You're muted... or are you? Videoconferencing apps may listen even when mic is off:
Kassem Fawaz's brother was on a videoconference with the microphone muted when he noticed that the microphone light was still on—indicating, inexplicably, that his microphone was being accessed.
[...] "It turns out, in the vast majority of cases, when you mute yourself, these apps do not give up access to the microphone," says Fawaz. "And that's a problem. When you're muted, people don't expect these apps to collect data."
[...] They found that all of the apps they tested occasionally gather raw audio data while mute is activated, with one popular app gathering information and delivering data to its server at the same rate regardless of whether the microphone is muted or not.
The researchers then decided to see if they could use data collected on mute from that app to infer the types of activities taking place in the background. Using machine learning algorithms, they trained an activity classifier using audio from YouTube videos representing six common background activities, including cooking and eating, playing music, typing and cleaning. Applying the classifier to the type of telemetry packets the app was sending, the team could identify the background activity with an average of 82% accuracy.
[...] "With a camera, you can turn it off or even put your hand over it, and no matter what you do, no one can see you," says Fawaz. "I don't think that exists for microphones."
(Score: 2) by hendrikboom on Saturday April 16 2022, @09:37PM (1 child)
Don't need to cancel loudspeaker signal through microphone when the mike is muted.
(Score: 3, Informative) by c on Saturday April 16 2022, @11:50PM
Actually, you still want to adapt the channel model. When you suddenly turn off mute to talk while someone else is talking, the system needs to know the present acoustic channel to cancel that loudspeaker signal. If you don't, everyone gets an annoying echo depending on the adaptation speed of the AEC. It's hard to adapt when you and someone else is talking (known as double-talk in the AEC literature), but easy to adapt when you're not talking.