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 using librosa-based beat detection with energy mapping, drop detection, and onset-aware cut snapping (accurate to within 200ms). 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.