Audio Input

The in() builtin exposes external audio as a signal source (microphone, tab/system audio, or an uploaded file) so any Cedar effect can process it. The host p…

The in() builtin exposes external audio as a signal source (microphone, tab/system audio, or an uploaded file) so any Cedar effect can process it. The host populates the input buffer each block.

in

Live audio input - Returns a stereo signal from the host’s selected input source.

Param	Type	Default	Description
source	string	(UI default)	Optional override: `"mic"`, `"tab"`, or `"file:NAME"`

Output: Stereo signal. Mono effects automatically run per-channel via auto-lift, so in() |> lp(%, 2000) is a stereo lowpass with independent state per side.

Examples

Filter the microphone:

in() |> lp(%, 2000, 0.7) |> out(%)

Granular delay on the live source:

in() |> delay(%, 0.25, 0.5, 0.5, 0.5) |> out(%)

Mix live input with a synth voice:

sig = in()
osc = osc("saw", 220) * 0.3
sig + stereo(osc) |> out(%)

Override the source per-program (a string literal, resolved at compile time):

in("mic")              // microphone
in("tab")              // tab / system audio (browser only)
in("file:voice.wav")   // an uploaded file, looped

The argument is a compile-time string. The compiler does not interpret it semantically; it forwards it to the host as metadata. The host (web UI dropdown, CLI --input-device, Godot binding) decides what to do with it.

Multiple in() calls

All in() calls in a single program share the same input buffer. There is one stereo input source per execution context. Calling in() twice does not allocate a second source; it reads the same data.

Silent fallback

When no input is available (permission denied, device unplugged, file not yet uploaded, host without input support), in() silently returns zeros. There is no compile error and no crash. The UI shows the current input status so you can see whether in() is actually live.

Where the audio comes from

Host	Source selection
Web	Settings panel → Audio Input. Pick Mic (browser permission prompt), Tab (`getDisplayMedia`, requires “Share tab audio”), or File (drag/drop a WAV).
CLI (`nkido-cli`)	`--list-devices` enumerates capture devices; `--input-device "Name"` selects one. Defaults to the system default.
Godot	Extension wires `ctx.input_left/right` from the chosen Godot bus or `AudioStreamMicrophone`.

Feedback warning

Mic-in → speakers-out without headphones causes feedback. Use headphones, or attenuate the wet signal until you understand the loop. Feedback-loop detection is not built-in; the loud screech is on you.