sub process_rtp_packets {
    my ($user_data, $header, $packet) = @_;

    for my $key ( keys %header ) {
        my $value = $header{$key};
        print "$key => $value\n";
    }
    my $eth_obj = NetPacket::Ethernet->decode($packet);
    my $ether_data = NetPacket::Ethernet::strip($packet);
    my $ip_obj = NetPacket::IP->decode($ether_data);
    my $ip_data = NetPacket::IP::strip($ether_data);
    my $udp_obj = NetPacket::UDP->decode($ip_data);
    my $RTP_data = $udp_obj->{data};
    my( $bits, $type, $seq, $time )= unpack "C C n N", $RTP_data;
        print "$bits\n";
        print "$type\n";
        print "$seq\n";
        print "$time\n";
}