Calculate measure and beat durations in seconds

PhpTabs provides some useful methods to calculate durations.

Measure duration

To calculate duration in seconds, the formula is (Number of beats) * 60 / Tempo.

The following code prints duration for the first measure of the first track.

use PhpTabs\PhpTabs;

// Instanciate a tablature
$song = new PhpTabs('myTab.gp5');

// Take a measure
$measure = $song->getTrack(0)->getMeasure(0);

// Calculate duration in seconds
$duration = 60
    * $measure->getTimeSignature()->getNumerator()
    / $measure->getTempo()->getValue();

// Print duration
echo sprintf("Duration=%ss", $duration);

With a 4/4 time signature and a tempo of 120, this example will ouput:

Duration=2s

---

Beat duration

Calculating beat duration in seconds is quite more complex. It depends on:

• tempo
• time signature
• non dotted, dotted or double dotted beat
• division type

PhpTabs (>=0.6.0) provides a shortcut method to easily get this value.

The getTime() method is provided by the PhpTabs\Music\Voice model.

The following code prints duration for the first beat of the first measure of the first track.

use PhpTabs\PhpTabs;

// Instanciate a tablature
$song = new PhpTabs('myTab.gp5');

// Take a beat
$beat = $song->getTrack(0)->getMeasure(0)->getBeat(0);

// Get duration in seconds for the first voice
$duration = $beat->getVoice(0)->getTime();

// Print duration
echo sprintf("Duration=%ss", $duration);

With a 4/4 time signature, a tempo of 120 and for a quarter beat, this example will ouput:

Duration=0.5s

---

Song duration

In order to calculate the duration of the complete song, we will add up the durations of each measure.

For one measure, the duration is calculated with the formula: (Number of beats) * 60 / Tempo.

use PhpTabs\PhpTabs;

// Instanciate a tablature
$song = new PhpTabs('myTab.gp5');

$total = 0;

// Take all measures for the first track
$measures = $song->getTrack(0)->getMeasures();

// Add up durations for each measure
foreach ($measures as $measure) {

    // Calculate duration in seconds
    $total += 60
        * $measure->getTimeSignature()->getNumerator()
        / $measure->getTempo()->getValue();

}

// Print duration
echo sprintf("Duration=%ss\n", $total);

With a 4/4 time signature, a tempo of 120 and 10 measures, this example would ouput:

Duration=20s