Microsoft KB Archive/942195

= FIX: You may hear noise when you use DirectShow to play an MP3 file on a Windows CE 5.0-based device =

Article ID: 942195

Article Last Modified on 10/11/2007

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APPLIES TO


 * Microsoft Windows CE 5.0

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SYMPTOMS
Consider the following scenario. On a Microsoft Windows CE 5.0-based device, you use Microsoft DirectShow to play an MP3 file. During playback, another application starts a thread that has a higher priority than DirectShow. In this scenario, you may hear noise during playback.



CAUSE
This problem occurs when the MP3 decoder file buffer is not large enough.



Update information
A supported software update is now available from Microsoft as Windows CE 5.0 Platform Builder Monthly Update (September 2007). You can confirm this by scrolling to the &quot;File information&quot; section of this article. The package file name contains the product version, date, Knowledge Base article number, and processor type. The package file name format is:

Product version-yymmdd-kbnnnnnn-processor type

For example: Wincepb50-060503-kb917590-armv4i.msi is the ARMV4i Windows CE 5.0 Platform Builder fix that is documented in KB article 917590 and that is contained in the May 2006 monthly update. To resolve this problem immediately, click the following article number for information about obtaining Windows CE Platform Builder and core operating system software updates:

837392 How to locate core operating system fixes for Microsoft Windows CE Platform Builder products

Prerequisites
This update is supported only if all previously issued updates for this product are also installed.

Restart requirement
After you apply this update, you must perform a clean build of the whole platform. To clean the platform, click Clean on the Build menu. To build the platform, click Build Platform on the Build menu. You do not have to restart the computer after you apply this update.

Update replacement information
This update does not replace any other updates.

File information
The English version of this package has the file attributes (or later file attributes) that are listed in the following table.

The English version of this update 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.



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.



MORE INFORMATION
After you apply this update, original equipment manufacturers (OEMs) can configure the minimum allowed size for MP3 DirectX Media Object (DMO) buffer requests. To do this, OEMs must add the following registry entry in their registry configuration files, or OEMs must modify the following registry entry in their registry configuration files:

[HKEY_LOCAL_MACHINE\Software\Microsoft\DirectX\DirectShow\MP3Decoder] &quot;MinBufferSize&quot;=dword:4000

Note The value of the MinBufferSize registry entry is a hexadecimal value that represents the minimum allowed size in bytes. The default hexadecimal value of 4,000 equals 16,384 bytes or 16 KB.

