Duration Reference

This document describes how note/rest durations are represented in MuseScore, including tick values and the setDuration() method.

Source File

docs/ticklength.md

Duration Basics

Durations in MuseScore are expressed as fractions of a whole note. The Cursor's setDuration(z, n) method takes a fraction z/n.

Common Duration Values

Standard Note Values

Dotted Note Values

A dot adds half the value. The formula is: duration * 3/2

Double-Dotted Note Values

Double dot adds 3/4 of the original value. Formula: duration * 7/4

Tick Values

Internally, MuseScore uses "ticks" to measure time. The number of ticks per quarter note is defined by the division property (typically 480).

Tick Length Table

Working with Duration

Setting Duration via Cursor

var cursor = curScore.newCursor();
cursor.rewind(Cursor.SCORE_START);

// Standard durations
cursor.setDuration(1, 4);    // Quarter note
cursor.addNote(60);

cursor.setDuration(1, 8);    // Eighth note
cursor.addNote(62);

// Dotted duration
cursor.setDuration(3, 8);    // Dotted quarter
cursor.addNote(64);

Duration via Pad Actions

You can also set duration using pad actions:

cmd("pad-note-4");    // Set quarter note duration
cmd("note-c");        // Enter C with quarter duration

cmd("pad-note-8");    // Set eighth note duration
cmd("pad-dot");       // Add dot (now dotted eighth)
cmd("note-d");        // Enter D with dotted eighth duration

Reading Duration from Elements

if (cursor.element && cursor.element.type == Element.CHORD) {
    var chord = cursor.element;
    var duration = chord.duration;    // Fraction object
    console.log("Duration: " + duration.numerator + "/" + duration.denominator);
}

Tuplets

Tuplets allow non-standard divisions of time.

Common Tuplet Ratios

Creating Tuplets via Action

// Enter triplet mode and add notes
cmd("triplet");       // Start triplet
cmd("note-c");        // First triplet note
cmd("note-d");        // Second triplet note
cmd("note-e");        // Third triplet note (completes triplet)

Creating Tuplets via Cursor

cursor.setDuration(1, 4);  // Quarter note base duration
var ratio = fraction(3, 2);          // 3:2 ratio (triplet)
var duration = fraction(1, 4);       // Total duration of tuplet

curScore.startCmd("Add Triplet");
cursor.addTuplet(ratio, duration);

// Now add the notes inside the tuplet
cursor.setDuration(1, 8);  // Eighth notes inside triplet
cursor.addNote(60);
cursor.addNote(62);
cursor.addNote(64);
curScore.endCmd();

Duration Types (DurationType.*)

Time Signatures

Time signatures affect how durations are grouped and beamed.

Common Time Signatures

Working with Time Signatures

// Get time signature at cursor
var measure = cursor.measure;
var timeSig = measure.timesig;
console.log("Time signature: " + timeSig.numerator + "/" + timeSig.denominator);

Practical Examples

Creating a Rhythm Pattern

function addRhythm(cursor) {
    curScore.startCmd("Add Rhythm");

    // Quarter note
    cursor.setDuration(1, 4);
    cursor.addNote(60);

    // Two eighth notes
    cursor.setDuration(1, 8);
    cursor.addNote(62);
    cursor.addNote(64);

    // Dotted quarter + eighth
    cursor.setDuration(3, 8);
    cursor.addNote(65);
    cursor.setDuration(1, 8);
    cursor.addNote(67);

    curScore.endCmd();
}

Creating a Compound Meter Pattern

function add6_8Pattern(cursor) {
    curScore.startCmd("Add 6/8 Pattern");

    cursor.setDuration(1, 8);

    // First beat group (3 eighths)
    cursor.addNote(60);
    cursor.addNote(62);
    cursor.addNote(64);

    // Second beat group (3 eighths)
    cursor.addNote(65);
    cursor.addNote(67);
    cursor.addNote(69);

    curScore.endCmd();
}

Filling a Measure with Rests

function fillWithRests(cursor, timeSigNumerator, timeSigDenominator) {
    curScore.startCmd("Fill with Rests");

    // Calculate number of rest units needed
    cursor.setDuration(1, timeSigDenominator);

    for (var i = 0; i < timeSigNumerator; i++) {
        cursor.addRest();
    }

    curScore.endCmd();
}

// Fill a 4/4 measure
fillWithRests(cursor, 4, 4);

Helper Functions

// Convert BPM and duration to seconds
function durationToSeconds(durationFraction, bpm) {
    var beatsPerSecond = bpm / 60;
    var quarterNotesPerSecond = beatsPerSecond;  // Assuming quarter = beat
    var wholeNotesPerSecond = quarterNotesPerSecond / 4;
    var duration = durationFraction.numerator / durationFraction.denominator;
    return duration / wholeNotesPerSecond;
}

// Get note duration as string description
function durationToString(z, n) {
    var durations = {
        '2/1': 'breve',
        '1/1': 'whole',
        '1/2': 'half',
        '1/4': 'quarter',
        '1/8': 'eighth',
        '1/16': '16th',
        '1/32': '32nd',
        '1/64': '64th',
        '3/2': 'dotted whole',
        '3/4': 'dotted half',
        '3/8': 'dotted quarter',
        '3/16': 'dotted eighth',
        '3/32': 'dotted 16th'
    };
    var key = z + '/' + n;
    return durations[key] || (z + '/' + n);
}