Convert seconds to timestamp?

Question

I am creating a PHP script to generate a json from a caption file webvtt, take the beginning and the end that are in the format minuto:segundo.milisegundo or if the video is too big they come as hora:minuto:segundo.milisegundo for future JS comparisons in the future where the video is playing need to compare these values with the currentTime video which in turn delivers time in seconds segundos.milisegundos and to facilitate such a comparison I would like my PHP to already deliver the start and end time of each legend already in the same format as the currentTime of the video, how can I?

Here’s an example:

$start = "00:05.570";
$fim = "00:09.700";

In the above example it would be easy to distinguish that the currentTime would be 5.570 and 9.700 how do I convert PHP to this format?

Answer 1

Solution

A solution using regular expressions would be, making only the second value mandatory:

function convert($value)
{
    if (preg_match("/(((?P<hours>\d+)\:)?(?P<minutes>\d{1,2})\:)?(?P<seconds>\d{1,2})(\.(?P<milis>\d+))?/", $value, $matches))
    {
        $hours   = intval($matches["hours"]);
        $minutes = intval($matches["minutes"]);
        $seconds = intval($matches["seconds"]);
        $milis   = isset($matches["milis"]) ? intval($matches["milis"]) : 0;

        return sprintf("%d.%d", $hours * 3600 + $minutes * 60 + $seconds, $milis);
    }

    return false;
}

// Entrada: horas:minutos:segundos.milis
echo convert("123:12:42.9"), PHP_EOL;   // 443562.9

// Entrada: horas:minutos:segundos.milis
echo convert("01:20:03.7345"), PHP_EOL; // 4803.7345

// Entrada: horas:minutos:segundos.milis
echo convert("0:01:56.23"), PHP_EOL;    // 116.23

// Entrada: minutos:segundos.milis
echo convert("00:05.570"), PHP_EOL;     // 5.570

// Entrada: minutos:segundos.milis
echo convert("00:09.700"), PHP_EOL;     // 9.700

// Entrada: minutos:segundos
echo convert("00:05"), PHP_EOL;         // 5.0

// Entrada: segundos.milis
echo convert("4.55"), PHP_EOL;          // 4.55

// Entrada: segundos
echo convert("12"), PHP_EOL;            // 12.0

See working on Ideone.

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Explanation

The solution was entirely based on PHP’s native function preg_match:

int preg_match ( string $pattern , string $subject [, array &$matches [, int $flags = 0 [, int $offset = 0 ]]] )

The first parameter, $pattern, is the regular expression we will analyze. The second, $subject, is the string on which we will apply the regular expression and the third parameter, $matches, will be a array with the values of string that match the pattern defined in the regular expression.

The regular expression used is divided into four parts:

/(((?P<hours>\d+)\:)?(?P<minutes>\d{1,2})\:)?(?P<seconds>\d{1,2})(\.(?P<milis>\d+))?/
  +-----------------+-----------------------+-------------------+------------------+
      (horas)               (minutos)             (segundos)          (milis)

Regular expression: hours

The regular expression for hours, ((?P<hours>\d+)\:)?, may be reduced to (\d+\:)?, which means one or more digits (\d+) followed by a character : (\:) optional (?). The part ?P<hours> serves only to name the group; i.e., if there is a value that matches this pattern, create in $matches the index hour with the value matched. For example, if the input is 01:20:03.7345, there will be $matches["hours"] equal to 01. If time is not set, $matches["hours"] will be false (because we defined that it was optional in regular expression).

Regular expression: minutes

Vide hours (exactly the same logic, just changing the group name to minutes, ((?P<minutes>\d{1,2})\:)?). The quantifier of + for {1,2}, because minutes will have 1 or 2 digits: 1 if it is less than 10 minutes (whereas 0 may not be added to the left) or 2 digits when 10 to 59 minutes.

Regular expression: seconds

It is basically the same expression used for minutes, differentiating only that it will be mandatory, so there will be no character ? in the end, (?P<seconds>\d{1,2}).

Regular expression: Milis

For the milliseconds, (\.(?P<milis>\d+))?, stays: if defined (?), must start with the character . (\.) followed by one or more digits (\d+), capturing this group under the name of milis. Note that the \. is not part of the nominated group as we only want the numerical value, otherwise, $matches["milis"] would be something like .570 instead of 570.

Answer 2

Personally I would prefer to work with the function DateTime native to PHP

You would have to set the date to 01/01/1970, the rest he would do the conversion...

echo timestamp('00:00:30.570')."<br/>"; //30.57
echo timestamp('00:10:30.570')."<br/>"; // 630.57
echo timestamp('12:10:30.570')."<br/>"; // 43830.57

function timestamp($horario){
    list($sec, $msec) = explode('.', $horario);
    $date = '01/01/1970 '.$sec;
    $dateTime = DateTime::createFromFormat('d/m/Y H:i:s', $date, new DateTimeZone('GMT'));
    $timestamp = $dateTime->getTimestamp();
    return $timestamp+($msec/1000);
}

Ai would be in charge of you define better how you would like the return, depends a lot on your need and how you intend to work from here / Forward