ferraus fade

Fade in and/or out

Synopsis

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

Fades are computed in gain, not dB, so 'linear' is a straight amplitude ramp. 'log' changes the level evenly in dB (60 dB range), which matches the ear's loudness curve and is the recommended choice for musical fades; 'exp' is its mirror (fast start), 'scurve' eases in and out, and 'equal-power' (sine) suits crossfades. With --in 0s and --out 0s the input is returned unchanged.

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

Examples

Musical fade in and out

ferraus fade song.wav --in 2s --out 4s --curve log -o faded.wav

Fade to silence one second before the end

ferraus fade take.wav --out 500ms --out-end -1s -o cut.wav

One-beat fade-in at 120 BPM

ferraus fade loop.wav --in 1b --bpm 120 -o loop_in.wav

Options

Flag	Type	Default	Meaning
`--in`	time	`0s`	Fade-in length (seconds, ms, beats, or mm:ss)
`--out`	time	`0s`	Fade-out length
`--curve`	linear \| log \| exp \| scurve \| equal-power	`linear`	Fade shape (gain curve)
`--in-start`	time	`start`	Where the fade-in begins; audio before it is silenced
`--out-end`	time	`end`	Where the fade-out reaches silence (e.g. -2s = two seconds before the end); audio after it is silenced
`--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.
Beat-based times (4b, 1/4) need a tempo: pass --bpm or write 4b@120.

For models

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

{"command": "fade", "defaults": {"in": "0s", "out": "0s", "curve": "linear", "in_start": "start", "out_end": "end", "mix": "100%"}}