Framesynkronointisignaali

Framesynkronointisignaali, known in English as a frame synchronization signal, is a timing signal used in video and broadcast systems to indicate the start of a new frame. In analog video formats such as composite and component video, the sync signal consists of a horizontal sync pulse that marks the end of one line and a vertical sync pulse that marks the end of the last line of a frame. The vertical sync is typically a longer pulse or a series of pulses that signals the display or recording equipment that a new frame is arriving, allowing the electron beam or scanning circuit to return to the top of the image.

Digital video systems use a different representation of frame sync. In standards such as DVI, HDMI, and DisplayPort, a dedicated sync word or control pattern is embedded in the data stream to delineate frames. For example, HDMI uses a 10‑bit start code followed by frame integrity codes, while the Digital Video (DV) format includes a 32‑bit header with a sync marker. In broadcast and streaming contexts, transport streams (TS) include both a program clock reference (PCR) and frame boundaries that aid in synchronization between encoder and decoder.

The primary purpose of a frame sync signal is to provide a reliable reference point so that display devices, recording equipment, and downstream processing stages can align their internal clocks to the incoming data, maintaining proper timing even in the presence of jitter or packet loss. In professional video workflows, accurate framing ensures that overlay graphics, subtitles, and closed caption data are correctly aligned with the visual content.

The term is largely used in the context of video engineering, broadcasting, and multimedia production. It is often referenced in technical documentation and standards that govern video transmission and display technologies.