I am trying to stream a MP3 over the LAN using VLC Player(1.0.5.0), RTP multicast. On observation with wireshark in the receiving side,it interprets all the below fields: padding, extension, contributing source identifier count as 0, which means there are no additional byte after the first 12 bytes of fixed RTP header.
But I could see 4 bytes of zero included in the start of the payload, these 4 bytes of zero are not part of the MP3 data that I streamed(I just performed a hex comparison with the transmitted MP3 and with the payload of all the received packets, I also used the sequence number) and the rest of the received bytes (i.e from 5th byte)are intact with the transmitted MP3. This pattern is repeated in all the streamed packets.
Can people in this loop help me with thoughts to figure out what this 4 bytes of zero in each payload represents to? It would be highly appreciable.