ferraus midi quantize

Snap notes to a grid

Synopsis

ferraus midi quantize <input> [options] [-o <output>]

Maps notes to ticks against the file's tempo map and moves each note-on by strength × (nearest grid point − onset). The grid is ppq × 4 / subdivision ticks (1/8T triplets and 1/8D dotted supported); --swing delays every second grid point by swing × grid; --groove replaces the fixed grid with per-position offsets and velocity deltas from 'midi groove extract'. --humanize adds seeded Gaussian jitter afterwards (--seed).

Examples

Snap every note-on to the nearest sixteenth

ferraus midi quantize take.mid --grid 1/16 -o tight.mid

Pull notes 80% of the way to a swung sixteenth grid

ferraus midi quantize take.mid --grid 1/16 --strength 80% --swing 60% -o swung.mid

Give a stiff part the feel captured from a drummer

ferraus midi quantize part.mid --groove groove.json -o grooved.mid

Options

Flag	Type	Default	Meaning
`--grid`	grid	`1/16`	Grid step: 1/16, 1/8T (triplet), 1/8D (dotted), or auto to detect the dominant subdivision
`--strength`	percent	`100%`	How far notes move toward the grid: 100% lands exactly on it, 50% halves the error Range: 0..100%.
`--swing`	percent	`0%`	Delay of every second grid point as a percentage of one grid step (60% = 0.6 × 1/16) Range: 0..100%.
`--what`	start \| end \| both \| duration	`start`	start: snap note-ons, note-offs follow (durations kept); end: snap note-offs only; both: snap each independently; duration: snap note-ons and round lengths to whole grid steps
`--humanize`	time	`0ms`	Standard deviation of Gaussian timing jitter added after quantizing (15ms); reproducible with --seed
`--min-length`	grid	`1/64`	Notes shorter than this note value after quantizing are lengthened to it
`--no-overlap`	on\|off	`on`	Shorten notes that overlap the next note of the same pitch and channel; drop exact duplicates
`--groove`	path	—	Groove file from 'midi groove extract'; replaces --grid and --swing
`--tracks`	list	—	1-based track numbers to change, comma separated (default: every track)

Global options

Every command also accepts the global options (-o, --json, --dry-run, --overwrite, --progress, ...). See Global options.

Exit codes

Code	Meaning
0	Success
1	Processing failed
2	Usage or parameter error
3	Input missing or unreadable
8	Cancelled
70	Internal error (bug)

Common mistakes

Forgetting that outputs are never overwritten: pass --overwrite or a new -o path when re-running.
Beat-based times (4b, 1/4) need a tempo: pass --bpm or write 4b@120.
Percentages accept 80% or the fraction 0.8; a bare 80 means 80x, not 80%.

For models

MCP tool: ferraus_midi_quantize
Schema: ferraus schema midi quantize
Pipeline: { op: midi quantize, args: { ... } } (flag names with _ instead of -)
fx stage: no

{"command": "midi quantize", "defaults": {"grid": "1/16", "strength": "100%", "swing": "0%", "what": "start", "humanize": "0ms", "min_length": "1/64", "no_overlap": "on"}}