AEC3 is the third-generation acoustic echo canceller in libWebRTC and the default echo remover in Chrome-based calls. It models the echo path from loudspeaker to microphone with an adaptive filter and subtracts the estimated echo from the mic signal, then applies a nonlinear residual-echo suppressor to clean up what the linear filter can't model — important on cheap laptop and phone hardware where speakers distort. AEC3 was engineered for robustness across the huge variety of real-world devices rather than peak performance on ideal ones, handling delay changes, clock drift, and double-talk gracefully. When a WebRTC call has no echo despite a speaker and mic in the same room, AEC3 is usually why.
