StepPy: a step sequencer in Python

Using this project, one can:

• Make a MIDI device play a sequence of notes using Python
• Modify and turn notes on / off to create a sequence
• Switch between "step by step" and "live" modes
• Change tempo in real time

Abstractions allow programmers to customize the behaviour for a particular controller.

Bindings are already available for:

• Keith Mc Millen's Quneo ®
• Novation Launch Control ®
• Novation MiniNova ®
• The virtual midi bus available on Mac OS X, to connect to software sequencers

Genesis

This project was demonstrated @ Pycon-Fr 2016.

The slides are available here (soon on this repository).

First demo:

Installation and usage

To install the package and run StepPy:

• Install python, virtualenv and make sure you have a C compiler, portmidi and python headers: e.g. sudo apt-get install -y git python3 python3-virtualenv libpython3-dev libportmidi-dev build-essential on Debian/Ubuntu
• Clone this repository and cd into it
• Create a virtualenv: virtualenv --python=python3 .venv; source .venv/bin/activate
• Run pip install -e . or python setup.py develop
• Connect a supported controller on an USB port
• Run python -m steppy.main or python -m steppy.main load examples/mozart.json

To run tests:

• Run pip install -e .[test]
• Run py.test

Integrated web server (experimental)

StepPy ships with an integrated gevent-based web server with real time updates via Websockets.

To use this server (only works with python 2 for now):

• Install redis and python2 along with other dependencies: e.g. sudo apt-get install -y git python virtualenv libpython-dev libportmidi-dev build-essential redis-server
• Clone this repository: git clone https://github.com/ygravrand/steppy; cd steppy
• Create a virtualenv: virtualenv .venv2; source .venv2/bin/activate
• Run pip install -e .
• Connect a supported controller on an USB port
• Launch redis if not already launched: redis-server --bind 127.0.0.1 --daemonize yes
• Run python -m steppy.main -s or python -m steppy.main -s load examples/mozart.json

Troubleshooting

• Run python -m steppy.main list, this will list the detected inputs and outputs

• Edit conf/steppy.conf and add the corresponding names to a port_name parameter.

  For example:

  [[launchcontrol1]]
  type = launchcontrol
  port_name = Launch Control MIDI 1
  

• On Mac OS X, problems have been reported with system upgrades, resulting in errors like this one. A solution could be to modify <venv>/lib/python2.7/site-packages/mido/backends/portmidi_init.py to specify the absolute location of the library:

  if sys.platform == 'darwin':
      dll_name = ctypes.util.find_library('/usr/local/lib/libportmidi.dylib')
  

  See this discussion for details.

Roadmap

• Chords handling (especially important for a drum machine...)
• Multi track
• Load / save to midi
• External tempo sync
• Reactive Web interface (iPad, ...)