High Glitch rate in QoE Report


If your organization uses Lync Monitoring Reports, CQM you may occasionally see high glitch rate in one or more calls. Both reports typically show you calls with very high glitch rate.

In-order to resolve the issue, we first need to understand what a glitch really is.

A glitch is defined as a short-lived fault in a system. It is often used to describe a transient fault that corrects itself, and is therefore difficult to troubleshoot.

In a Lync or Skype for Business related setting, a Glitch is a short span of time, when the application was unable to have exclusive control of the device. This can be caused, because either another application wanted to use the device, like a Browser wanting to auto-play a video, or a PowerPoint presentation that has audio in it.

Our recommendations for glitch are as follows

AudioSpeakerGlitchRate
Average glitches per five minutes for the loudspeaker rendering. For good quality, this should be less than one per five minutes. Not reported by A/V Conferencing Servers, Mediation Servers, or IP phones.

AudioMicGlitchRate
Average glitches per five minutes for the microphone capture. For good quality this should be less than one per five minutes. Not reported by A/V Conferencing Servers, Mediation Servers, or IP phones.

See: https://technet.microsoft.com/en-us/library/gg398064.aspx

Every Lync call has audio sampling at either 8,000 Samples/Sec (narrowband) or 16,000 samples/sec (Wideband) and a glitch is failure to capture one or more consecutive samples.

If your organization is using a capture and render device that is  optimized for Lync then you should indeed expect few glitches.

Our certification Process requires the following

Lync User Experience

  • Plug and play: once connected, a device registers on Lync server and is ready to use
  • First run experience: Automatic detection of a device with a direct link to user guide and other useful tools and documentation
  • Mute/unmute across PC and device
  • Audio quality (embedded in the device): no echo or excessive glitches, echo cancellation across devices, wideband / Microsoft media platform with RT audio
  • Anti-flicker support for webcams (global powerline frequency) admin experience

See: https://technet.microsoft.com/en-us/office/dn788944.aspx

If you do experience an issue with Glitches, I would recommend, to begin troubleshooting, by first updating any/every device driver that’s used for Audio and Video on the PC where the glitch rate is high, simply by downloading and installing the latest versions from the appropriate vendor’s web-site.

Next, I would suggest to test again, and if the issue continues to occur, and/or isn’t reduced drastically, to check all USB peripherals, and then to update the devices. If you are using a say, a Universal Docking Station, please download the device drivers from the vendor for the same.

If say, you are using a USB Hub or or are connecting the device using a docking station, it would be prudent to test with a direct connection. Even using a different USB port may help.

To troubleshoot the issue, I would typically perform the following

  1. Request the user to Run MSInfo32.exe and then Click File –> Save ( Save in NFO format)
  2. Run the following in PowerShell to get a list of all available drivers
    dir C:\windows\System32\drivers\*.*  | %{ $_.VersionInfo} | ConvertTo-Html > C:\Windows\Temp\drivers.html
  3. Collect Data using Windows Performance Recorder (WPR)
    1. Download and Install Windows Assessment and Deployment Kit (Windows ADK) from https://developer.microsoft.com/en-us/windows/hardware/windows-assessment-deployment-kit for your operating System
    2. Once you have installed Windows ADK, can you please search for Windows Performance Recorder (WPR) and select Scenario Audio Glitches, and ensure to de-select “First Level Triage”, also change the logging to Verbose and Logging Mode to File
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    3. Start Click on Start, and then attempt a call in Lync / Skype for Business
    4. Once you have about 60 seconds in the call click on SAVE in Windows Performance Recorder (WPR)
    5. At this point, we have the ETL file
    6. We would also want to click SAVE in the next window.

Once you have data from above, it can be used by Microsoft Premier Support to analyze

If you are interested to learn, what’s in the data that was collected, and how we analyze them, you might want to view https://channel9.msdn.com/Shows/Defrag-Tools/Defrag-Tools-151-Media-eXperience-Analyzer-part-3-Audio-Glitch-Analysis

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