ferraus hum

Turn a hummed idea into an instrument part

Synopsis

ferraus hum <input> [options] [-o <output>]

Runs 'transcribe' in mono mode on a voice recording, quantizes the notes ('midi quantize --grid 1/16 --strength 80%'), and renders them with the named sound ('render --instrument'). The intermediate MIDI file is written beside the audio output (idea.wav → idea.mid) so the part can be edited and re-rendered with 'ferraus render idea.mid --instrument strings'. Sounds are found the same way as for render: installed sounds and --sound-path directories first, then General MIDI names played by gm-basic or the built-in synth.

Examples

Hum to piano; also writes idea.mid

ferraus hum voice.wav --to piano -o idea.wav

Strings, tightly quantized to eighths

ferraus hum voice.wav --to strings --grid 1/8 --strength 100% -o strings.wav

A bass line at a fixed tempo (moved into the bass range automatically)

ferraus hum bass-idea.wav --to "Acoustic Bass" --bpm 92 -o bass.wav

Options

Flag	Type	Default	Meaning
`--to`	text	`piano`	Instrument to render with: piano, strings, "Acoustic Bass", gm:48, sf2:<path>, an installed sound name (as render --instrument)
`--grid`	grid	`1/16`	Quantize grid (1/16, 1/8, 1/8T), auto to detect, or off
`--strength`	percent	`80%`	How far notes move toward the grid (80% keeps some feel) Range: 0..100%.
`--bpm`	text	`auto`	Tempo in BPM, or auto to detect it from the humming (also set by the global --bpm)
`--key-snap`	on\|off	`on`	Snap out-of-key notes to the detected key when its confidence is above 0.6
`--octave`	text	`auto`	auto moves the part into the instrument's comfortable range; or a fixed shift in octaves (-1, +1)
`--min-note`	time	`60ms`	Shortest note kept (60ms)
`--onset-sensitivity`	percent	`50%`	How readily repeated or sliding notes are split (see transcribe) Range: 0..100%.
`--tail`	time	`2s`	Time rendered after the last note so it rings out (2s)

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
4	Unsupported format or codec
5	Model not cached and downloads disabled
6	Model download or verification failed
7	Plugin crashed, timed out, or was not found
8	Cancelled
10	Network error
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_hum
Schema: ferraus schema hum
Pipeline: { op: hum, args: { ... } } (flag names with _ instead of -)
fx stage: no

{"command": "hum", "defaults": {"to": "piano", "grid": "1/16", "strength": "80%", "bpm": "auto", "key_snap": "on", "octave": "auto", "min_note": "60ms", "onset_sensitivity": "50%", "tail": "2s"}}