code: private void checkMessageForContent(final SipPacket msg) {
          if (!msg.hasContent()) {
              return;
          }
  
          try {
              final Object content = msg.getContent();
              if (content instanceof SDP) {
                  for (final RTPInfo rtpInfo : ((SDP) content).getRTPInfo()) {
                      final String address = rtpInfo.getAddress();
                      final int port = rtpInfo.getMediaPort();
                      // System.out.println("Address: " + address + " port : " + port);
                  }
              }
          } catch (final SipPacketParseException e) {
              // System.err.println("Ok so the total length is: " + msg.getTotalLength());
              logger.warn("Unable to parse the content of the sip message", e);
              // System.exit(1);
          }
  
      }
docs: Check whether a {@link SipPacket} has a message body and if it is SDP
  then figure out what ports etc we can expect to see RTP on (if that is
  what is being advertised) and tell the {@link FramerManager} about this.
  
  @param msg