Resync

Resync, short for resynchronization, is the process of restoring alignment between two or more systems, streams, or components that have become out of sync. Desynchronization can arise from clock drift, varying processing delays, packet loss, or data corruption, and resynchronization re-establishes a common reference or timing.

In timekeeping and distributed systems, resync refers to re-aligning clocks across devices so that timestamps or events share a coherent timeline. This is often achieved through time synchronization protocols such as Network Time Protocol (NTP), Precision Time Protocol (PTP), or internal loop corrections, sometimes triggered automatically after drift is detected.

In digital communications and media delivery, resynchronization corrects drift between transmitted and received signals. Clock recovery and phase adjustment techniques align the receiver's clock with the incoming data, while framing or symbol synchronization ensures the receiver can correctly reassemble data packets or video frames after interruptions or jitter. In multimedia workflows, resync may refer to re-aligning audio and video tracks after edits, encoding, or streaming hiccups, to restore lip-sync.

In distributed storage and databases, resync describes rejoining a cluster after a partition or failure and converging replicas to a consistent state through anti-entropy or reconciliation protocols.

Common methods include buffering to absorb jitter, timestamp or sequence-number alignment, phase-locked loops, and explicit resync markers or handshake messages. The goal is to minimize latency and prevent data corruption or perceptible desynchronization.

See also synchronization, clock drift, jitter buffer, and clock recovery.