chaos-stratus 1.1.0

Python tools used to interact with Chaos Stratus effect libraries

chaos-stratus

This package provides tools for interacting with (appropriately compiled) Chaos Audio Stratus pedal effects libraries.

By "appropriately compiled" we mean built with the Stratus build tools available with the most recent versions of Faust, or with the Faust IDE.

Effects that are not built with the Faust tools (e.g. those built before those tools became available) are still at least partially compatible with the library - they may not provide the documented class attributes, but they will provide the operational functions that allow you to interact with them.

In all cases, though, the effect must be built for the platform upon which this class is used - that means performing a "local" build with the Faust tools (or by some other means) or installing this package on the Stratus pedal itself.

Installation

You can install this package using a standard pip invocation

python -m pip install chaos-stratus

Usage/Examples

The main class of these tools is Effect.

You include that into your python script in the standard manner:

from chaos_stratus import Effect

You instantiate the class for a specific effect library as follows:

effect = Effect("path/to/my/effect.so")

See the module documentation for the API available to you.

Examples

Reporting on information concerning the library

import sys
from chaos_stratus import Effect

lib = sys.argv[1]
effect = Effect(lib)
print(f'Stratus effect library {lib}:')
print(f'  Effect name:....... {effect.name}')
print(f'  Effect ID:......... {effect.effectId}')
print(f'  Effect version:.... {effect.version}')
print(f'  Number of knobs:... {effect.knobCount}')
print(f'  Number of switches: {effect.switchCount}')

This is, in fact, what is implemented by the command:

python -m chaos_stratus "path/to/my/effect.so"

Applying the effect on raw sample data

Possibly the most interesting thing you can do with the tools is to apply the effect to test sample data, with different knob and switch values, and check that the output is what you expected.

This is how you can do that with raw sample from stdin, sending output to stdout:

import sys
from chaos_stratus import Effect

lib = sys.argv[1]
effect = Effect(lib)

#
# Set knobs/switches to desired values
#
effect.setKnob(1, 0.5)

#
# Run the effect on stdin
#
BUFFERSIZE=8192
DATA_IN=sys.stdin.buffer
DATA_OUT=sys.stdout.buffer
input_buffer=bytearray(BUFFERSIZE)
while True:
    insize = DATA_IN.readinto(input_buffer)
    if insize == 0:
        break
    DATA_OUT.write(effect.computeBuf(input_buffer[:insize]))

To use that with, say, a wav input file and pump the output to the default output device of your computer (say, your headphones)

• install sox
• write a Python script based on the above sample code
• Find a suitable wav file (or any other format that Sox supports out of the box)
• Run it all like this from the (shell) command line:

sox your-sounds.wav -b32 -e floating-point -r 44100 -t raw - | \
    python my-effect-script.py path/to/my/effect.so | \
    sox -b32 -e floating-point -r 44100 -t raw - -d

Add more effects to your pipeline at will :).