Cron Job to convert Videos to MP4 and WebM using ffmpeg library. It uses file locking to prevent duplicate cron jobs being running simultaneously

ffmpeg-conversions.php

<?php
$f = fopen('lock', 'w') or die ('Cannot create lock file');
if (flock($f, LOCK_EX | LOCK_NB)) {
    ini_set('max_execution_time', 0);

    /**
    Database Configurations

    **/

    $servername = "localhost";
    $username   = "xyz";
    $password   = "password";
    $dbname     = "db";
    $tbl_name   = "profile_video"; // Table from which videos can be accessed

    /**
    Variables

    **/
    $path_ffmpeg    = '/usr/local/bin/ffmpeg';
    $path_ffprobe   = '/usr/local/bin/ffprobe';
    $path_to_videos = '/path/to/web/videos/';

 
    // Create connection
    $conn = new mysqli($servername, $username, $password, $dbname);
    // Check connection
    if ($conn->connect_error) {
        die("Connection failed: " . $conn->connect_error);
    } 
    echo "Connected successfully";


    $sql = "SELECT * FROM $tbl_name where converted = 0";
    $result = $conn->query($sql);

    if ($result->num_rows > 0) {
        // output data of each row
        while($row = $result->fetch_assoc()) {
            $videoname = $row["video_name"];
            $video_without_extension = substr($videoname, 0, strrpos($videoname, "."));

            $input_file_path = $path_to_videos.$videoname;
            $output_mp4_name  = $path_to_videos."converted-".$video_without_extension."-mp4.mp4";
            $output_webm_name = $path_to_videos."converted-".$video_without_extension."-webm.webm";
            $frame            = $path_to_videos."converted-".$video_without_extension.".jpg";


            echo "Converting: ". $input_file_path;

            exec($path_ffmpeg.' -i '.$input_file_path.'  -s hd480 -vcodec libvpx -g 120 -lag-in-frames 16 -deadline good -cpu-used 0 -vprofile 0 -qmax 63 -qmin 0 -b:v 768k -acodec libvorbis -ab 112k -ar 44100 -f webm '.$output_webm_name);
            exec($path_ffmpeg.' -y -i '. $input_file_path. ' -s hd480 -c:v libx264 -c:a copy '.$output_mp4_name);
           
            //execute ffmpeg and create thumb
            exec($path_ffmpeg.'  -i '.$input_file_path.' -f mjpeg -vframes 1 -s 150x150 -an '.$frame.'');

            //check if file exists (i.e it has been converted)
            //then update in database
            if (file_exists($output_webm_name) && file_exists($output_mp4_name)) {
                $sqli = "update $tbl_name set converted = 1 where id = ".$row['id'];

                if ($conn->query($sqli) === TRUE) {
                    echo "Record updated successfully";
                } else {
                    echo "Error updating record: " . $conn->error;
                }
                
            }


        }
    } else {
        echo "0 results";
    }

    $conn->close();
}

?>