A workaround for folks experiencing quality issues when using MOC and Vista

*Update – Microsoft published a KB detailing this issue and it is now fixed in the newest version of MOC.  Here’s the KB: http://support.microsoft.com/kb/976054/ the patch is here: http://support.microsoft.com/kb/972884/*

After working with Microsoft for the passed few weeks on a significant audio quality issue we have found what’s causing the problem and a good workaround until a fix is released.

Before I dive into the technical data I want to thank Josh J and all the other folks at Microsoft Dev who have been working non-stop on this issue! 

On to the details:

Problem:  Audio quality is poor when using Microsoft Office Communicator on Vista (any SP or patch level).  Users may expiereince drops in sound or even hear clicking sounds when switching from application to application

Cause:  A behavior in Vista known as “startup boxing” designed to suppress high priority threads during the first 60 seconds of the system boot is not restoring the high priority threads to the appropriate level.  This causes high priority threads such as audio from Communicator (that was started automatically during startup) to be prioritized lower than expected, allowing other applications to take higher priority when not appropriate.

Workarounds:In one of the below work-arounds there is information about editing your registry, please test this functionality in a non-production environment before utilizing, use registry editor at your own risk!

  1. Disable Startup Boxing by changing the following registry key:
    DWORD Delay_Sec
    Default is 60.
    Set to 0 to disable
  2. Turn off the automatic launch of Communicator at boot then start Communicator 60+ seconds after sign on
  3. Close and restart Communicator any time after the 60 seconds so thread priority elevation is not suppressed

This does not apply to anyone running OCPE or other IP based phones, this is only for your MOC clients on Windows Vista. 

I’m told this issue will be addressed in the next QFE (sometime soon), in the mean time feel free to use any of the 3 workarounds above.

About Kevin Peters

My name is Kevin Peters.
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4 Responses to A workaround for folks experiencing quality issues when using MOC and Vista

  1. Nice job Kevin. Do they have an expected release date for the QFE?

    • Kevin Peters says:

      Hey Robin,

      Nice to meet you today! I can’t speak in any certain terms on the release date of the next QFE, I’ve heard rumors of mid-October, but those can’t be confirmed at this point. The KB for this issues still hasn’t been released either as the fix is still with the Dev team.

      Thanks for reading!


  2. Pat Jensen says:

    Kevin – I was experiencing the audio stuttering when switching tasks on Vista. The Nov. patch (3.5.6907.56) seems to clean it up. Thanks for posting on your blog.

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