It'll be sent in mp3 format... a complex digital format of codecs & compression that would be impossible for any alien race to decode, without full knowledge of the specific MP3 format... so basically it would be just noise to an alien race. To broadcast to alien races that know nothing of us or our specific digital schemes, one must transmit in analog, if they were to have any hope of hearing the transmission as it was intended, & possibly try to interpret it.