ferraus channels

Mix down, up-mix, extract, swap, or mid/side-convert channels

Synopsis

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

Does one channel operation per run. --to mono averages the channels; --to stereo copies a mono signal to both sides (and folds 5.1 down with the ITU coefficients). --extract keeps one channel as a mono file. --swap exchanges left and right. --mid-side encode turns L/R into mid (L+R)/2 and side (L-R)/2; decode reverses it exactly.

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

Examples

Average left and right into one channel

ferraus channels stereo.wav --to mono -o mono.wav

Keep only the right channel (the guest's mic)

ferraus channels interview.wav --extract R -o guest.wav

Get mid in channel 1 and side in channel 2 for M/S processing

ferraus channels mix.wav --mid-side encode -o ms.wav

Options

Flag	Type	Default	Meaning
`--to`	mono \| stereo	—	Convert to mono or stereo
`--extract`	text	—	Keep one channel: L, R, C, or a channel number from 1
`--swap`	flag	—	Swap the left and right channels
`--mid-side`	encode \| decode	—	encode: L/R to mid/side; decode: mid/side back to L/R

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_channels
Schema: ferraus schema channels
Pipeline: { op: channels, args: { ... } } (flag names with _ instead of -)
fx stage: yes

{"command": "channels", "defaults": {}}