PyChoReLib for Python 2.3

Why this project?

• This projection was born out of enthusiasm
• Enthusiasm about music and different ways to describe it using one of many music theories.
  
• Enthusiasm about the Python programming language.
  
  
• This project was born out of frustration
  
• Existing open source auto-accompaniment systems typically specify chords using chord names
  despite lists of note names feeling more natural to me.
  
• Not many people have open sourced their code to recognize chords --- or if they have, they hid it well.
  Many projects, on the other hand, have some plans to add chord recognition capabilities to their system in the "future".
  

Purpose

• The library provides in a number of classes which offer the following functionality:
  
• transformation of a list of note names to a chord name:
  e.g. ['a', 'c#', 'e', 'g'] => A7
  Inversions are indicated using a slash and the root note.
  e.g. ['e', 'g', 'a', 'c#'] => A7 / E
  Chord recognition (for pragmatic reasons) ignores the difference between e.g. 'f#' and 'gb'.
  
  
• Alternatively one can also recognize intervals. Recognition here does take
  into account the difference between e.g. 'f#' and 'gb'.
  e.g. ['c','f#'] => 'augmented fourth' or ['c', 'gb'] => 'diminished fifth'
  
  
• Intervals and chords can be transposed:
  e.g. ['c','e'] transposed to 'f#' => ['f#','a#']
          ['c','e'] transposed to 'gb' => ['gb','bb']
  
  
• For now, internally the library works with note names 'a', 'b', 'c', 'd', 'e', 'f', 'g'
  and modifiers '#' (sharp), 'b' (moll), 'x' (double sharp), 'bb' (double moll)
  

Current features

• PyChoReLib can already recognize and name hundreds of chords.
• New chords can be taught to the system "by example".
  e.g. teach the system that ['c','e','g'] is called 'C', and using its built-in music theory
  knowledge it immediately knows how to recognize and label all major
  chords in all inversions or (more generally) permutations.
  
• Once chord recognition definitions have been taught to the system,
  they can be saved to file, allowing for quick initialization of the recognizer.
• Intervals and chords can be transposed.
  
• PyChoReLib comes with two demo programs:
• test.py: tests the functionality offered by the library using Python's unit testing framework
• midiinputdemo.py: real-time converts midi input from midi devices (ALSA for linux, MME for win32) to chord names
  NOTE: This latter program needs the PyPortMidi software package to be installed and running.
  

Planned features

• Extending the chord recognition database with new chord patterns.
• Build in more music theory knowledge to automatically recognize more chords, while requiring less teaching.
  (Based on matching notes to scales?)
• Add functionality to suggest a scale which can be used to improvise over a chord
• Extensions to the midiinput proof of concept:
• a teach mode in which the system can be taught new chords interactively
  
• a GUI
• proof of concept auto-arranger capabilities
  
• Add support for alternative note names