merges duplicate lines in a subtitle file that are meant to be one with proper timings

submerge.php

<?php
    define('SRT_STATE_SUBNUMBER', 0);
    define('SRT_STATE_TIME',      1);
    define('SRT_STATE_TEXT',      2);
    define('SRT_STATE_BLANK',     3);
    
    function parseSrt($lines) {
        
        $subs    = array();
        $state   = SRT_STATE_SUBNUMBER;
        $subNum  = 0;
        $subText = '';
        $subTime = '';
        
        foreach($lines as $line) {
            switch($state) {
                case SRT_STATE_SUBNUMBER:
                    $subNum = trim($line);
                    $state  = SRT_STATE_TIME;
                    break;

                case SRT_STATE_TIME:
                    $subTime = trim($line);
                    $state   = SRT_STATE_TEXT;
                    break;

                case SRT_STATE_TEXT:
                    if (trim($line) == '') {
                        $sub = new stdClass;
                        $sub->number = $subNum;
                        list($sub->startTime, $sub->stopTime) = explode(' --> ', $subTime);
                        $sub->text   = $subText;
                        $subText     = '';
                        $state       = SRT_STATE_SUBNUMBER;

                        $subs[]      = $sub;
                    } else {
                        $subText .= $line;
                    }
                    break;
            }
        }
        
        return $subs;
    }
    
    $input = file($argv[1]);
    $input_srt = parseSrt($input);
    $input_lines = count($input_srt);
    
    $sametext = 0;
    $offset = 0;
    
    for($i = 0; $i < $input_lines; $i++) {
        if($i+1 < $input_lines) {
            if($input_srt[$i]->text == $input_srt[$i+1]->text) {
                $sametext = 1;
                $offset++;
            } else {
                $sametext = 0;
            }
        }
        
        if($sametext === 0) {
            echo $input_srt[$i]->number."\r\n";
            echo $input_srt[$i-$offset]->startTime." --> ".$input_srt[$i]->stopTime."\r\n";
            echo $input_srt[$i]->text."\r\n";
            $offset = 0;
        }
    }
?>