Real-time audio buffering for telephone applications

A system that uses an ear proximity sensor to actively manage periods of distraction during telephone conversations is described. We detect when the phone is removed from the ear, record any incoming audio, and play it back when the phone is returned to the ear. By dropping silent intervals and speeding up playback with a pitch-preserving algorithm, we quickly return to real-time without the loss of information. This real-time audio buffering technique also allows us to create a user-activated, lossless instant replay function.