How rearranger.ai works

Drop a file from your source keyboard. Select source and target models.

The engine normalises channels, remaps drum notes, and detects harmonic sections.

Check the detected root keys and drum mappings. Override anything that needs a human touch.

Your converted style file is ready. Save a drum map for faster future conversions.

The uploaded file is parsed according to the source keyboard's proprietary MIDI-based format spec. For Yamaha, this covers CASM chunks, SFF1/SFF2 style structures, and OTS data. For Korg, the Pa-format arrangement file is decoded. For Ketron, the AKS container is unwrapped. Validation checks that all required sections (Main A/B, Fill, Intro, Ending) are present and structurally intact before any conversion begins.

All MIDI tracks are analysed to identify which channels carry percussion data. Non-drum tracks are preserved as-is for root key analysis. Detected drum tracks are queued for remapping.

Each non-drum channel in each style section is analysed independently to determine the root key of the chord voicings. The analyser uses a chromagram-based approach over the MIDI note distribution, combined with the style's known chord root hints where available.

With drum tracks identified and root keys detected, the engine applies mappings. For drums: each source MIDI note is looked up in the active drum map and remapped to the target note. For chord channels: NTT tables are recalculated based on the detected root key and the target keyboard's chord engine conventions. Korg Guitar Mode and Yamaha Mega Voices are translated into standard MIDI rhythmic patterns so the style plays correctly on any target keyboard.

The remapped MIDI events, section metadata, and NTT data are serialised into the target keyboard's file format. All style sections are written in the correct order with the target's required headers and footers. The output file is validated before it is made available for download.