Fatal error: Call to undefined function media_filter
Prior to newer version of Media, media_wysiwyg_filter should be used instead which will perform media markup filter. This can be found in modules/media_wysiwyg/includes/media_wysiwyg.filter.inc.

The code is:

/**
 * Filter callback for media markup filter.
 */
function media_wysiwyg_filter($text) {
  $text = preg_replace_callback(MEDIA_WYSIWYG_TOKEN_REGEX, 'media_wysiwyg_token_to_markup', $text);
  return $text;
}