TransportAudioCall::getDuration

public function getDuration(Message\Adapter $message = null)
{
	$length = 0;
	$fileJson = $message->getConfiguration()->get('AUDIO_FILE');
	if ($fileJson)
	{
		$audio = (new Audio())
			->withJsonString($fileJson)
			->withMessageCode($message->getCode());

		$length = $audio->getDuration();
	}
	$length = $length ?: 20;
	$magic = 5;
	$limit = $this->getCountLimiter()->getLimit();

	return round(($length + $magic) / $limit);
}