Microsoft KB Archive/888263

= Media files that are created in Windows Media Encoder 9 Series by using source group switching may not be synchronized when they are played back =

Article ID: 888263

Article Last Modified on 3/14/2007

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APPLIES TO


 * Windows Media Encoder 9 Series

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SYMPTOMS
The audio and video may not be synchronized in a media file that you create in Microsoft Windows Media Encoder 9 Series when the following conditions are true:
 * You add multiple source groups to a session in Windows Media Encoder 9 Series.
 * You then repeatedly switch between the source groups.

Note This problem occurs when you play back the file in Microsoft Windows Media Player 7 and later versions.



CAUSE
This problem occurs because of the way that the objects in the Microsoft Windows Media Format Software Development Kit (SDK) handle the remaining audio samples from the previous source when you switch between source groups. The samples are handled in this way to prevent audio errors in the media file. This behavior may cause problems with synchronization when you use source group switching to encode the media file.



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



Steps to reproduce the behavior

 * 1) Start Windows Media Encoder 9 and create a custom session.
 * 2) On the toolbar, click Properties.
 * 3) Click the Sources tab, click Add, and then configure the following two sources:
 * 4) * Set Source 1 to encode a video and audio source.
 * 5) * Set Source 2 to encode the audio source that Source 1 is encoding and to encode a different video source.
 * 6) Click the Output tab, and then click Archive to file.
 * 7) In the File name box, type the name of your file, and then click Apply.
 * 8) Click Start Encoding.
 * 9) In the Source pane, click Source 1, and then click Source 2.
 * 10) Repeat step 7 several times.

Note Wait for several seconds before you switch between sources.
 * 1) Click Stop.
 * 2) In Windows Media Player, view the media file that you created in step 5.

