MIRCO

Mirco is a MIDI sequence definition language, it takes midi input and maps simple input notes to more complex patterns. Defined sequences can be parameterised and reused, allowing the easy creation of complex, variative patterns.

This project is still very much a work in progress, all known bugs and problems are marked with "TODO". Feel free to solve any of them and submit a pull request.

Open tasks include (but are not limited to):

• remaining operators (multiplication and division)
• thread safety (use mutexes where needed -> // TODO thread safety)
• make command line parameters declarable in a file
• check the availability of identifiers in a given sequence definition
• parameter error checking
• more ...?

Setup

Install bison and flex.

Arch:

pacman -S bison flex

Compiling:

Run make.

Running:

Run ./mirco examples/syntax1.mirco <args>.

Edit syntax1.mirco!

Command Line Arguments:

--follow-clk

If set mirco will try to match the speed of the incoming midi clock.

Mirco defaults to 24 midi clock pulses per quarter note.

--bpm

Sets beats per minute of the internal output loop. If --follow-clk is specified it will be overridden by the input clock BPM.

Defaults to 120.

--api

Specifies the midi api to be used by RtMidi. Following apis are available to be selected explicitly:

• alsa

• jack

• macosx_core

Linux provides ALSA and JACK apis (assuming they are installed). Note: JACK seems to introduce a lot of latency (500 - 1000ms), use ALSA for the best performance.

MacOs allows for the installation of JACK. If JACK is installed select either jack or macosx_core.

On Windows only one api is available, rendering this argument unnecessary.

WARNING: Currently only linux apis are tested, since both contributors use linux.

--input & --output

Specify the input and output indexes for RtMidi. If the specified index does not exist mirco will wait until it is available. For more control we recommend something like Catia or Claudia

--mcode="..."

If specified, the given string is parsed as a mirco expression and the file can be omitted and is ignored if given.

Syntax

Note:

Notes can be defined with this syntax:

C#3
D3|50
G5:8:2
G#5|100:16

The integer after | specifies the note velocity. Note length and playtime are set after a colon (:). The first integer specifies the note length denominator (:16 for 16ths) and the second integer describes the note play length denominator (:8:2 will play a 16th and wait another 16th after that). Both integers default to 1 if not specified.

Tone Literals:

Tone Literals are only used for arithmetic. They can be defined with the syntax: <octaves>o<semitones>s

1o
2s
3o2s

Chords:

Chords are simultaneously played notes.

(C3, D#3, G3)
(C3, D#3, G3)|100
(C3, D#3, G3):16
(C3, D#3, G3)|50:8:2

Velocity and note length of the individual notes will be ignored and overriden by the chord's parameters.

Realtime Resources:

Realtime resources are sequence nodes which are only known at runtime (for example the note that triggered the playing sequence). They are prefixed with the $ character.

Currently these realtime resources exist:

• $trigger: the note which triggered the sequence.

Sequences:

Sequences can be defined and parameterized as follows:

sequence seq(arg1, arg2) {
    arg1, C4, D4, arg2
}

They can also be defined anonymously:

sequence seq() {
    { F4, C4, D4, G4 } + $trigger
}

Operations:

Sequences and Notes can be subjects to arithmetic:

C2|100 + 2s
(C3, D#3, G3) + 1o
seq(C3, D#3) + 7s

Mappings:

Sequences can be mapped to midi input notes, default (fallback sequences if input note is not mapped) and auto (autoplay).

C4 : seq(F4, D4)
default: seq(G4, D4)
auto: seq(C3, C3)