This will recursively list video files (currently filtered by a '.mp4' preg_match) links when put at the root of a url.

list-video-file-links-recursively.php

<?php
function readDirs($path){
  $dirHandle = opendir($path);
  while($item = readdir($dirHandle)) {
    $newPath = $path."/".$item;
    if(is_dir($newPath) && $item != '.' && $item != '..') {
       readDirs($newPath);
    }
    else{
      if(preg_match('/\.mp4/', $newPath) === 1){
        $relative_path = preg_replace('/' . preg_quote($_SERVER['DOCUMENT_ROOT'], '/') . '/', '', $newPath);
        echo '<p><a href="' . $relative_path . '">' . $newPath . '</a></p>';
      }
    }
  }
}

$path =  __DIR__;
$original_path = $path;

echo "$path<br>";

readDirs($path);