README

fishnpitch - a JACK MIDI realtime tuner
=======================================

fishnpitch can translate incoming MIDI data to some (micro-tonal)
scale, using pitch bend messages to approximate the frequencies.

Several synthesizers (e.g. Alsa Modular Synth or ZynAddSubFX) already
support this functionality, via .scl and .kbm files produced by the
Scala program. See http://www.huygens-fokker.org/scala/ for a
description of the file formats and a collection of common scales.

The .scl file determines the relative frequencies of notes in a scale
via cent values or ratios. It has to be given as an argument.

The .kbm file is used to specify an alternative keyboard mapping
(e.g. omitting black keys) and set a reference frequency (e.g. key 69
with frequency 440.0 Hz).

Usually, the pitch bend modulation has a range of 200 cents or 2
semitones in both directions. But since some synthesizers
(e.g. amSynth) interprete these values differently, you can specify
the pitch range as an argument, too.

Note that the pitch bend messages are valid for the whole MIDI
channel. To allow for polyphony without corrupting the frequencies, we
have to distribute the notes on many different channels. Normally, all
16 are used, but you can also give your own list of available
channels. For example, "-c 012345678abcdef" doesn't use channel 9,
which is often reserved for percussion. Use this setting with Qsynth.

To install, type
> make

and run the application
> ./fishnpitch SCALE.scl

You should now be able to connect the MIDI ports, e.g., using Qjackctl.

Please report bugs to Robert Schwarz <mail@rschwarz.net>