LabSoundC

LabSoundC is a minimalist C binding for the LabSound audio engine, designed for real-time game and synth environments. All objects are opaque handles owned by the context -- zero memory management overhead for the host. The pin-centric graph model exposes inputs, outputs, and parameters uniformly, making it ideal for visual node-graph editors. Wraps ~30 WebAudio-derived node types. Bindings for Python and Zig included.

Features

• ~68 C functions covering the full LabSound API
• Opaque handle system (Node, Pin, Conn, Bus) with generational IDs
• Hybrid pin model: unified ls_Pin for enumeration + typed ls_Output/ls_Input/ls_ParamInput for connection safety
• Complete parameter automation (setValueAtTime, linearRamp, exponentialRamp, setTarget)
• Audio-rate parameter modulation (connect oscillator output to filter frequency)
• Normalized name matching (case-insensitive, space-insensitive)
• 30 node types: oscillators, filters, delays, compressors, noise, ADSR, spatial audio, recording, custom DSP
• Python (ctypes) and Zig bindings
• Shared + static library builds

Quick Start

cd LabSoundC
cmake -B build .
cmake --build build
./build/labsoundc_demo      # plays 4 procedural effects

Three Languages, One API

C:

ls_ContextDesc desc = {0};
ls_Context* ctx = ls_context_create(&desc);
ls_Node osc = ls_node_create(ctx, "Oscillator");
ls_Node gain = ls_node_create(ctx, "Gain");
ls_Node dest = ls_destination_node(ctx);
ls_param_set_value(ctx, ls_node_param(ctx, gain, "gain").pin, 0.25f);
ls_connect(ctx, ls_node_output(ctx, osc, 0), ls_node_input(ctx, gain, 0));
ls_connect(ctx, ls_node_output(ctx, gain, 0), ls_node_input(ctx, dest, 0));
ls_node_start(ctx, osc, 0.0);

Python:

with Context() as ctx:
    osc = ctx.create_node("Oscillator")
    gain = ctx.create_node("Gain")
    gain.param("gain").value = 0.25
    connect(osc.output(0), gain.input(0))
    connect(gain.output(0), ctx.destination_node.input(0))
    osc.start()
    time.sleep(1)

Zig:

var ctx = try Context.init(null);
defer ctx.deinit();
const osc = ctx.createNode("Oscillator");
const gain_node = ctx.createNode("Gain");
const dest = ctx.destinationNode();
gain_node.param(ctx, "gain").setValue(ctx, 0.25);
ctx.connect(osc.output(ctx, 0), gain_node.input(ctx, 0));
ctx.connect(gain_node.output(ctx, 0), dest.input(ctx, 0));
osc.start(ctx, 0.0);

Documentation

• BUILDING.md -- build instructions for C, Python, and Zig
• docs/manual.md -- full user's manual, API reference, and audio cookbook

Procedural Audio Demos

The demo app (examples/demo.c) plays four procedural sound effects built entirely through the C API:

• Red Alert Warble -- FM sweep through a resonant filter bank with delay chorus
• Twittering Bird -- rapid FM chirps with randomized timing and envelope shaping
• Marble in a Tin Can -- noise bursts through tuned resonant filters simulating metal resonance
• Passing Train -- rhythmic chug with stereo panning sweep and simulated Doppler shift

Run a single demo with ./build/labsoundc_demo [1-4], or all four sequentially with no argument.

Project Structure

LabSoundC/
  include/LabSoundC/LabSoundC.h    C API header
  src/LabSoundC.cpp                 Implementation
  examples/                         C smoke test + demo
  bindings/python/                  Python ctypes bindings
  bindings/zig/                     Zig idiomatic bindings
  docs/manual.md                    User's manual

License

BSD-2-Clause. Copyright 2022-2026 Nick Porcino and the LabSound Authors.