What you prep in Rekordbox
is what plays on the deck.

Why Re-encoding is Safe at High Bitrates

A common concern is quality loss when re-encoding MP3/AAC. However, for gain adjustment only at high bitrates (≥256 kbps), the degradation is completely inaudible.

• Quantization noise below -90dB — far below audible threshold
• ABX tests confirm — listeners cannot distinguish 320kbps→320kbps re-encodes
• Waveform preserved — gain is simple multiplication, no compression or EQ applied
• Club environment — any theoretical difference is masked by ambient noise and PA characteristics
• High-quality encoders — headroom uses libmp3lame/libfdk_aac with best quality settings

Why this matters for CDJ users

headroom exists because Rekordbox's Auto Gain doesn't follow your tracks onto the CDJ — the analyzer fixes that by baking gain into the audio files, so the loudness work survives USB export.

rbsort is the same idea applied to playlist order. Rekordbox can't multi-column sort, and even if it could, CDJs play tracks in playlist order, not by software sort. rbsort bakes the Key+BPM order into the playlist itself, so the harmonic-mix prep you do at home shows up on the deck without any reordering at the gig.

Workflow

1. Set key display to Alphanumeric (1A..12B notation) in Rekordbox: Preferences → View → Key display format → Alphanumeric
2. Export your collection: File → Export Collection in xml format
3. Run headroom rbsort against the exported XML (omit --playlist to sort every TrackID-referenced playlist at once, or pass --playlist "Name" to target one)
4. Point Rekordbox at the output: Preferences → Advanced → Database → rekordbox xml → Imported Library → select the output file, then restart Rekordbox (the XML is only read on startup)
5. Open the rekordbox xml tree in the left sidebar — it's a separate tree from your main library, accessed via the sidebar icon column on the far left. The sorted results live in a new folder at rekordbox xml → Playlists → Sorted (Key+BPM)/, each playlist named after its source
6. Verify the sort by clicking any playlist inside Sorted (Key+BPM)/: tracks run 1A (lowest BPM) → 1B → 2A → … → 12B (highest BPM)
7. Drag the playlists you want out of Sorted (Key+BPM)/ into your main Playlists to use them in your sets — your originals are untouched
8. Export to USB for CDJ: switch Rekordbox to EXPORT mode (top-left dropdown), plug in your USB / SD, then right-click the playlist → Export Playlist. The CDJ reads the playlist in the order it's stored — Key+BPM order travels to the deck

Don't see it? The sorted results live only inside the rekordbox xml → Sorted (Key+BPM)/ folder, not in your main Playlists. If you only see the originals, switch sidebar trees.

Sort Rules

• Primary: Camelot Key ascending — 1A → 1B → 2A → 2B → … → 12A → 12B
• Secondary: BPM ascending within each key group
• Tracks with no Camelot key sort after all known keys
• Tracks with BPM 0 / unanalyzed sort last within their key group
• Your original collection.xml is never modified — output goes to a separate file with a new Sorted (Key+BPM)/ folder appended
• Originals stay in place; the sorted copies live inside Sorted (Key+BPM)/ and reuse the source playlist names (same pattern as the analyzer's backup/ directory)

Single-column sort vs. multi-column sort

Rekordbox and the CDJ-3000 / XDJ-1000MK2 can sort a list by Key or BPM — but never both at once. Given the same input playlist, the three sort modes produce different orderings:

See docs/rbsort-sort-comparison.md for a 6-track walk-through showing the actual track ordering each mode produces.