Guide to writing abc for abc2midi

abc2midi guide .. abc cheatsheet
Fiddle Runtime .. Fiddle Resources
Extending Fiddle .. Installing Fiddle
General MIDI .. MIDI CC .. MIDI notes
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Audio Troubleshooting

DbAbc was built from a C++-port of the abcmidi open-source project. Some modifications and enhancements can be found in the ported version. That said, most of the capabilities in DbAbc originated in abc2midi and so this document, originally abcguide.txt, may be of value to DbAbc users.

Please note: our target with this work was to use abc within ChucK. This target affects the testing prioritization plan. The changes to achieve reentrancy were substantial and new bugs are likely to have been introduced. Buyer beware…

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Overview

The abc notation language is described by the version 1.6 specification document and later modifications to this document referred to as version 2.1 and version 2.2. These can be found at abcnotation.com.

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: overrides 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.

Tempo

The tempo is usually indicated with the Q: field command, eg. Q:1/4=180 which is interpreted as 180 quarter beats per minute. In compliance with the abc standard 2.0, you may also indicate the tempo using directives such as "lento", "allegro", "vivace" etc.

The following table based on the musicdictionary was used to translate the indications:

name rate
Larghissimo 1/4=40
Adagissimo 1/4=44
Lentissimo 1/4=48
Largo 1/4=56
Adagio 1/4=59
Lento 1/4=62
Larghetto 1/4=66
Adagietto 1/4=76
Andante 1/4=88
Andantino 1/4=96
Moderato 1/4=104
Allegretto 1/4=112
Allegro 1/4=120
Vivace 1/4=168
Vivo 1/4=180
Presto 1/4=192
Allegrissimo 1/4=208
Vivacissimo 1/4=220
Prestissimo 1/4=240

Note: case is ignored (eg. ALLEGRO Allegro or allegro are treated the same). The directive must be enclosed in double quotes.

Reference: http://abc.sourceforge.net/standard/abc2-draft.html#Q:%20-%20tempo

Examples
X:1
T:tempo
M:2/4
L:1/4
K:G
Q: "Adagio"
CD|EF|
Q: "Adagio" 1/4=40
GA|Bc|

In the second tempo command, the 1/4=40 overrides the default 1/4=59.

The symbols M:C and M:C| give common time (4/4) and cut time (2/2) The symbol M:none omits the meter entirely (free meter). It is also possible to specify a complex meter, e.g. M:(2+3+2)/8, to make explicit which beats should be accented. The parentheses around the numerator are optional.

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, ^g means every a should be played sharp unless otherwise marked in the music. This adds ^g to the existing key signature. For example

K: G ^c^g

will produce a key signature similar to A major. Following the abc draft 2.0 standard, inserting the string exp in the key signature will cause abc2midi to override the existing key signature. Thus

K: A exp _b

will remove the f,c and g sharps and put a b-flat instead. You may use both upper and lower case letters as key modifiers since they are distinguished by abcm2ps.

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.

Clefs with +8, -8:

Sometimes, you will find written music where there is a treble clef (or some other clef) with a small 8. The meaning is that every note is to be played an octave higher than shown. Suppose you notate the abc note A using a treble clef. This appears as a note between the second and third lines from the bottom of the stave. Then with a treble+8 clef (which looks exactly the same except that it has a small 8), a note at the same position on the stave lines is now played as abc note a (which is normally put on a line one line up from the top line of the stave). Similarly, the treble-8 clef indicates that every note is to be played an octave lower than shown, so note A would be played as A, .

The abc standard versions 2.1 and 2.2 support this idea, but the way the abc notation is interpreted changes when you have clef=treble+8. With clef=treble+8, every stave position is interpreted as being an octave higher than if you had clef=treble e.g. the note that sounds as a does in normal abc is written as A in abc with clef=treble+8. The overall effect of this is that when you change a passage from clef=treble to clef=treble+8, without editing any of the notes, every note appears at exactly the same place on the stave lines as it did before, but it is played an octave higher.

The benefit of this change in interpretation is that you can notate very high or very low passages in abc without having to use lots of ' or , characters.

The octave specifier is a convenience to make entering music easier, developed before the +8/-8 clef modifier and still supported. However, to be compatible with other abc programs, it is recommended that you use the clef modifier. The syntax

I:octave=<offset in octaves>

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 are by classical convention considered to 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 so far there is very little abc notated on the web which exploits this feature.

duration

The duration 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 is 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.

Decorators
symbol effect example
dot staccato .e
M legato Me
H fermata He
T trill Te
R roll 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]. 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
symbol meaning
| ordinary barline
|| double barline
:| repeat last section
|: repeat next section
:: short for :| then |:
|1 or |[1 or | [1 first repeat ending
:|2 or :|[2 or :| [2 second repeat ending
[1,3 first and third ending
:|[2,4 second and fourth ending
|] and [| variants of ||

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. For 4/4 time this is applied to the 1/8 notes. For 2/4 time this is applied to the 1/16 notes.

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

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

notation played as
a<b (a/2b3/2) a2/3b4/3
a>>b a7/4b/4
a<<b a/4b7/4
a>>>b a15/8b/8
a<<<b 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 :

"Xm", "X7", "Xm7", "Xmaj7" "XM7" "X6", "Xm6", 
"Xaug", "X+", "Xaug7", "Xdim", "Xdim7", "X9", 
"Xm9", "Xmaj9", "XM9",  "X11", "Xdim9", "Xsus", 
"Xsus9", "X7sus4", "X7sus9", "X5"

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:

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.

Other Decorators

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 below for more details.

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 details.

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

!ped! and !ped-end! press and release the sustain pedal on the piano. The notes following !ped! and preceding !ped-end! are held. This effect applies to all instruments besides the piano.

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:

field effect
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 contain more than one set of lyrics in separate voices; an example is shown at the end of this section. By default the lyrics are embedded in the same MIDI track as the notes. If the runtime parameter -STFW is included, then the lyrics will be placed in separate and adjoining MIDI tracks. 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 :

symbol meaning
(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

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. Here are some examples taken from here.

string interpretation
w: syll-a-ble is aligned with three notes
w: syll-a--ble is aligned with four notes
w: syll-a -ble (equivalent to the previous line)
w: time__ is aligned with three notes
w: of~the~day is treated as one syllable (i.e. aligned with one note) but appears as three separate words

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.

Multivoiced lyrics example:

X:1
T:Multivoiced lyrics
M:2/4
L:1/16
K:C
V:1
C4 C4 | E4 G4 | c8 |]
w: 1 2 3 4 5
V:2
C4 E4 | C4 B,4 | C8  |]
w: 11 12 13 14 15

BarFly stress models

If you include the run time parameter -BF in execution string, abc2midi will attempt to apply the BarFly stress model on the tune if it recognizes the rhythm designator (eg. R: jig) and if the time signature also matches the associated meter. There are two different implementations of the stress model which have different effects. (See %%MIDI ptstress below for more details.) You can specify the implementation to use by following the -BF flag with either the numeral 1 or 2. If you do not specify a model, the program will use model 2. More details can be found here.

abc2midi-specific commands

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 0-127) 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 :

specifier equivalent
!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

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).

Another recent extension to gchords is the presence of gchords in separate voices. Here is an example:

X:1
T: gchord multivoice extension
M: 4/4
L: 1/4
K: G
V: 1
%%MIDI gchord ghih
"G" z4| z4|\
%%MIDI gchordoff
z4|
V:2
%%MIDI chordprog 12
%%MIDI gchord GHIHG
z4|"D" z4|z4|
%%MIDI chordprog n

Sets the MIDI instrument for the chord notes to be n. If the command includes the string octave=n where n is a number between -2 and +2, then the chord notes will be shifted n octaves from its usual position, eg. (%%MIDI chordprog 32 octave=1). Any other descriptors will be ignored, eg (%%MIDI chordprog 0 Acoustic Piano).

%%MIDI bassprog n

Sets the MIDI instrument for the bass notes to be n. If the command includes the string octave=n where n is a number between -2 and +2, then the bass note will be shifted n octaves from its usual position. eg. (%%MIDI bassprog 32 octave=-1).

%%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 can be found here.

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

%%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 drumbars 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 gchordbars n

This command spreads the gchord string over n consecutive bars of equal length. The gchord string should be evenly divisible by n or else the gchords will not work properly. A sample abc file is found in CHANGES March 17 2009.

%%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 weird, especially for large pitch intervals.

%%MIDI noportamento [bass/chord]

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

%%MIDI pitchbend [bass/chord] highbyte lowbyte

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 MIDI Controls

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 Controls
%%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.

Another recent extension is the allowance of drum patterns in separate voices. Here is an example:

X:1
T: drum multivoice extension
M: 4/4
L: 1/4
K: G
V:1
%%MIDI drum dddd 45 45 45 45 70 50 60 50
%%MIDI drumon
z4|z4|\
%%MIDI drumoff
z4|
V:2
%%MIDI drum ddddd 54 54 54 54 54 70 50 50 60 50 
z4|\
%%MIDI drumon
z4|z4|
%%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 here. 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 tuningsystem comma53

quantizes the pitches of the notes using the comma53 system where an octave is divided into 53 equally spaced tones.

%%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 propagate 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 in the execution string.

%%MIDI ptstress filename

This command loads file filename into abc2midi which contains the Phil Taylor stress parameters and puts abc2midi in the mode where it applies these stress parameters on every note. This model runs in opposition to the standard beat model, so the MIDI beat, beatstring, beatmod commands become ineffectual. This also means that the dynamic indications !f! !pp! etc. do not work any more.

There are two different implementations of the stress model.

The model divides a bar into equal segments. For each segment, a loudness or MIDI velocity is specified and a duration multiplier is specified. If a note falls into a specific segment, it assumes the velocity of that segment and its duration is modified accordingly. If the note overlaps more than one segment, then the note assumes the average of those segment values.

The input file specifies the number of segments and the loudness and duration multipliers for each segment. The file has the following format:

8
110 1.4
90 0.6
110 1.4
90 0.6
110 1.4
90 0.6
110 1.4
90 0.6

where the first value is the number of segments and each line specifies the velocity and duration multiplier of the specific segment. The velocity is limited to 127 and the duration is a decimal number. The note durations is modified by varying the gap between notes, so it is not possible to extend a note. This preserves the regular tempo of the music. The program scales, the note duration indications by dividing it by the maximum value which here is 1.4.

%%MIDI stressmodel n

where n is either 1 or 2, selects the stress model implementation.

%%MIDI expand m/n

This command,causes all the following notes be lengthened by the amount factor m/n so that they overlap the next note. Thus the next note is started at the proper time, but the previous note ends after the beggining of the note. This overlap causes a nice effect for particular MIDI instruments such as choir voices. The %%MIDI expand function behaves in the opposite manner as the %%MIDI trim function.

%%MIDI snt k pitch

Since many MIDI devices do not support this function, use of this command is not recommended. The command changes the tuning of a single note using the "universal system exclusive messages". k is the MIDI pitch being retuned (a number between 0 to 127) and pitch is a floating point number representing the pitch's new value in MIDI pitch units.

%%MIDI bendvelocity n1 n2

This command defines how to bend the a particular note following the !bend! decoration. The pitch of the note shifts up or down as the note is playing. n1 is the velocity of the pitch change and n2 is the acceleration (how fast the velocity changes). The bend is accomplished by modifying the MIDI pitchwheel where the 8192 is the neutral. Minimum and maximum values are 0 and 16383 correspond to two semitones shifts in either directions. The velocity and acceleration may be positive or negative.

%%MIDI bendstring n1 n2 n3 n4 etc

This command is a more general way for defining how a note is bent. It can also apply with !shape! decoration discussed later. The note is split into n equal segments corresponding to each of the n1, n2, etc values. The n1, n2, … values are the increments (or decrements if they are negative) which are added to the pitchwheel value. Thus %%MIDI bendstring 1000 1000 -500 -500 will split a note into 4 parts and the pitchwheel values in each part will be 9192, 10192, 9692, and 9192.

%%MIDI controlstring m n1 n2 n3 …

This command defines how the m MIDI controller changes for the note following the !shape! decoration. The note is divided into n segments where n is the number of values following the m or controller number. n1, n2, n3, … are the values for controller m in each segment. This allows you to shape the sound of the note. For example, by changing the modwheel or the expression. All the values m, n1, n2 are numbers between 0 and 127.

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 of 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.

Credits

This reference written 1995-1998 by James Allwright

Updates

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