The grid is the authority

Most DJ tools that generate cue points have a trust problem: they analyze the audio with their own engine, decide where the beats are, and write what they found. If their guess is off by half a beat, your cue is wrong and your library absorbs the mistake.

Metamix inverts that. Rekordbox's beatgrid is the single timing authority. The cue engine doesn't decide where the beats are — it reads the grid Rekordbox will actually play with, and snaps every cue to it.

What that means in practice

• Structure informs, the grid decides. Metamix detects phrases, builds, and drops from the audio, but every boundary is quantized to the 8/16-bar hypermeter on top of the Rekordbox grid.
• No grid, no cues. If a track has no valid beatgrid, Metamix tells you to fix it in Rekordbox first. It would rather do nothing than write something wrong.
• Your manual edits win. Tracks where you've set cues by hand are marked yours. Automated writes to them are blocked, full stop.

Writes you can undo

When the engine does write, it takes a Rekordbox snapshot first, shows you the exact diff — every cue, every tag, before and after — and audits the batch. If you don't like what it did, one click rolls it back.

That's the bar: no silent changes to a library you spent years building.