Getting the Duration of a Video with PHP

I wanted to calculate the duration of a video in seconds as in integer variable. For this I needed software outside of PHP. So, I decided to use the open source video encoding library, avconv, running on Linux Mint / Ubuntu.

If you pass a video to avconv, it returns meta-data about the video, including its duration, e.g.

$avconv -i myvideo.mp4
avconv version 0.8.10-6:0.8.10-0ubuntu0.13.10.1, Copyright (c) 2000-2013 the Libav developers
built on Feb  6 2014 20:53:28 with gcc 4.8.1
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'myvideo.mp4':
Metadata:
major_brand     : mp42
minor_version   : 1
compatible_brands: mp42mp41
creation_time   : 2013-11-23 13:44:21
Duration: 00:00:03.76, start: 0.000000, bitrate: 393 kb/s

A search on the Ubuntu forums returned an easy way to parse the above output using Linux scripting1.

avconv -i myvideo.mp4 2>&1 | grep 'Duration' | awk '{print $2}' | sed s/,//

This will extract the timestamp after the text after “Duration”. The 2>&1 is important as avconv sends it’s output to standard error rather than standard output. I coded this in PHP as below.

$cmd = "avconv -i '$video' 2>&1 | grep 'Duration' | awk '{print $2}' | sed s/,//";
exec($cmd, $result, $error);
$duration = $result[0];

Once, I had the above data (e.g.  “00:00:03.76”) in a string, I needed to convert it to an integer value. Further research returned the following snippet of PHP code

list($hours,$mins,$secs) = explode(':',$duration);
$seconds = mktime($hours,$mins,$secs) - mktime(0,0,0);

The first mktime returned a timestamp relative to the current time, so we need to subtract the number of seconds from the current timestamp at midnight. This gives us the number of seconds in our video as an integer value.

 
References

Raguet Roman, 2012, accessed  21 April 2014, <http://www.askubuntu.com/questions/224237/how-to-check-how-long-a-video-mp4-is-using-the-shell>.
2012, Stack Overflow, accessed  21 April 2014,<http://www.stackoverflow.com/questions/4605117/how-to-convert-hhmmss-string-to-seconds-with-php>.

 

Splitting a file path in PHP

During the week, I was faced with the problem of dividing a given string containing a file path into the file name, extension and the path to the file’s directory. For example, “/home/myuser/myfile.ext”, has to be split into “/home/myuser/”, “myfile” and “ext”.

My first instinct was to use PHP’s explode(function to split the string on the forward slash. This would give me my file name and extension in the last element of the returned array and each of the directories of my path in the preceding elements. Of course, I would then have to build my directory path from these elements before returning the result, re-inserting the forward slash along the way.

This did not strike me as an elegant way to proceed. So on further reflection, I started my solution using basename(). This returns the file name and extension for a given file path. From here, I used explode to split the base file name into it’s file name and extension. Note that I did not store the “.” between the file name and extension as the specification did not require this.

Now, I needed the directory path to the file. Of course, my input string already had this information. I just had to remove the file name and extension from the end. So, I used substr() to get the sub string from the start of the source path less the length of the base file name (with it’s extension).

This struck me as being a more succinct resolution which is more intuitive to understand. I have included some sample code below.

class PathSplitter {

    function __construct() {
        $source = "/home/myuser/myfile.ext";
        echo "Source path: {$source}\n\n";

        $splitPath = $this->splitPath($source);

        echo "Split Path:\n";
        var_dump($splitPath);
    }

    private function splitPath($source) {

        // Get the file name and extension, i.e. the basename
        $baseName = basename($source);

        // Break down the basename into file name and extension
        $parts = explode(".", $baseName);

        $name = $parts[0];
        $extension = $parts[1];

        // The path is the full path name less the basename
        $path = substr($source, 0, -strlen($baseName));

        $splitPath = array(
            "path" => $path,
            "name" => $name,
            "extension" => $extension
        );
        return $splitPath;
    }

}