Jitter buffer

Definition

A small queue at the receiver that holds audio packets long enough to absorb the irregular timing of arriving network packets, so playback runs on a smooth clock.

A jitter buffer is a short queue at the receiver that holds arriving audio packets just long enough to smooth out their irregular network timing, so playback can run on a steady clock. Packets sent every 20 ms don't arrive every 20 ms — they bunch up and spread out — and without a buffer that variance becomes gaps and glitches. The buffer trades latency for smoothness: deeper means more packets survive late arrival but more delay is added, shallower means lower delay but more dropouts. Modern buffers are adaptive, growing and shrinking with measured network conditions, and in WebRTC the jitter buffer and concealment are fused into NetEQ.