What would happen if you sent your own UDP packets on the same port? Could you manipulate the elevator music? Or would it turn into noise as the elevators receive packets from both sources?
Not my space, but googling around a bit on how ADTS works, it can include everything needed to send a "playable" bit of MP3 data in a single frame.
So it seems like if you started sending multicast packets, the sound would be interleaved with the other stream. If you used a lower bitrate (they are using 192kbps) you could have a bigger piece of the playing time slice, since each of your packets would be a longer running snippet. Similarly, going mono vs stereo would extend that more.
Given that it's a hotel, lots of the devices probably have default admin passwords though, so shutting off the other stream is probably not hard :)
