Chipnumpy

Chipnumpy is a module for creating simple chiptune style audio waveforms using numpy.

Chipnumpy was inspired by chippy. It has a similar API and generates the same types of waveforms. Unlike chippy, chipnumpy uses numpy, which makes it significantly faster.

To install:

pip3 install chipnumpy

For example implementation, see examples/c_scale.py (requires pygame to play the audio).

Synthesizer API

The constructor

Start to generate audio by creating a Synthesizer:

from chipnumpy.synthesizer import Synthesizer

s = Synthesizer()

You can optionally set the random seed: s = Synthesizer(seed=0). This is used when generating noise waveforms; it can be useful if you want to recreate noise waveforms with the same seed.

Generate a sine waveform

from chipnumpy.synthesizer import Synthesizer

s = Synthesizer()
data = s.sine(note=293.66, amplitude=0.5, length=1.1)

note is either a frequency in Hz, or a string representing a note + octave:

from chipnumpy.synthesizer import Synthesizer

s = Synthesizer()
data = s.sine(note="C5", amplitude=0.5, length=1.1)

amplitude controls the volume and is clamped to be between 0 and 1.

length is the duration of the waveform in seconds.

The returned data is an int16 byte array.

Generate other waveforms

To generate a triangle waveform: data = s.triangle("C5", 0.5, 1.1)

To generate a sawtooth waveform: data = s.sawtooth("C5", 0.5, 1.1)

To generate a pulse waveform: data = s.pulse("C5", 0.5, 1.1) You can optionally set the duty cycle parameter, which controls the length of the pulse (must be between 1 and 100): s.pulse("C5", 0.5, 1.1, duty_cycle=50).

To generate a sawtooth waveform: data = s.sawtooth("C5", 0.5, 1.1)

To generate a noise waveform with the same syntax: data = s.noise("C5", 0.5, 1.1) This uses random values; see above for how to seed the random number generator.

Generate and write wav data

To convert data to wav data (i.e. to add a wav header): wav = s.to_wav(data)

To convert data to wav data and write to disk: s.write(data, path) where data is an int16 byte array and path is either a string or a Path.