ferraus pitch

Shift pitch, keep duration

Synopsis

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

Shifts pitch by semitones and cents without changing the length. With --formant preserve (the default) the voice keeps its tone colour: the high-quality path is a phase vocoder with identity phase locking and cepstral formant-envelope correction (its lifter follows the detected pitch); --quality fast uses TD-PSOLA for monophonic voiced material and a lighter vocoder otherwise. --formant shift moves formants with the pitch (the 'chipmunk' effect).

This command is also an fx stage and a pipeline op: ferraus fx in.wav -o out.wav --fx "pitch:key=value".

Examples

Up a major third, formants preserved

ferraus pitch vocal.wav --semitones 4 -o up.wav

Down 185 cents

ferraus pitch guitar.wav --semitones -2 --cents 15 -o down.wav

Shift formants with the pitch

ferraus pitch voice.wav --semitones 7 --formant shift -o chipmunk.wav

Options

Flag	Type	Default	Meaning
`--semitones`	cents\|semitones	`0`	Shift in semitones, e.g. 4, -3, +0.5 (st)
`--cents`	cents\|semitones	`0`	Additional shift in cents (100 cents = 1 semitone)
`--formant`	preserve \| shift	`preserve`	preserve keeps formants in place; shift moves them with the pitch
`--quality`	high \| fast	`high`	high: 8x-overlap phase vocoder; fast: PSOLA (voice) or 4x vocoder
`--mix`	percent	`100%`	Dry/wet balance: 0% returns the input unchanged, 100% is fully processed

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
8	Cancelled
70	Internal error (bug)

Common mistakes

Forgetting that outputs are never overwritten: pass --overwrite or a new -o path when re-running.

For models

MCP tool: ferraus_pitch
Schema: ferraus schema pitch
Pipeline: { op: pitch, args: { ... } } (flag names with _ instead of -)
fx stage: yes

{"command": "pitch", "defaults": {"semitones": "0", "cents": "0", "formant": "preserve", "quality": "high", "mix": "100%"}}