README.md

Faust.jl

Julia wrapper for the Faust compiler.

Uses the Faust LLVM C API.

Usage

using Faust

# Create a DSP factory.
dsp = compile("""
import("stdfaust.lib");

freq = hslider("freq", 440, 20, 20000, 1);
gain = hslider("gain", 0.25, 0, 1, 0.001);
process = os.oscs(freq) * gain;
""")

# Initialize DSP instance and controls.
init!(dsp; block_size=1024, samplerate=48000)

# Compute one block of audio.
compute!(dsp)

By default, programs are compiled as single-precision; you can give -double or other arguments to the compiler like so:

compile("process = _;"; name="passthrough", argv=["-double", "-vec"])

Each call to compute! will calculate block_size samples and return the output as a matrix of (block_size, n_channels). If the program takes input, set dsp.inputs to a (block_size, n_channels) matrix before calling compute!:

passthrough = init!(compile("process = _, _;"))
x = rand(Float32, 256, 2)
passthrough.inputs = x
@test compute!(passthrough) == x

After calling init!, any UI elements declared in your code will have their path names and ranges available via dsp.ui.ranges.

julia> dsp.ui.ranges
Dict{String, Faust.UIRange} with 2 entries:
  "/score/gain" => UIRange(0.25, 0.0, 1.0, 0.001)
  "/score/freq" => UIRange(440.0, 20.0, 20000.0, 1.0)

julia> ctrl = dsp.ui.ranges["/score/freq"]; (ctrl.min, ctrl.max)
(20.0f0, 20000.0f0)

One can then set the values of these params like:

setparams!(dsp, Dict("/score/freq" => 220.0f0))

See examples/portaudio.jl to understand how the DSP can be wrapped for audio IO.