Media Player uses Media Foundation to play video that is stored on the local computer. Media Foundation does not support multiple video streams that are intended to be played at the same time.

Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, obtain the hotfix from the Microsoft Download Center.

Download information

The following files are available for download from the Microsoft Download Center:

Windows Vista, 32-bit versions (all languages)

Download the Windows6.0-KB947403-x86.msu package now. (http://download.microsoft.com/download/C/7/D/C7D73C7A-D47B-43F0-8414-12835E149A27/Windows6.0-KB947403-x86.msu)

Windows Vista, 64-bit versions (all languages)

Download the Windows6.0-KB947403-x64.msu package now. (http://download.microsoft.com/download/C/7/D/C7D73C7A-D47B-43F0-8414-12835E149A27/Windows6.0-KB947403-x64.msu)

For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base: 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 prevent any unauthorized changes to the file.

File information

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.

Windows Vista

Windows Vista Service Pack 1

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

After you apply this hotfix, Windows Media Player detects the number of streams in the video file. If the video file contains more than one stream, Windows Media Player uses the Windows Media Format SDK instead of Media Foundation to play the video file.

Multi-bitrate (MBR) videos are videos that contain multiple video streams in the Advanced Streaming Format (ASF) file container. In the ASF header, the multiple streams are differentiated by using a mutual exclusion list. Therefore, only one video stream is played at a time. This configuration enables Windows Media Player to choose the best video stream to play based on the bitrate of the connection between a client and a server.

If no mutual exclusion is set, more than one video can play at the same time in separate windows. Typically, one video plays in Windows Media Player and a second video plays in an Active Movie window that Windows Media Player displays to play the second video.