Jitterbufferi

Jitterbufferi is a component used in real-time communications to counter packet arrival time variations, or jitter, by buffering a short sequence of incoming packets and releasing them at a regular playout rate. It is commonly employed in voice over IP, video conferencing, and real-time streaming to smooth playback and reduce audible glitches caused by network variability.

The jitter buffer typically resides at the media endpoint, gateway, or server. It buffers RTP or other media packets, aligns them with the expected playout schedule, and handles late or out-of-order arrivals by delaying playback or discarding late packets. The buffer’s behavior depends on a policy that balances delay against the amount of jitter it can absorb.

Jitter buffers come in fixed-size and adaptive forms. A fixed-size buffer uses a constant delay, providing predictable latency but limited ability to cope with varying network conditions. An adaptive jitter buffer monitors inter-arrival times and adjusts its size dynamically to minimize interruptions while keeping latency within acceptable bounds. Common performance metrics include jitter estimation, buffer occupancy, and the resulting end-to-end delay.

The main trade-off is latency versus audio or video quality: larger buffers reduce drops and glitches but increase total delay, which is detrimental to interactivity. Too small a buffer leads to underruns and gaps; too large a buffer introduces noticeable latency. Jitter buffering is often used together with QoS mechanisms and operates alongside standard streaming protocols such as RTP.