Title: Some users notice degraded audio quality in some Microsoft Teams calls in which any user is connecting using a Cloud PC
User impact: Users may have noticed degraded audio quality in some Microsoft Teams calls when any user connected from a Cloud PC.
More info: This issue specifically impacted one-on-one calls that were expanded to group calls in which any member of the call met all the following conditions:
– At least one user was connecting to the call using a Cloud PC.
– At least one user was connecting using an integrated speaker as the output device and an external microphone as the input device.
Users could successfully bypass the issue using the following methods:
– Affected users could mute and then unmute themselves to clear the issue.
– Users could use the same audio device for both audio input and output to avoid the issue.
Final status: We’ve confirmed that our fix deployment has addressed the offending code regression, and that impact has been remediated.
Scope of impact: A subset of users in Microsoft Teams calls in which another user was connecting using a Cloud PC were impacted.
Start time: Wednesday, September 27, 2023, at 6:43 PM UTC
End time: Tuesday, March 5, 2024, at 10:37 PM UTC
Root cause: A change to update the WebRTC versions, which is an open-source programming interface, was resulting in a code regression to the echo cancellation path, which filters our background noise and echoes during calls, when using a Cloud PC.
Next steps:
– We’re further analyzing the offending change to WebRTC versions along with the introduced code regression to help us identify similar issues during our testing and validation processes and before impact can be produced.
This is the final update for this event.
