mime type recognition

<html>
<head><title>http://stackoverflow.com/questions/16842129/how-to-upload-mp3-mp4-3gp-files-using-php</title></head>
<body>
<?php

function get_mime($file) {
  if (function_exists("finfo_file")) {
    $finfo = finfo_open(FILEINFO_MIME_TYPE); // return mime type ala mimetype extension
    $mime = finfo_file($finfo, $file);
    finfo_close($finfo);
    return $mime;
  } else if (function_exists("mime_content_type")) {
    return mime_content_type($file);
  } else if (!stristr(ini_get("disable_functions"), "shell_exec")) {
    // http://stackoverflow.com/a/134930/1593459
    $file = escapeshellarg($file);
    $mime = shell_exec("file -bi " . $file);
    return $mime;
  } else {
    return false;
  }
}

var_export($_FILES);
if (!empty($_FILES)) {
  var_dump(get_mime($_FILES['file1']['tmp_name']));
}

?>

<form name="files1" action="" method="post" enctype="multipart/form-data">
  <input type="file" name="file1" />
  <input type="submit" value="Send" />
</form>

</body>
</html>