looper is a tool that allows you to easily experiment with a simple form of livecoding for audio generaton. It plays back snippets of audio in a gapless, infinite loop. These snippets are meant to be generated by a program that can be modified. looper then picks up the changes to the program, re-runs it, and switches to the newly generated audio snippet in the next loop.

how it works

Create an executable in a programming language of your choice that outputs floating point numbers to stdout. These will be interpreted by looper as a sequence of audio samples in mono, in 44100 Hertz between -1.0 to +1.0. Here's an example python program noise.py that generates one second of noise:

#!/usr/bin/env python

import random

for i in range(0, 44100):
    print((random.random() * 2.0) - 1.0)

The file has to have the executable flag set (with e.g. chmod +x noise.py). Then run looper, passing in the executable file as an argument:

looper noise.py

This will run noise.py, collect the samples from its stdout and play them back through your audio device in an infinite loop. Once you change and save the program, looper will rerun it and switch to playing the new loop.

You can use this for a simple, experimental form of livecoding by modifying the program over and over again and listening to the results.

Installation

looper runs on linux and mac.

Linux

There's pre-built binaries for linux here.

You will need to install some runtime dependencies to run looper. On ubuntu you can do:

sudo apt install libportaudio2 libsndfile1 libgmp10

Building from source

These are instructions that work on ubuntu-19.10.

First, you need to install some looper dependencies and curl:

sudo apt-get update
sudo apt-get install --yes curl libsndfile1-dev portaudio19-dev

looper is written in Haskell and you need to install the Haskell build tool stack to build and install it. Here's how you can get stack:

curl -sSL https://get.haskellstack.org/ | sh

Then you need to clone the looper repo:

git clone https://github.com/soenkehahn/looper
cd looper

And install looper with:

stack install

stack installs executables into $HOME/.local/bin. So you need to make sure that that's added to your $PATH. If you're using bash you could do that with:

echo 'export PATH="$HOME/.local/bin:$PATH"' >> $HOME/.bashrc

You need to restart bash for this to take effect.

Now you can check that looper is installed with e.g.:

looper --help

Examples

• There are a few small examples in the ./examples folder.
• I (Sönke) have toyed around with looper here: loops.

If you have created anything with looper that is available publicly, we should add it to this list. :)