Introduction to abcMIDI

David Montenegro

Seacoast Linux Users Group

What is abcMIDI?

• a set of utilities for processing ABC music
• part of the ABC Music project http://abc.sourceforge.net/
• tools for typsetting ABC music, converting ABC music to MIDI, creating ABC music from MIDI, and manipulating ABC music files
• developed by James Allwright
• currently maintained by Seymour Shlien (seymour dot shlien at crc dot ca)

What is MIDI?

• Musical Instrument Digital Interface ("MIDI")
• industry standard defined in 1982
• enables electronic musical instruments to communicate with other electronic equipment
• physical interface: DIN 5/180° connectors
• communications protocol: MIDI messages
• file format: Standard MIDI File ("SMF") .MID
• General MIDI Level 1 ("GM") defines specific instruments for each MIDI "Program Number"

What is ABC?

ABC is:

• a format for musical notation as plain text
• developed by Chris Walshaw
• introduced at the end of 1991

Common uses of ABC:

• creating printed sheet music
• generating MIDI for playback/performance
• storing collections of music in tune databases
• Example: JC's ABC Tune Finder

Example ABC file

Mary Had a Little Lamb

X:1
T:Mary Had a Little Lamb
% comment lines start with "%"
M:4/4
L:1/4
K:C
 EDCD | EE E2 | DD D2 | EE E2 |
 EDCD | EE EC | DD ED | C2 z2 |]

According to the official ABC specification: If the file contains only one tune, "X" is optional. "X" immediately preceeds "T". All other fields follow "T". "K" should be the last header field.

Denoting pitch

• Notes are represented by capital or lower case letters A-G, possibly followed by an octave suffix.
• Notes below C5 are represented using capital letters.
• Notes at or above C5 are represented using lower case letters.
• A "," suffix indicates a note one octave lower.
• A "'" suffix indicates a note one octave higher.

ABC staff

						     d'
					       -c'- ----
					    b
				       -a- --- ---- ----
				      g
------------------------------------f-------------------
				  e
--------------------------------d-----------------------
			      c
----------------------------B---------------------------
			  A
------------------------G-------------------------------
		      F
--------------------E-----------------------------------
		  D
---- ---- ---- -C-
	   B,
---- -A,-
 G,

Denoting accidentals

Accidentals may be indicated by an optional prefix.

Examples: ^C _b =f ^c' ^A,

Denoting duration

The duration of a note is indicated by an optional suffix.

• Integers indicate multiples of the default note length.

  Examples: E2 c3 A,4

• A "/" followed by a power of two indicates a fraction of the default note length.

  Examples: a/2 e'/4 b/8

• Omission of a duration suffix indicates the default note length (specified by the header).

  Examples: a' E c A,

The ABC Music "standard"

• official Version 1.6
• draft Version 2.0
• term "standard" used loosely
• syntax not fully specified
• semantics largely unspecified
• the words "must", "mandatory", and "require*" appear nowhere in the official specification
• the draft standard (2.0) is more thorough

abcMIDI component programs

yaps

typesets ABC music as PostScript

abc2midi

creates MIDI files from ABC files

midi2abc

converts MIDI to its approximate ABC representation

abc2abc

transposing ABC music, altering file format, otherwise manipulating ABC music

Typesetting ABC music

Mary Had a Little Lamb

$ yaps mary.abc -o mary.ps

Note: the input file name preceeds any options on the command line.

The result:

Converting ABC music to MIDI

Mary Had a Little Lamb

$ abc2midi mary.abc -o mary.mid

Note: the input file name preceeds any options on the command line.

The result: mary.mid

Transposing ABC music

Start with a simple phrase:

X:1
T:simple phrase to transpose
M:4/4
L:1/4
K:Cmaj
CEGE | CFAF |

$ abc2abc simple.abc -t 7 # filename preceeds options

The result:

X:1
T:simple phrase to transpose
M:4/4
L:1/4
K:Gmaj
GBdB | Gcec |

Note: The key ("K") is now G, as it should be.

Score before and after transposition

Before transposition:

After transposition:

Composing ABC music

ABC be written using any text editor.

X:1
T:Composition 1, Version 1.0 (abridged)
C:David Montenegro
H:Version 1.0 composed 2009-04-21, abridged for abcMIDI presentation
N:range suitable for a 6-hole ocarina
M:4/4
L:1/4
K:C
%%MIDI program 41
CEGE | CFAF | CEGF | EF D2 |
CEGE | CF/2G/2AF | CE/2F/2GF/2D/2 | ED C2 |
% traspose up a major fifth
GBdB | Gc/2d/2ec | GB/2c/2d/2c/2B/2A/2 | ^F/2B/2 E/2A/2 D2 |
GB/2c/2dB | Gc/2d/2e/2d/2c/2B/2 | GB/2c/2dB/2A/2 | BA G2 |
% mix and match
cdec | GB/2c/2dB | CE/2F/2G/2F/2E/2D/2 | B/2e/2 A/2d/2 G2 |
% original key
CE/2F/2GE | C/2E/2F/2G/2A/2G/2F/2E/2 | CE/2F/2GE/2D/2 | ED C2 |]

Example composition

Example MIDI: comp.mid

Contacting the Author

• David Montenegro
  P.O. Box 763
  Farmington, NH 03835
• VirginSnow@vfemail.net