MIDISTATS(1)

NAME
midistats - program to summarize the statistical properties of a midi file

SYNOPSIS
midistats infile

DESCRIPTION
midistats analyzes the contents of a midi file and outputs key information and various statistical measures. Each line of output starts with the name of the variable or variable array and the associated values. The output is interpreted by the user interface midiexplorer.tcl. Both programs are still being improved. Here is an explanation of some of the output.

ntrks indicates the number of tracks in the midi file.

ppqn the number of midi pulses per quarter note.

keysig the key signature, followed by a major/minor flag, the number of sharps (positive) or flats (negative) in the key, and the beat number where the key signature was found.

trk is followed by the track number for which the following information applies.

program is followed by the channel number and the General Midi Program number.

trkinfo is an array of 8 numbers which indicates the statistical properties of the track of interest. The following data is given: the channel number, the first program assigned to this channel, the number of notes for this channel counting any chords as one note, the total number of notes for this for this channel, the sum of the MIDI pitches for all the notes, the sum of the note durations in MIDI pulse units, the number of control parameter messages, the number of pressure messages. and the number of distinct rhythm patterns for each channel

After processing all the individual tracks, the following information applies to the entire midi file.

npulses is the length of the longest midi track in midi pulse units

tempocmds specifies the number of times the tempo is changed in this file.

pitchbends specifies the total number of pitchbends in this file.

progs is a list of all the midi programs addressed

progsact the amount of activity for each of the above midi programs. The activity is the sum of the note durations in midi pulse units.

progcolor: is a 17 dimensional vector where each component maps into a specific group of MIDI programs. Some of these groups are, keyboard instruments, brass instruments, wind instruments, and etc. More information can be found in the midiexplorer documentation.

drums is a list of all the percussion instruments (channel 9) that were used.

drumhits indicates the number of notes for each of the above percussion instruments.

pitches is a histogram for the 11 pitch classes (C, C#, D ...B) that occur in the midi file.

pitchact is a similar histogram but is weighted by the length of the notes.

quietTime is used to compute the track/channel spread in midiexplorer. It is computed by summing up all the midi pulses which occur in gaps greater than 8 beats.

totalrhythmpatterns is the total number of bar rhythm patterns for all channels except the percussion channel.

collisions. Midistats counts the bar rhythm patterns using a hashing function. Presently collisions are ignored so occasionally two distinct rhythm patterns are counted as one.

Advance Percussion Analysis Tools

A number of experimental tools for analyzing the percussion channel (track) were introduced into midistats and are accessible through the runtime arguments. When these tools are used in a script which runs through a collection of midi files, you can build a database of percussion descriptors. Some more details are given in the file drums.txt which comes with this documentation.

AUTHOR
Seymour Shlien <fy733@ncf.ca>