What is beat sync in video editing?

Beat sync (or beat-synced editing) means placing video cuts, transitions, or effects exactly on the rhythmic beats of a song. When done well, it creates a visceral connection between what you see and what you hear.

How it works manually: Import your song into a video editor. Listen and place markers on every beat. Cut your clips to fit between markers. Adjust timing frame by frame. A 4-minute song with 120 BPM means roughly 480 beat markers to place. This takes 2-4 hours.

How Onset Engine automates it: Import your clips and song. The AI analyzes the audio with a neural beat + downbeat model (Beat This!, bundled and offline), plus energy mapping, drop detection, and onset-aware cut snapping (accurate to within 200ms). Downbeats matter more than they sound like they should - knowing where each bar starts is what lets it change pace at a musically sensible moment instead of an arbitrary one. Clips are automatically placed on detected beats. Preview, adjust with Curator tools if needed, export.

The difference between basic and good beat sync: Basic just cuts on every beat (robotic, monotonous). Good beat sync varies with song energy - fast cuts on drops, longer holds on verses, transitions on section changes. Onset Engine does the good version automatically because it understands song structure, not just beat positions.

There's also a free demo available that includes the full AI pipeline, all 9 presets, and all VFX - just with a watermark and 720p/30fps cap. Good way to test the beat detection quality before buying.