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Cisco Telepresence System - Audio clipping sharing presentation music only for Cisco Telepresence


Problem Description

Audio clipping is heard while sharing a presentation via VGA cable from a directly connected laptop that is playing music only during a Cisco Telepresence call. The video works flawlessly but playing music only triggers audio clipping.

Conditions / Environment

User sharing presentation while using a laptop directly connected via VGA cable for Cisco Telepresence.

Cause / Problem Description

The acoustic echo canceller is optimized for human speech, not music. Noise suppression will mistakenly identify certain frequencies in music for noise and attempt to suppress/cancel it.

Also, doubletalk will certainly add to the clipping behavior.

When playing audio via presentation, if someone talks, the AEC will kick in and suppress the audio, causing clipping unless the microphones are muted.  If the microphones are muted, the AEC then doesn’t have the chance to kick in.  The AEC is working as designed for Cisco Telepresence


Muting the microphones on the side sending/sharing the presentation will suppress the audio locally, which can trigger the audio clipping by the AEC. If the microphones are muted, the AEC then doesn’t have the chance to  kick in.