MIDI Editor
OCTAVE's central piano-roll surface. The editor is canvas-based for fluid scroll/zoom, and supports per-instrument lane layouts.
Tools
| Hotkey | Tool | Behavior |
|---|---|---|
1 | Select | Click to select notes; drag to box-select; drag a selected note's right edge to extend a sustain. |
2 | Place | Click empty space to drop a new note at the snap position. |
3 | Erase | Click a note (or drag through several) to delete. |
You can switch tools at any time. Holding Shift while clicking with the Select tool adds to the current selection; holding Ctrl/Cmd toggles individual notes.
Snap
The toolbar dropdown sets the snap division — 1/4 through 1/64 of a beat. Snap affects:
- Where the Place tool drops new notes
- Where dragged notes land
- The grid overlay density
Modifiers
Modifier toggles appear in the toolbar; clicking applies to all selected notes. Hotkeys for toggles:
| Hotkey | Modifier | Notes |
|---|---|---|
S | Star Power phrase | Adds the selection to a star power phrase |
G | Solo phrase | Marks a solo section |
F | Force HOPO / Strum | Toggles between HOPO and strum on guitar/bass/keys |
O | Open / Kick | 5-fret guitar open notes; drums kick |
P | Tap | 5-fret tap modifier |
L | Sustain release | Removes the sustain |
T | Tom (drums) | Toggles cymbal vs. tom on yellow / blue / green |
See the Keyboard Shortcuts reference for the full list.
Multi-difficulty editing
The difficulty tabs above the lanes let you author Expert / Hard / Medium / Easy independently. The active difficulty is what's edited and displayed in the Chart Preview.
Songs produced by Auto-Chart already arrive with all four difficulties filled in. For charts you wrote by hand, or imported with only an Expert track, use Generate from Expert.
Note: Copy / paste keeps each note on the difficulty it was copied from. Pasting Expert notes while a lower difficulty tab is active adds them back to Expert, not to the tab you're viewing.
Generate from Expert
The Generate from Expert button in the piano-roll toolbar derives Hard / Medium / Easy from your Expert chart, using the same reduction rules Auto-Chart applies. Tick the instruments and the difficulties you want, then hit Generate.
It covers drums, guitar, bass, keys, Pro Keys and Pro Guitar / Bass. Vocals are absent because CH / RB have no per-difficulty vocal charts. An instrument with no Expert notes is skipped rather than blanked.
What the rules do, broadly:
| Instrument | Hard | Medium | Easy |
|---|---|---|---|
| Drums | Drops ghost notes and very fast repeats, thins busy hi-hat | Kick to a basic pulse (no double kick), hi-hat halved, toms only on accents | Kick and snare only, very sparse |
| Guitar / Bass | Thins dense runs, caps frets at blue, no taps | No 3-note chords, thins harder, strum-only | Single notes, capped at yellow, sparsest |
| Keys / Pro Keys | Drops every 4th note | Every other note, voicings cut to two | Every 3rd note, one voice per onset |
| Pro Guitar / Bass | Voicings capped at four strings | Capped at two strings | Single low string per onset — frets are never transposed |
Two things worth knowing before you run it:
- It replaces, it doesn't merge. Any hand-authored work on the difficulties you tick is discarded for the instruments you tick. The popover tells you how many notes that is before you commit, and
Ctrl/Cmd+Zputs them back in one step. - Reduction is gap-based, so slow songs reduce less. The thresholds are in milliseconds, not beats. On a sparse or slow chart, Hard can come out identical to Expert simply because no passage is dense enough to thin. Treat the output as a starting point to tweak, not a finished chart.
Copy / paste & undo
Ctrl/Cmd+C/Ctrl/Cmd+V— copy / paste preserves relative timingCtrl/Cmd+Z/Ctrl/Cmd+Shift+Z— undo / redo (per-song history)Delete— remove selection
Per-instrument lanes
| Instrument | Lanes |
|---|---|
| Drums | Kick, Red, Yellow (cymbal/tom), Blue, Green, 2x kick |
| Guitar / Bass / Keys | Open, Green, Red, Yellow, Blue, Orange |
| Pro Keys | Full 25-key MIDI range |
| Pro Guitar / Bass | 6 strings × frets, plus chord modifier |
| Vocals | Pitched melody + HARM2 / HARM3 harmonies |
Lane swap
The Swap Lanes button in the piano-roll toolbar opens a popover where you pick an instrument and two of its lanes, then swap every note between them. It covers guitar / bass / keys (open, green, red, yellow, blue, orange), drums (kick, snare, and the tom / cymbal variants) and Pro Guitar / Pro Bass strings 1–6; Pro Keys and vocals aren't supported.
The All difficulties checkbox is ticked by default, so the swap applies to every difficulty. Untick it to limit the swap to the difficulty you're currently editing.