Provided by: abcmidi_20070318-3_amd64 
NAME
abcmatch - search sequences of notes in an ABC file
SYNOPSIS
abcmatch data-file [number] [-a] [-br d] [-c] [-con] [-ign] [-length_hist] [-pitch_hist]
[-qnt] [-r n] [-v] [-ver]
DESCRIPTION
abcmatch searches an ABC file containing (potentially) many tunes for specific sequences
of notes. For example, if you know a few bars of a tune, you can use this program to find
the tune having this sequence and perhaps identify the tune.
At a minimum, abcmatch requires two files. A template file called match.abc which contains
the bars that you are searching for and a large file consisting of a hundred or more ABC
tunes. The program automatically loads up the match.abc file and then scans every tune in
the large file.
Though the program can be run stand-alone, it is really meant to be run with a GUI such as
runabc.tcl (which is not yet part of Debian). Most of its output is rather cryptic.
THE MATCHING PROCESS
The template file must be a well-formed ABC file containing the basic X:, M:, L:, and K:
headers as well as the bars to be matched. (Normally, this file is created by runabc.tcl.)
It is important to finish each bar in the match file with a vertical line.
abcmatch uses the key signature to figure out the relative position of the notes in the
scale, and to determine all the assumed sharps and flats. Therefore the program can find
matching bars in a tune that has been transposed to another key, as long as the key
difference is not too large. Matches are output in a list format looking like
29 30 4
30 31 4
Each line indicates a particular match found by the program. The first number on each line
gives the relative position of the tune in the data-file, while the next number gives the
X: number of that tune. The last number is the bar number of the matching tune. Bar
numbers are counted sequentially from the start of the tune, and all V: and P: indications
are ignored. That is, the bar number returned by abcmatch may not match bar numbers
printed by one of the PostScript-producing ABC processors such as abcm2ps or abcmidi-yaps.
For the purposes of matching, abcmatch ignores all guitar chords, lyrics, note decorations
(e.g., staccato markings), grace notes, etc. In chords such as [G2c2], only the highest
note is considered. Any warnings or error messages from the ABC parser are suppressed
unless the -c option is given.
OPTIONS
-a Report any matching bars. By default, if the template file contains a sequence of
several bars, the program will try to find places in the data file where the whole
sequence matches. With this option, it returns all places in the data file where
any of the bars in the template file match.
-br d `Brief mode' is designed to identify groups of tunes sharing common bars. In this
mode, the program determines the number of all bars in each tune from the data file
which are also present in the template file. If the number of common bars is
greater than or equal to the value of the d parameter, the program reports the tune
and the number of common bars. Currently there is no user control of the matching
criterion; the rhythm must match exactly, and the notes are transposed to suit the
key signature.
-c Display error and warning messages from the ABC parser (which are suppressed by
default).
-con Do a pitch contour match. In this case, the program uses the key signature only to
indicate accidentals. The pitch contour is computed from the pitch difference
(interval) between adjacent notes. That is, C2 DE, c2 de, and G2 AB all have the
same pitch contour.
-ign Ignore simple bars.
-length_hist
This does no matching at all but returns a histogram of the distribution of note
lengths in the data file. The output looks like
length histogram
12 100
24 20
36 6
48 2
72 4
where a quarter note is 24 units, an eight note 12 units, a dotted half note 72
units etc.
-pitch_hist
This does no matching at all but returns a histogram of the distribution of pitches
in the data file. The output looks like
pitch histogram
64 2
66 9
67 11
where the first number on each line is a MIDI note number and the second is a count
of the number of times that note occurred.
-qnt Do a quantized pitch contour match. This works as described above for the -con
option, but will also quantize the intervals as follows: Unison and semitone
intervals are assigned value 0, major 2nds to major 3rds value 1, and a perfect 4th
or greater value 2. Negative numbers are used for descending intervals.
-r n Resolution for matching. If the n parameter is zero, a perfect match must be found,
meaning that the lengths of each note in a bar must match exactly in order to be
reported. The larger the value of n, the looser the match will be. Note lengths are
converted into temporal units where a quarter note is normally assigned a value of
24 (therefore an eighth note has a value of 12, a sixteenth a value of 6, a half
note a value of 48 etc.) If you specify a temporal resolution of 12, then the pitch
values of the notes only need to match at the time units that are multiples of an
eight note. This means that the program would match the two bars C2 D2 and C C D D,
as well as C2 D2 and C/D/C/D/D2. By selecting a suitable value for n, you can
search for matches only at the beginning of a measure or at the beginning of each
beat.
-v Run verbosely.
-ver Display the program's version number.
LIMITATIONS
The program has some limitations. For example, the data file must contain bar lines, and
tied notes cannot be longer than the equivalent of 8 quarter notes. A resolution (-r
option) that is too small may cause some buffers to be exceeded. When there are
differences of key signatures of more than 5 semitones, the program may transpose the
notes in the wrong direction. Also, tunes with more than one key signature or time
signature may not be processed correctly.
SEE ALSO
abc2midi(1), midi2abc(1), mftext(1)
AUTHOR
This manual page was written by Anselm Lingnau <lingnau@debian.org> for the GNU/Linux
system.
VERSION
This manual page describes abcmatch version 1.42 as of 21 December 2006.
24 August 2007 ABCMATCH(1)