abcmatch (1)

abcmatch abc file [-c] [-v] [-r] [-con] [-fixed nn] [-qnt] [-lev] [-a] [-ign] [-br %d] [-tp abc reference file] [-ver] [-pitch_hist] [-wpitch_hist] [-length_hist] [-interval_hist] [-pitch_table] [-interval_table] reference number

abcmatch is used to search for specific sequences of notes in an abc file composed of many tunes. 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

-v and -c

mainly used for debugging when the program does not do what was expected.

-ver

prints version number and then exits

--norhythm

Causes the matching algorithm to ignore the length of notes in a bar, thus E3/2F/D GA2 would match EFD G2A. The option ignores -r parameter since it is now irrelevant.

-pitch_table

Used to produce a interval weighted pitch histogram for each tune in the file. If this is saved in an external file, that file could be used as a database for finding tunes with similar pitch probability density functions (pdf).

-r

Controls how the matching criterion handles small rhythm variations in the melody. The -r option must be followed by a number which specifies the temporal resolution for the match. When the number is zero, this indicates that a perfect match should be performed, meaning that the lengths of each note in the bar must match exactly in order to be reported. For larger values a looser match will be performed as described below. Note lengths are converted into temporal units where a quarter note normally is assigned a value of 24. Therefore an eight note has a value of 12, a sixteenth has a value of 6, a half note has a value of 48 and etc. If you specify a temporal resolution of 12, then the pitch values of the notes only need to match at time units which are multiples of an eighth note.

-fixed n

Causes the program to disregard bar lines when does the matching. It allows matching of notes between tunes having different time signatures. n is a number which specifies the exact number of notes to match. For example if n is 4, the program could match |C E G E| .. with |C E|G E| Note the matcher still starts at a beginning of a given bar for both the tune and template.

-con

Specifies contour matching. In this case, the program uses the key signature only to indicate accidentals. The pitch contour is computed from the pitch difference or interval between adjacent notes.

-qnt

Uses the contour matching algorithm but also quantizes the intervals using the following table:

unison and semitone 0 minor 2nd to major 2nd 1 minor 3rd to major 3rd 2 any larger interval 3

Negative numbers are descending intervals.

-tp file name, reference number

Substitute any tune for the template match.abc. When using this feature, the entire tune is used as a template. Abcmatch does not match the template with itself, and only bars which match bars in other tunes are reported.

-br threshold

Runs the program in a brief mode designed to identify groups of tunes sharing common bars. In this mode, the program counts the numbers of bars in the test tune which are also present in match.abc. If the number of common bars is larger or equal to the threshold then the program reports the tune and the number of common bars. The program scans all the tunes in the abc file and returns a list of all the tunes which have more than a specific number of bars in common with the template, match.abc. In actual use, the program is run repeatedly by a script. For each tune in a abc file, it creates a template file called match.abc and then executes abcmatch. The outputs are displayed on the screen in a form easy to interpret. The user has no control of the matching criterion. The rhythm must match exactly and the notes are transposed to suit the key signature. In other words the -r parameter is independent of what is specified in the parameter list.

-pitch_hist or -length_hist

Runs the program in another mode. It produces a histogram of the distribution of the notes in the abc file. The pitch is indicated in midi units. Thus middle C is 60 and the pitches go up in semitone units. Following the pitch is a count of the number of times that note occurred.

-pitch_table or -interval_table

Used to create a database for a collection of tunes in a file for future analysis.

abc2abc(1), abc2midi(1), mftext(1) ,midi2abc(1) ,midicopy(1) ,yaps(1)

This manual page was written by Ross Gammon based on abcmatch.txt by Seymour Shlien.

This man page describes abcmatch version 1.35 from January 15 2006.