Guide to writing abc for abc2midi
---------------------------------
(updated June 24 2008 -- drumbars)

The defining document for abc is the abc version 1.6 specification which can 
be found at http://www.gre.ac.uk/~c.walshaw/abc2mtex/abc.txt . This document
is a description of abc as interpreted by abc2midi.

An abc tune consists of a header followed by a body. Each line in the
header is a different field starting with a letter immediately followed 
by : and then the text of the field. The body of the tune contains lines
of music, though it may also contain certain fields. The end of the tune is
marked by a blank line (so blank lines cannot appear within the tune header
or body). 

Comments are allowed in both the header and the body. A comment starts 
with a % sign and continues to the end of the line. A comment may be on 
a line of its own or at the end of a line of abc.

The header should look something like this :

X:1
T:The Rose Tree
M:4/4
L:1/8
Q:1/4=120
K:G

X: is the reference number (each tune in a file should have a unique reference
number). T: is the title of the tune, M: is the time signature, L: is the
unit note length and K: is the key signature. Q: is the tempo field. In
the above example the tempo is given as 120 quarter-notes per minute. X:
must be the first field and K: must be the last field in the header. 

It is advisable to write the fields M:, L: and Q: in that order. The
reason for this is that M: can set up a unit note length which L:
over-rides and the tempo field Q: can be written in other forms that
depend on unit note length. This order makes the meaning clear and
unambiguous. The original abc specification gives a rule for computing
a default value for the unit note length from the M: field. abc2midi
only uses this rule for choosing a unit note length in the header if
the L: field has been omitted.

Other fields may also appear in the header. Common ones are C: composer 
of the tune, D: discography, H: history of the tune, S: source, N: notes, 
Z: transcription note, A: area from which the tune comes, B: book
and R: rhythm. 


Key Signature:

The K: is made up of a base note A-G possibly followed by b for flat or
# for sharp. This specifies a major key. A minor key can be specified
by adding an m while Mixolydian and Dorian modes can be specified by adding
Mix and Dor respectively e.g.

K:Eb
K:EDor
K:EbDor

The following table relates the number of sharps or flats you see on the
stave to what is in the K: field :

7 sharps: C# A#m G#Mix D#Dor
6 sharps: F# D#m C#Mix G#Dor
5 sharps: B  G#m F#Mix C#Dor
4 sharps: E  C#m BMix  F#Dor
3 sharps: A  F#m EMix  BDor
2 sharps: D  Bm  AMix  EDor HP Hp
1 sharp : G  Em  DMix  ADor
0 sharps: C  Am  GMix  DDor
1 flat  : F  Dm  CMix  GDor
2 flats : Bb Gm  FMix  CDor
3 flats : Eb Cm  BbMix FDor
4 flats : Ab Fm  EbMix BbDor
5 flats : Db Bbm AbMix EbDor
6 flats : Gb Ebm DbMix AbDor
7 flats : Cb Abm GbMix DbDor

As an extension, abc2midi also recognizes "Maj" for Major "Min" for Minor,
"Phr" for Phrygian, "Lyd" for Lydian, "Aeo" for Aeolian and "Loc" for
Locrian. Thus CMaj, EPhr, FLyd, AAeo and  BLoc will all generate a stave with 
no sharps or flats. If you use one of these modes in the key signature, it is 
recommended that you add a comment giving the number of sharps or flats for
the benefit of other people who may not be familiar with modes. e.g.

K: DLoc % 3 flats

The key signature may be followed by modifiers. A modifier consists of ^^, ^
=, _ or __ followed by a-g. As an example, ^a means every a should be played
sharp unless otherwise marked in the music. This over-rides whatever has been
set by the key signature. e.g.

K: C ^a

Another extension of the K: field is that it can include a clef specifier
an octave specifier and a transpose specifier e.g.

K:G clef=soprano octave=-1 transpose=-1

The clef is recognized by typesetting programs such as yaps and abc2mps
and in some situations it will cause abc2midi to transpose the notes
up or down by an octave.  Recognized clefs are treble,
bass, baritone, tenor, alto, mezzo and soprano. There are also variants
of these clefs; treble-8, tenor-8,  treble+8  covering ranges which are an
octave below and an octave above the normal treble clef. Other
variants are not recognized at this time. No transposition is
assumed for the bass clef since many abc files enter the notes
with all the commas.

The octave specifier is a convenience to make entering music easier.
It allows the user to avoid repeatedly entering commas  or apostrophes
when entering a sequence of low or high notes. Both yaps and abc2midi
will transpose the notes by the specified number of octaves during 
the parsing stage.

e.g. the passage  B,,, C,, D,, E,, F,, could be written more compactly as

  I:octave=-2
  B, C D E F
  I:octave=0


Some instruments such as the Bb clarinet automatically transpose the
written music. For example in the case of the clarinet, the music is
written in the key of C but the instrument plays it in the key of Bb.
For multivoiced tunes, the %%MIDI transpose indication is not that useful
since it transposes all the voices by the specified amount. The 
transpose=n subcommand in the K: field tells abc2midi to transpose
a particular voice by n semitones without affecting how it appears in
the printed score. For example for the tune,

X:1
T:tranposing
M:1/8
L:2/4
K:C
V:1
K:C transpose=-1
CDEF|GABc|
V:2
K:C
CDEF|GABc
V:1
CDEF|GABc|
V:2
CDEF|GABc

Voice 1 will be played one semitone lower than indicated.
These transposition features are disabled for channel 10 which
is reserved for percussion instruments.


Voice indication:

Many multivoiced abc files now use the V: indication to
specify additional information such as the clef, name of
the voice (to appear in the score). Furthermore, the
V: indication may occur in the header (i.e. before the
first K: indication), for the sole purpose of specifying
such information. Abc2midi, yaps and abc2abc now recognizes
the subfields octave=, clef= and transpose= in the V:
field and treats them in the same manner as if they occurred
in a K: field (as discussed above). Thus the V: field may
appear as
V: 1 clef=treble+8
or
[V: 3 transpose=3]
The V: field is also recognized in both the body and header
of the abc file.  Note that not all abc applications may recognize
these extensions, so you use them at the risk that they may not be 
treated as expected in some cases. Also in the event that
there is a conflicting indication in either the voice or
key signature field, eg.  [V: 1 clef=transpose+8 octave=-1]
the clef indication predominates. 

These transposition features are disabled for channel 10
which is reserved for percussion instruments.



The Body of the Tune
--------------------

Following the header is the tune. This is a textual notation for the things
you might see on a stave :

Notes:

A note consists of a pitch specifier followed by a length. Available pitch
specifiers are :

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

This covers 4 octaves. abc2midi allows lower octaves to be reached by
adding extra , characters and higher octaves to be reached by adding
extra ' characters. However, this is not standard abc and may not be
supported by other abc utilities.

You can raise or lower the pitch specifier a semitone by preceding it with
^ or _ respectively. The key signature and preceding sharps, flats and
barlines modify the default pitch in the same way as on a stave. Preceding 
a note with = generates natural pitch and ^^ and __ can be used for double 
sharp and double flat respectively.

Microtones are indicated by following a ^ or _ with a fraction.
^/C is played as one quarter tone (i.e. half a semitone) above C.
_/C is played as one quarter tone (i.e. half a semitone) below C.
^^/4F is played as 1/4 of a semitone above F#. (The microtone always
follows any accidentals.) In general a microtone offset is indicated
by a fraction using the same convention as note length (described
below). Abcmidi uses the same microtone syntax as abcm2ps.
(See features.txt in the abcm2ps distribution.)

Note that unlike accidentals, microtones do not propagate across a measure.
Microtones are implemented using the MIDI pitchwheel command. Since the
pitchwheel affects all notes played on a specific channel, a microtone
applied to any note in a chord specified by rectangular brackets,
(eg. [ACE]) will apply to all the notes in the chord. Microtone
accidentals override any sharpening or flattening induced by 
key signatures. To illustrate

K: G
^/F F ^^/2F F|

does the following. Even though the key of G major causes F to be
sharp,  the first note is F natural raised by half a semitone.
This effects the next note in making it F natural instead of F#.
The third note is F# raised by a half a semitone. The F#  propagates
to the last note making it also F#.

In accordance to the General MIDI recommendations the pitch range
of the pitchwheel is set to plus or minus two semitones. Therefore
abc2midi cannot go beyond this range.

Microtones may be placed between tied notes, producing a pitch
bend effect. eg G- ^/G.

Microtones have been introduced fairly recently into abcmidi (Mar 2005);
so far there is very little abc notated on the web which exploits
this feature.


The length is in general specified by a fraction following the pitch
specifier. However, the notation is made more concise by allowing much
of the fraction to be omitted.

C  - selects a note of 1 unit note length.
C2 - selects a note of 2 unit note lengths.
C/2 - selects a note of 1/2 unit note length.
C3/4 - selects a note of 3/4 unit note length.

C/ is allowed as an abbreviation of C/2.
C// is allowed as an abbreviation of C/4. However, this is not standard
notation and is not allowed by all abc programs.

No space is allowed within a note, but space may be used to separate
notes in the tune.

Rests are written by using 'z' as the pitch specifier.

z3 - a rest of 3 unit note lengths.

Multiple bar rests can be created using 'Zn' where n is the number of
bars rest required. This is an extension to the standard syntax.

Placing a dot before a note causes it to be played staccato.  (.e)
Placing a M before a note indicates legato. (Me)
Placing a H before a note indicates a fermata.  (He)
Placing a T before a note indicates that this note is trilled.  (Te)
Placing a R before a note indicates that this note is rolled. (Re)

Alternatively you may put !fermata! or !trill! before the
note. Other decorations have not been implemented in this manner.
The fermata may also be applied to a rest, (in order to handle
multivoiced files).

Combining notes

Three notes of the same length can be turned into a triplet by prefixing
them with (3. This has the effect of multiplying the note lengths by 2/3.
A chord can be represented by bracketting the notes together within [ and
] e.g. [a2e2]. An older notation which is also supported is to use + symbols
e.g. +a2e2+. The - symbol can be used to tie together notes of the same 
pitch e.g. a2-a; this is equivalent to a3.

From version 1.4 of abc2midi, the support of tuples and chords is
extended to include general tuple notation (p:q:r , [ and ] for chords
and a more flexible system of interpreting chords.

(p:q:r means play the next r notes at q/p of their notated value. Thus
(3:2:3 is equivalent to an ordinary triplet (3 .

It is possible in abc to write notes of different lengths within a chord
e.g. [ab2] . In this case, abc2midi takes the length of the first note 
(or rest) in a chord is taken as the time before the next note is played. 
However, if the music is to be typeset, this notation should be avoided
because the output will be ambiguous. Instead, the same effect can be
achieved using tied notes e.g. [ab2] c is equivalent to [ab-] [bc]. 
A tie sign is always assumed to belong to the immediately previous note.

A run of 2 or more different notes may be grouped together in a slur.
This usually means that the notes are to be played together as smoothly as
possible. In typeset music, a slur looks very similar to a tie, but in
abc, ( marks the start of a slur and ) marks the end. e.g. (ABc) .
abc2midi recognizes slurs, but they have no effect on the MIDI generated.



Barlines and variant endings

| is an ordinary barline
|| is a double barline
:| is "repeat last section".
|: is "repeat next section".
:: is "repeat last and next sections".
|1 or |[1 or | [1 is "first repeat ending".
:|2 or :|[2 or :| [2 is "second repeat ending".
|[1,3 is first and third ending
:|[2,4 is second and fourth ending
|] and [| are variants of ||.

The notation :: is short for :| followed by |: .

A tune with different ending for the first, second and third repeats has the
general form:

|:  common body of tune  |1  first ending  :|2  second ending :|3 third ending  ||

You may also use this notation to indicate that the first ending is
played on the first and third repeat. For example 

|:common body of tune|1,3  first ending  :|2 second ending  :|4 forth ending|

(The last variant ending should not end with a :|. In other words,
this will not work correctly.  |: ... |[1,2 :|.)

For multivoice abc files, you should be careful that the
different voices share the same repeat structure. When switching
voices (assuming they are interleaved)  abc2midi does not cache 
the repeat state.
 

Printed music commonly misses out a start repeat at the beginning of a tune.
abc2midi will try to fix up things if you miss out a start repeat in single
voice music. Where a tune starts with an anacrusis, abc2midi will always 
fix a repeat to start at the anacrusis rather than the first barline. It is
recommended that you use matching start and end repeats rather than rely on
this behaviour. Missing start repeats are not supported in multiple voice
music. Also, abc2midi does not allow nested repeats. However, you can use 
the more versatile part notation to achieve multiple repeats.

It is not unusual to see music where a repeat does not coincide with the 
end of a bar and the number of beats is not quite correct if the piece is 
played exactly as written. A human player usually knows enough to correct 
the mistake themselves, but abc2midi will play exactly what is written, so 
care needs to be taken that this is corrected when the piece is transcribed
to abc.



Rhythm field and Broken Rhythm Notation
---------------------------------------

R:hornpipe causes notes written in straight time to be played in dotted 
time. The symbol > can be used to achieve a similar effect.

a>b is notated as a3/2b/2 but played as a4/3b2/3.

The symbols < >> << >>> <<< have similar meanings:

a<b   is notated as a/2b3/2 but played as a2/3b4/3.
a>>b  is notated and played as  a7/4b/4.
a<<b  is notated and played as  a/4b7/4.
a>>>b is notated and played as  a15/8b/8.
a<<<b is notated and played as  a/8b15/8.

These times may be adjusted for < and > using the %%MIDI ratio command
described later.

Beware that attempting "advanced" use of these symbols may mean your abc is 
not portable between different abc programs. If the notes on either side of 
the symbol are different lengths, this is reported as an error. If a and 
b are not simple notes, or if there are other complications, then it is 
safer to write the note lengths directly.

Guitar chords :

Anything in quotes is a guitar chord e.g.

"A" "Gm" "B7" "Bm7" "D#aug" "Bbdim7"

Guitar chords must use upper case A-G followed by optional # or b, then
the name of a chord type e.g. "m", "aug", "7". abc2midi currently 
recognizes the following chord names :

 m, 7, m7, maj7, M7, 6, m6, aug, +, aug7, dim, dim7, 9, m9, maj9, M9, 
11, dim9, sus, sus9, 7sus4, 7sus9, 5

You can also add your own; see the %%MIDI chordname command below.

abc2midi automatically generates an accompaniment from the guitar chords.
There are a number of default chord/fundamental rhythms for common time 
signatures which this uses, or you can set up your own. 

Lower case a-g followed by optional # or b will generate a single note,
the fundamental, only.

The chord notation also allows chords such as "G/B" or "G/b". The 
note following the / is interpreted in one of two ways:

If the note following / does not exist as part of the given chord, it
is added to the chord below the root note of the chord (G in the above
example).

If the note following / does exist in the chord, then the notes of the
chord are re-arranged so that it becomes the lowest pitch note of the
chord. This is known as an inversion of the chord. It does not matter
whether the note following the / is upper or lower case. They are
both treated the same.

This notation has been extended so that finger numbers "1" "2" "3", 
"4" or "5" are allowed. abc2midi ignores these, but a typesetting
program might support them.

You may find some abc tunes that abuse this notation and use quotes 
for things that are not guitar chords. Usually these are
tunes which have been typeset but never played by a computer. If you 
don't want to just delete things in quotes, you can insert one of the 
characters _, ^, @, < or > after the first quote e.g. "_Chorus" 
"_Very Loud". This causes abc2midi to ignore the following text. However, 
typesetting programs should recognize the first character as telling
them where to print the following text.

Another extension is to allow musical instructions to appear in exclamation
marks e.g. !pizzicato! abc2midi currently supports the following :
    !ppp! !pp! !p! !mp! !mf! !f! !ff! !fff!
Default volume is equivalent to !f!. In both the " " and ! ! fields, 
abc2midi allows multiple terms separated by semi-colons e.g. "Am;1".

The !breath! instruction causes the note to be played half length
followed by a rest of half its length (just like staccato).

The !arpeggio! instruction affects the next chord and introduces
a larger delay between the onset of each note in the chord. (See
the text preceding %%MIDI chordattack in this file for more 
explanations.)

The !crescendo(! and !crescendo)! delineate the start and
end of a crescendo. Alternatively, you can use !<(! and !<)!.
Abc2midi does not implement a gradual loudness increase,
but instead increases the loudness at the start and end
of the crescendo by a fixed amount. (See %%MIDI beatmod
and %%MIDI deltaloudness for more information.)

The !diminuendo(! and !diminuendo)! behave similarly but
reduce the loudness. These instructions have not been
implemented in yaps.

A line of music may contain any number of notes, barlines and guitar
chords. Spaces may be used to separate these.

Some abc fields may appear within the body of the abc tune :

K: - change key
L: - change unit note length
M: - change meter
Q: - change tempo
P: - part label
V: - voice label
w: - words to be matched syllable by syllable to notes

Each field must be on a line by itself. 

Part Notation
-------------

A part label must be a single character in the range A - Z. e.g.

P:A

A parts specifier in the header can be used to define the MIDI output as
some combination of the specified parts e.g.

P:ABACABA

You can use (  )<number> to repeat a part a specified number of times
e.g. P:A(AB)6 is equivalent to P:AABABABABABAB. If there are no brackets,
just the last part is repeated, so P:AAB3 is equicalent to P:AABBB. Dots
may be inserted into the part specifier to make it easier to read
e.g P:A.AB.AC

If there is no parts specifier, the output is simply the parts (or just
the unlabelled music) in the order in which it appears in the tune body.

You may if you wish have multiple voices sounding concurrently within each
part. These are indicated with V:N to indicate voice number N.

e.g.

V:1
<music for voice part 1>
V:2
<music for voice part 2>
and so on.

A part label implicitly starts with V:1, as does the K: field which starts
the tune body, so you are not allowed to place a part label within a voice. 
The duration of each of the voice parts must be the same for them to 
synchronize correctly; abc2midi will warn you if they are not! From version 
1.7 onwards, abc2midi allows any voice apart from voice 1 to be completely 
omitted from a part.

If no V: field appears after the first K:, whatever follows is assumed to
belong to voice 1 (the default voice). The V: field is an extension to 
abc 1.5. 

The lines between one V:N field and the next V: field define a region 
belonging to voice N. Within a part, you may have more than one such
region for each voice. The music for voice N within a part is all 
the voice N regions taken in sequence.

The M:, L: and K: fields in the header apply to all voices. After
the header, these fields apply only to the voice in which they appear.
In previous versions of abc2midi, an L:, for example, would affect 
everything after it appeared up until the next L:, regardless of what
voice changes there were.

The Q: tempo field should only appear in voice 1 and applies to all voices.

The U: abbreviation field has limited use here. You can specify
an abbreviation such as
U: P = !trill!
and then in the body, eg. |DGAPF|, P will be replaced with !trill!
Only letters between H and Z can be used. Furthermore, you can
not redefine reserved letters such as H (fermata), L (unit length),
M (mordent) , R (roll) , T (trill).


Adding Lyrics to a Tune
-----------------------

The W: field (upper case W) can be used for lyrics to be typeset separately
if the abc is printed out. The w: field (lower case w) in the body of a tune 
supplies a line of lyrics to be matched syllable by syllable to the last line 
of notes. These are usually printed below the notes if the abc is typeset.  
abc2midi uses these to generate karaoke MIDI files. A karaoke MIDI file can
only contain one set of lyrics; abc2midi will generate a warning if the abc 
file contains multiple voices with lyrics in. When the karaoke MIDI file 
is played using an appropriate player program, the lyrics appear on the screen 
with the current syllable highlighted. Within the lyrics, the following 
symbols may be used :

<space> break between words
-       break between syllables within a word
|       advance to next bar
_       indicates last syllable is to be held for another note
*       indicates a one note rest for the singer.
~       appears as a space but connects syllables each side into one.
\-      appears as - in the output
\       continuation character. Next w: field is part of the same line.

A rest is not matched by any lyrics.
A tied note e.g. d2-d2 is treated as 2 notes (or however many parts it
is written as), despite the fact that it only plays as a single note.

abc2midi ignores space characters if they occur either (a) between the 
end of a word/syllable and a hyphen or underscore or (b) between a hyphen or 
underscore and the beginning of a word/syllable. However, some software 
incorrectly treats a hyphen as a separate word if there is a space between 
it and the previous syllable, so, for example, you should write go-ing and 
not go - ing to ensure that your abc is portable between programs.

The following example illustrates most of these :

 gf|e2dc B2A2|B2G2 E2D2|.G2.G2 GABc|d4 B2
w: Sa-ys my au-l' wan to your aul' wan\
w: Will~ye come to the Wa-x-ies dar-gle?

Note that the continuation character is used in a rather strange manner.
One w: field and all continuations will match one line of music, whether
or not the line of music ends with a continuation character. You can
think of the \ in a music line dividing that line into sections and \
in a w: field further dividing these section into sub-sections.

It is possible for a music line to be followed by several w: fields.
This can be used together with the part notation to create verses.
The first w: field is used the first time that part is played, then
the second and so on. If the tune uses repeats, these must be placed
at the end of a line of music in order to make sure that the start of
a w: field matches up with the repeat.

abc2midi-specific commands (%%MIDI)
------------------------------------

abc2midi supports a number of commands of the form

%%MIDI command

Each of these should appear on a line by itself; however there
is now provision to pass the MIDI command in an inline I: field
(see CHANGES file, March 25 2005 entry.)  All of them are allowed 
within the abc tune body. By using these in combination with the part 
notation, one can, for example, play a part transposed or in a different key.

The idea behind this syntax is that other programs will treat it as a
comment and ignore it.

%%MIDI channel n

selects melody channel n (in the range 1-16).

%%MIDI program [c] n

selects program n (in the range 1-128) on channel c. If c is not given, the
program is selected on the current melody channel. Most modern tone
generators follow the General MIDI standard which defines the instrument 
type for each program number. These instrument types are listed at the end
of this document. Note that for multivoiced files, the program command
is placed in the track associated with the voice previously declared.
If the %%MIDI indications affect channels in other tracks, it is
recommended that they are placed in the first track or first declared voice.
See the note in the CHANGES file for the date January 1 2005.


%%MIDI beat a b c n

controls the way note velocities are selected. The first note in a bar has
velocity a. Other "strong" notes have velocity b and all the rest have velocity
c. a, b and c must be in the range 0-127. The parameter n determines which
notes are "strong". If the time signature is x/y, then each note is given
a position number k = 0, 1, 2 .. x-1 within each bar. Note that the units for
n are not the unit note length. If k is a multiple of n, then the note is 
"strong". The volume specifiers !ppp! to !fff! are equivalent to the 
following :

!ppp! = %%MIDI beat 30 20 10 1
!pp!  = %%MIDI beat 45 35 20 1
!p!   = %%MIDI beat 60 50 35 1
!mp!  = %%MIDI beat 75 65 50 1
!mf!  = %%MIDI beat 90 80 65 1
!f!   = %%MIDI beat 105 95 80 1
!ff!  = %%MIDI beat 120 110 95 1
!fff! = %%MIDI beat 127 125 110 1

%%MIDI beatmod n
increments by n (or decrements if n is negative) the velocities a, b and
c described above. It is also used in implementing crescendo and
diminuendo (eg. !<(!, !crescendo(! etc.)


%%MIDI nobeataccents

For instruments such as church organ that have no greatly emphasized beat
notes,
using this will force use of the 'b' velocity (see %%MIDI beat)
for every note irrespective of position in the bar.  This allows dynamics
(ff, f, etc) to be used in the normal way.

%%MIDI beataccents

Revert to emphasizing notes the the usual way. (default)


%%MIDI deltaloudness n
where n is a small positive number.  By default the crescendo and 
dimuendo instructions modify the beat variables a, b, and c by
15 velocity units. This instruction allows you to change this default.

%%MIDI beatstring <string of f, m and p>

This provides an alternative way of specifying where the strong and weak
stresses fall within a bar. 'f' means velocity a (normally strong), 'm' 
means velocity b (medium velocity) and 'p' means velocity c (soft velocity).
For example, if the time signature is 7/8 with stresses on the first, fourth 
and sixth notes in the bar, we could use the following 

%%MIDI beatstring fppmpmp


%%MIDI transpose n

transposes the output by the specified number of semitones. n may be
positive or negative.

%%MIDI rtranspose n

Relative transpose by the specified number of semitones. i.e. 
%%MIDI transpose a followed by %%MIDI rtranspose b results in a
transposition of a+b. %%MIDI transpose b will result in a transposition
of b semitones, regardless of any previous transposition.

%%MIDI c n

specifies the MIDI pitch which corresponds to c. The default is 60. This
number should normally be a multiple of 12.

%%MIDI grace a/b

sets the fraction of the next note that grace notes will take up. a
must be between 1 and b-1. The grace notes may not sound natural
in this approach, since the length of the individual grace notes
vary with the complexity of the grace and the length of the
following note. A different approach (which is now the default)
assumes that the grace notes always have fixed duration specified
by a fraction of the unit length. To use the other approach
you would specify,

%%MIDI gracedivider b

where b specifies how many parts to divide the unit length
specified by the L: field command. For example if b = 4 and
L: = 1/8, then every grace note would be 1/(8*4) or a 32nd
note. Time would be stolen from the note to which the grace
note is applied. If that note is not long enough to handle
the grace then the grace notes would be assigned 0 duration.

%%MIDI chordname name n1 n2 n3 n4 n5 n6

Defines how to play a guitar chord called "name". n1 is usually 0 and
n2, n3 to n6 give the pitches of the other notes in semitones relative
to the root note. There may be fewer than 6 notes in the chord, but not 
more.If "name" is already defined, this command re-defines it. Unlike 
most other commands, chordname definitions stay in effect from where they 
are defined to the end of the abc file. The following illustrates how
m, 7, m7 and maj7 could be set up if they were not already defined.
%%MIDI chordname m 0 3 7
%%MIDI chordname 7 0 4 7 10
%%MIDI chordname m7 0 3 7 10
%%MIDI chordname maj7 0 4 7 11

%%MIDI gchord string

sets up how guitar chords are generated. The string is a sequence made of
of z's, c's f's and b's for rests, chords,  fundamental and fundamental
plus chord notes respectively. This specifies how each bar is to be played.
An optional length is allowed to follow the z's, c's, f's and b's  e.g. czf2zf3.
If the abc contains guitar chords, then abc2midi automatically adds chords and
fundamentals after encountering the first guitar chord. It keeps using that
chord until a new chord is specified in the abc. Whenever the M: field is
encountered in the abc, an appropriate default string is set :

For 2/4 or 4/4 time default is equivalent to :
%%MIDI gchord fzczfzcz

For 3/4 time default is equivalent to :
%%MIDI gchord fzczcz

For 6/8 time default is equivalent to :
%%MIDI gchord fzcfzc

For 9/8 time default is equivalent to :
%%MIDI gchord fzcfzcfzc

Please note, that the default gchord string is reissued any
time a time signature change is specified in the body of the music.
This means if one of the bars has an extra beat you included
a M: declaration before and after the measure, the gchord string
would be reset to the default string for that time signature
and not the one that you had declared. It is necessary for
you to send another %%MIDI gchord declaration after the
the time signature in order to set this back the way you want
it. This is one of the changes introduced into abc2midi so
that the accompaniment track always follows the meter of the
music for the regular time signatures.

The gchord command has been extended to allow you to play
the individual notes comprising the guitar chord. This allows
you to play broken chords or arpeggios. The new codes g,h,i,j,
G,H,I,J reference the individual notes starting from the
lowest note of the chord (not necessarily the root in the
case of inverses). For example for the C major chord, g
refers to C, h refers to E and i refers to G. For a gchord
command such as,

%%MIDI gchord ghih

Abc2midi will arpeggiate the C major guitar chord to
CEGE. The upper case letters G,H,I, and J refer to
the same notes except they are transposed down one
octave. Note for the first inversion of the C major 
chord (indicated by "C/E"), E would be the lowest
note so g would reference the note E.

Like other gchord codes, you may append a numeral indicating
the duration of the note. The same rules apply as before.
You can use any combination of the gchord codes,
(fcbghijGHIJz).


%%MIDI chordprog n

Sets the MIDI instrument for the chords to be n.

%%MIDI bassprog n

Sets the MIDI instrument for the bass notes to be n.

%%MIDI chordvol n

Sets the volume (velocity) of the chord notes at n.

%%MIDI bassvol n

Sets the volume (velocity) of the bass notes at n. There is no corresponding
melodyvol command since there are 3 velocity values for melody, set using the
beat command.

%%MIDI gchordon

Turns on guitar chords (they are turned on by default at the start of a
tune).

%%MIDI gchordoff

Turns off guitar chords.

%%MIDI fermatafixed
Directs abc2midi to expand a fermata by one unit length.
Thus HC3 becomes C4.

%%MIDI fermataproportional
This is the default. A fermata doubles the length of a
note so HC3 becomes C6.

%%MIDI droneon

This turns on a continuous drone used in bagpipe music. The
drone consists of two notes (by default A, and A,,) played
on a bassoon at a MIDI loudness (velocity) 80. If you
can configure the drone sound using the %%MIDI drone command
described below.

%%MIDI droneoff

This turns off the drone.

%%MIDI drone n1 n2 n3 n4 n5

Configures the drone chord. n1 = MIDI program,
n2 = MIDI pitch 1, n2 = MIDI pitch 2, n4 = MIDI velocity 1, 
and n5 = MIDI velocity 2. By default they have already
been set to 70 45 33 80 80.



%%MIDI drum string [drum programs] [drum velocities]

This sets up a drum pattern. The string determines when there is a drum beat
and the drum program values determine what each drum strike sounds like.

e.g. %%MIDI drum d2zdd 35 38 38  100 50 50

The string may contain 'd' for a drum strike or 'z' for a rest. By default
a voice starts with no drum pattern. Like gchord, a command
 
%%MIDI drumon

is needed to enable the drumming. The drum pattern is repeated 
during each bar until a

%%MIDI drumoff

is encountered. The %%MIDI drum command may be used within a tune
to change the drum pattern. This command places the drum sounds on 
channel 10 and assumes your tone generator complies with the 
General Midi standard - if it does not, then you may hear tones 
instead of drum sounds. (Note the old method of using the
instruction !drum! and !nodrum! is being deprecated.)

In both the gchord and drum commands, the standard note length of
a single note f,c,z or d is not set by the L: command. Instead it
is adjusted so that the entire gchord string or drum string fits
exactly into one bar. In other words the duration of each note
is divided by the total duration of the string. This means that, 
for example, the drum string "dd" is equivalent to drum string "d4d4".
You cannot currently specify fractions directly (eg. C3/2)
as done in the body of the music, but it is still possible to express
complex rhythms. For example, to indicate a rhythm such as
(3ddd d/d/d/d, you would write the string "d4d4d4d3d3d3d3".

For reference, the percussion instruments defined in the General MIDI 
standard are given below.

35  Acoustic Bass Drum  59  Ride Cymbal 2
36  Bass Drum 1         60  Hi Bongo
37  Side Stick          61  Low Bongo
38  Acoustic Snare      62  Mute Hi Conga
39  Hand Clap           63  Open Hi Conga
40  Electric Snare      64   Low Conga
41  Low Floor Tom       65   High Timbale
42  Closed Hi Hat       66  Low Timbale
43  High Floor Tom      67  High Agogo
44  Pedal Hi-Hat        68  Low Agogo
45  Low Tom             69  Cabasa
46  Open Hi-Hat         70  Maracas
47  Low-Mid Tom         71  Short Whistle
48  Hi Mid Tom          72  Long Whistle
49  Crash Cymbal 1      73  Short Guiro
50  High Tom            74  Long Guiro
51  Ride Cymbal 1       75  Claves
52  Chinese Cymbal      76  Hi Wood Block
53  Ride Bell           77  Low Wood Block
54  Tambourine          78  Mute Cuica
55  Splash Cymbal       79  Open Cuica
56  Cowbell             80  Mute Triangle
57  Crash Cymbal 2      81  Open Triangle
58  Vibraslap    

Note you are able to change this mapping using the
the MIDI command %%MIDI drummap described below.


%%MIDI drummap note midipitch

where the pitch of the note is notated using abc notation
and midipitch is a number between 35 and 81 inclusive referring
to the above table. This command is used if you
are notating a drum track, i.e. a voice played on 
channel 10. Rather than being forced to use the note
corresponding to the desired percussion instrument, (for
example C (MIDI pitch 60) for hi bongo, you can use can
change the mapping to use a more convenient pitch.
for example to access bass drum 1 (MIDI pitch 36) you
would require the note C,, which is awkward to display
in common music notation. You can change the mapping to
say _D using
%%MIDI drummap _D 36.

An example is provided in the file CHANGES (November 6 2005).


%%MIDI drumbar n

The %%MIDI drum line can sound quite monotonous if it is repeated
each bar. To circumvent this problem a new MIDI command
%%MIDI drumbars n
where n is a small number will spread out the drum string over
n consecutive bars. By default drumbars is set to 1 maintaining
compatibility with existing abc files. You should take
care that the drumstring is evenly divisible between the
drumbar bars. Also the time signature should not change
between bars in a drumbar unit. (Sample abc file in CHANGES
June 24 2008.)



%%MIDI control [bass/chord] n1 n2 

This generates a MIDI control event. If the word "control" is followed by
"bass" or "chord", the event will be applied to the bass or chord channel,
otherwise it will be applied to the current channel. n1 and n2 are numbers
in the range 0-127. Generally, n1 selects a control parameter and n2 is
the value to which it is set. A couple of examples :

%%MIDI control 7 50

will set the main volume of the channel to 50

%%MIDI control 10 0

will set the pan parameter (left/right balance) to 0.

See the manual for your MIDI tone generator to find out what control events 
are supported.

%%MIDI portamento [bass/chord] n

This will turn on the MIDI portamento controller and set the speed
of sliding between pitches to n. Like %%MIDI control, if the word
portamento is followed by "bass" or "chord", the event will be 
applied to the bass or chord channel, otherwise it will be 
applied to the current channel. The parameter n should be between
0 and 63. Large values imply a slow transition between pitches.
I have found the resulting effect to be rather wierd, especially
for large pitch intervals.

%%MIDI noportamento [bass/chord] 

This will turn off the portamento controller (current default).

%%MIDI pitchbend [bass/chord] <high byte> <low byte>

This generates a pitchbend event on the current channel, or on the bass
or chord channel as specified. The value given by the following two bytes
indicates the pitch change.

%%MIDI nobarlines

This is a somewhat obscure option to support early music without barlines.
Normally, an accidental applied to one note e.g. ^c will apply to every note
at the same point in the scale until the end of the bar (so C,, C, C c c'
would all be sharpened). This option turns off this behaviour, so that an
accidental applies only to the next note. It should be used in the header of
any tune requiring this behaviour.

%%MIDI barlines

This turns off the effect of %%MIDI nobarlines in the middle of a tune. This
is the default behaviour assumed at the start of every tune.

%%MIDI ratio n m

This sets the ratio of note lengths in broken rhythm (e.g. a>b).
The default behaviour is for note a to sound for twice as long as note b.
This can be achieved with

%%MIDI ratio 2 1

and hornpipes are commonly played with approximately this ratio. However,
for other musical styles, a different ratio may be appropriate. If you
are using abc2midi to export music to another program for printing, then
you may wish to use a ratio of 3:1 which is how hornpipes are usually
notated. This can be achieved with

%%MIDI ratio 3 1


Arpegiation:

With version 1.54 Dec 4 2004 of abc2midi, notes in chords
(eg. [FAc]) are not played in the same instant but offsetted
and shortened by 10 MIDI time units. Thus the first note
in the chord (eg. F) is played for the full indicated time,
the second note (eg. A) starts 10 MIDI units later and is shortened
by the same amount and the third note starts another 10 MIDI
units later and is shortened by another 10 units. This introduces
an "expressivo" option and avoids the heavy attack. (This
does not apply to gchords or multivoiced chords.) The amount
of the delay and shortening may be configured by the MIDI command

%%MIDI chordattack n

where n is a small number. If n is zero, then abc2midi should
behave as in earlier versions. The delay n is in MIDI time units
where there are 480 units in a quarter note beat. The program
may not run correctly if n is too large and there are short
chords.

%%MIDI randomchordattack n

where n is a small number. This is similar to above, except the
delay of each note in the chord varies randomly between 0 and n-1.
Therefore each chord is played differently.


Articulation:

%%MIDI trim x/y

where x and y are two numbers. This command controls the articulation
of notes and chords by placing silent gaps between the notes.  The length
of these gaps is determined by x/y and the unit length specified by the L:
command. These gaps are produced by shortening the notes by the same amount.
If the note is already shorter than the specified gap, then the gap
is set to half the length of the note.  The fraction x/y indicates 
a note duration in the same manner as specified in the abc file.
The actual duration is based on the unit length specified by the
L: field command. It is recommended that x/y be a fraction close
to zero. The denominator, y does not need to be a power of 2.
Trimming is disabled inside slurs as indicated by parentheses.

You can turn off all note trimming by setting x to 0,
eg 0/1. By default, note trimming is turned off at the beginning
of a tune or voice command.




To avoid the problem of breaking up a music line
in order to place a %%MIDI command, for example, 
A2 B2|\
%%MIDI drumon
C2 D2|
you can place the MIDI instruction inside an info field
using the following syntax.

A2 B2|[I:MIDI= drumon] C2 D2|

The '=' following the MIDI is very important. The info field
syntax allows you to place several MIDI commands in one inline
block, for example
[I: MIDI = program 73 MIDI=chordprog 29]
(Spaces are optional.)
Other examples can be seen in the file CHANGES in the
following the March 25 2005 entry.



%%MIDI temperamentlinear octave_cents fifth_cents

This command allows you to change the temperament of the 
scale. Octave_cents specifies the size of an octave
in cents of a semitone or 1/1200 of an octave. Fifth_cents
specifies in the size of a fifth (normally 700 cents).
For example:
%%MIDI temperament 1200.5 698.0
will produce a slightly stretched scale with narrowed fifths.

More details on linear tempered scales can be found 
on the site
http://www.xs4all.nl/~huygensf/scala/
The pitch of each note is modified using a MIDI pitchbend
command to comply with the scale. In order to handle chords,
each note of the chord must be played on a different MIDI
channel.

The normal musical scale has a temperament of
%%MIDI temperamentlinear 1200 700

but to avoid unnecessary pitchbends you should restore
to the normal temperament using the  command
%%MIDI termperamentnormal



%%MIDI makechordchannels n

If you are not modifying the temperament or inserting
microtones you can ignore this command.  Normally
in voice chords containing microtones e.g. [_/CE_/G] 
will not be handled correctly because all the notes in the
chord are played on the same MIDI channel. If you include
the above command where n here is 2, then two separate channels
will be allocated for playing the other two notes in this chord.
These separate channels will be used whether the pitches
of the notes are bent or not. Once you allocate those channels
with this command, they are no longer available and since
there are only 16 MIDI channels you can easily run out.
Furthermore, you need to allocate chordchannels for any
other voices which may have in voice chords. The channel
allocation process will automatically propogate the program
assignment (musical instrument) to the other chordchannels,
so be sure you set the program before using this command.
If you need to change the program assignments, you can
find out the channel numbers that were assigned by running
abc2midi in verbose mode using the -v command. 




Global settings for abc2midi
----------------------------

If you are creating an abc file with many tunes, abc2ps and abcm2ps
allows you to declare certain settings that apply to all tunes
by placing them at the beginning of the file prior to the
start of the tune. Abc2midi provides this feature but presently
only to a limited extent. The following MIDI commands will
change the defaults for all tunes if they are placed outside
of any tune.

%%MIDI C ...
%%MIDI nobarlines ...
%%MIDI barlines ...
%%MIDI fermatafixed 
%%MIDI fermataproportional
%%MIDI ratio ...
%%MIDI chordname ...
%%MIDI deltaloudness ...

All other MIDI commands placed outside of a tune will be
ineffective and return a warning message

"cannot handle this MIDI directive here"

(For more details see CHANGES, May 06 2005 entry.)

Any of these defaults can be changed as many times as you like
provided that they are occur outside a tune which is usually
delineated by a X: reference number and a blank line.

Voice Splitting
---------------

Abcm2ps allows a voice to separate into two or more voices
in a specific bar using the symbol '&'. This feature
now works in abc2midi. Abc2midi places the split voice
into a separate MIDI track with intervening rests.
When a voice splits, the new voice inherits the program
number (musical instrument) from the parent voice.


Compatibility with proposed abc standard version 2.0
----------------------------------------------------

The proposed standard introduces a new copyright field
using the syntax

%%abc-copyright (c) Copyright John Smith 2003

Abc2midi now inserts this in the MIDI file in the form of a
metatext copyright tag. Changes were made to the event_specific
function in store.c to process the copyright information. It
is also copied into the Karaoke track (if it is created) as
as @T field.




Typesetting abc
---------------
If you want to typeset your abc, there are some more features of abc syntax
that you need to know:

If 2 notes appear consecutively with no space between them, they will be
grouped together under the same beam. A space between them prevents them
sharing a beam.

A new line of stave music is generated by the newline at the end of a 
line of abc music. To suppress this, put a \ character at the end of the 
abc music line.

An abc music line should end either at a bar line or at the space
between two notes which indicates they do not share a beam. This is true
whether or not the abc line ends with a \ character.

Error Messages and Warnings
---------------------------

abc2midi attempts to perform various checks on the abc and
reports any problems via error and warning messages:

A warning message indicates there is something strange in the abc - 
possibly an error or possibly non-standard usage.

An error message means that abc2midi thinks there is definitely an 
error in the abc and the MIDI generated may not be correct.

In a small number of cases, an error may cause abc2midi to stop.
This is usually either because it has run out of memory or because
there is some problem with reading or writing a file.



Bar counting and checking
-------------------------

Conventionally bars are numbered starting from one. If the first
bar is incomplete (anacrusis), then it is counted as zero.
Abc2ps and abcm2ps follows this convention but abcMIDI does not.
All bars are counted starting from zero and furthermore if there
is an incomplete bar just before a repeat (:| |: or ::), the
bar count is not incremented. It is difficult to change this
convention since abcMIDI assigns a number to the bar ahead
when it sees a bar line. It would be necessary to introduce
some look ahead for the first bar in the tune.

If abc2midi reports a problem in a specific bar, you can use
yaps with the -k option (for print bar numbers) to locate this
bar. If you use another program such as abc2ps, then the bar
number in the displayed or printed version may be one unit
higher.

The most common error seems to be a missing beat or having
an extra beat in a bar. In the vicinity of a repeat, abc2midi
tries to complete the first bar using the incomplete bar at
the end of the repeat. If the first bar can be completed, then
no warning is reported. The first bar may be complete the first
time the section is played but incomplete in the second repeat. 
Complications occur when the left repeat symbol (|:) is
missing and abc2midi has to assume it is at the beginning.
More complications occur when there is a key change after
the repeat or the music is split into parts A,B,C, etc.
Yaps does the bar checking differently when it encounters
repeats so that it may not resolve as many incomplete bars
and report more warnings.

The bar checking is present for providing warnings. For some
music, an extra beat may be intentional and it is not
marked by a meter change. If you are only printing the
music, there is probably no problem; however, if you are
producing a MIDI file and there is guitar (gchord) accompaniment
then a break or missing beat might be noticeable.



General MIDI Program Number/Instrument Name
-------------------------------------------

 1. Acoustic Grand Piano
 2. Bright Acoustic Piano 
 3. Electric Grand Piano
 4. Honky-tonk Piano 
 5. Electric Piano 1 
 6. Electric Piano 2 
 7. Harpsichord 
 8. Clavi 
 9. Celesta 
 10. Glockenspiel 
 11. Music Box 
 12. Vibraphone 
 13. Marimba 
 14. Xylophone 
 15. Tubular Bells 
 16. Dulcimer 
 17. Drawbar Organ 
 18. Percussive Organ 
 19. Rock Organ 
 20. Church Organ 
 21. Reed Organ 
 22. Accordion 
 23. Harmonica 
 24. Tango Accordion 
 25. Acoustic Guitar (nylon) 
 26. Acoustic Guitar (steel) 
 27. Electric Guitar (jazz) 
 28. Electric Guitar (clean) 
 29. Electric Guitar (muted) 
 30. Overdriven Guitar 
 31. Distortion Guitar 
 32. Guitar harmonics 
 33. Acoustic Bass 
 34. Electric Bass (finger) 
 35. Electric Bass (pick) 
 36. Fretless Bass 
 37. Slap Bass 1 
 38. Slap Bass 2 
 39. Synth Bass 1 
 40. Synth Bass 2 
 41. Violin 
 42. Viola
 43. Cello 
 44. Contrabass 
 45. Tremolo Strings 
 46. Pizzicato Strings 
 47. Orchestral Harp 
 48. Timpani 
 49. String Ensemble 1 
 50. String Ensemble 2 
 51. SynthStrings 1 
 52. SynthStrings 2 
 53. Choir Aahs 
 54. Voice Oohs 
 55. Synth Voice 
 56. Orchestra Hit 
 57. Trumpet 
 58. Trombone 
 59. Tuba 
 60. Muted Trumpet 
 61. French Horn 
 62. Brass Section 
 63. SynthBrass 1 
 64. SynthBrass 2 
 65. Soprano Sax
 66. Alto Sax 
 67. Tenor Sax 
 68. Baritone Sax 
 69. Oboe 
 70. English Horn
 71. Bassoon 
 72. Clarinet 
 73. Piccolo
 74. Flute 
 75. Recorder 
 76. Pan Flute
 77. Blown Bottle
 78. Shakuhachi 
 79. Whistle 
 80. Ocarina 
 81. Lead 1 (square) 
 82. Lead 2 (sawtooth)
 83. Lead 3 (calliope) 
 84. Lead 4 (chiff) 
 85. Lead 5 (charang) 
 86. Lead 6 (voice) 
 87. Lead 7 (fifths) 
 88. Lead 8 (bass + lead)
 89. Pad 1 (new age)
 90. Pad 2 (warm) 
 91. Pad 3 (polysynth)
 92. Pad 4 (choir) 
 93. Pad 5 (bowed) 
 94. Pad 6 (metallic) 
 95. Pad 7 (halo) 
 96. Pad 8 (sweep) 
 97. FX 1 (rain) 
 98. FX 2 (soundtrack) 
 99. FX 3 (crystal) 
 100. FX 4 (atmosphere) 
 101. FX 5 (brightness) 
 102. FX 6 (goblins) 
 103. FX 7 (echoes) 
 104. FX 8 (sci-fi) 
 105. Sitar 
 106. Banjo 
 107. Shamisen 
 108. Koto 
 109. Kalimba 
 110. Bag pipe 
 111. Fiddle 
 112. Shanai 
 113. Tinkle Bell 
 114. Agogo 
 115. Steel Drums 
 116. Woodblock 
 117. Taiko Drum 
 118. Melodic Tom 
 119. Synth Drum 
 120. Reverse Cymbal 
 121. Guitar Fret Noise 
 122. Breath Noise 
 123. Seashore 
 124. Bird Tweet 
 125. Telephone Ring 
 126. Helicopter 
 127. Applause 
 128. Gunshot

---------------------------------------------------------------------
This reference written 1995-1998 by James Allwright 
