if ( ! function_exists( 'issue_5253066_remove_from_post_format' ) ) :
function issue_5253066_remove_from_post_format($content) {
	global $post;

	$content = preg_replace('/\[audio mp3=(\'|")(.+?)(\'|")\]\[\/audio\]/', '$2', $content);

	return $content;
}
add_filter( 'the_content', 'issue_5253066_remove_from_post_format', 7 );
endif;