rtspextr accepts an RTSP stream from stdin and analyses it extracting the RTSP and payload (interleaved data) packets. The extracted packets can be re-transmitted or dumped in various ways.

The following options are handled:

• -h, --help: print this help screen;
• -q, --quiet: output nothing;
• -u <IP>:<PORT>, --udp=<IP>:<PORT>: send data via UDP to IP:(PORT + CHN);
• -U <DIR>, --unix=<DIR>: send data to the local socket 'rtspextr.CHN' in the direcotry DIR;
• -P <DIR>, --pcap=<DIR>: write down libpcap dumps CHN.pcap' to the directory DIR (the option is available only when the program is built with libpcap support);
• -C <MAXCHN>, --maxchn=<MAXCHN>: limit the possible channel number to MAXCHN;
• -L <MAXLEN>, --maxlen=<MAXLEN>: limit the possible packet length to MAXLEN;
• -R <COUNT>, --reportevery=<COUNT>: print report every COUNT packets.

The CHN parameter above is the RTSP channel number (0--255). It is used as suffix for socket and dump filenames. The special value "rtsp" is used as suffix to send/dump the RTSP-data itself. When retransmitting packages via UDP, the RTSP-data is always sent with PORT + 256 as the destination port number.

In order to improve the RTSP stream identification by filtering out the garbage trafic the valid channel value range is narrowed to 0--16 by default. This restriction can be overridden with the -C option. The other disambiguation parameter is the RTSP channel payload maximal length which is set to 2048 bytes by default and can be overridden with the -L option.

# Retransmit the RTSP payload from the 'rtsp.test.stream' file
# via UDP to the destination 192.168.0.55:1000:

rtspextr -u 192.168.0.55:1000 <rtsp.test.stream

The channel number 0 data is sent to the port 1000, channel 1 --- to the port 1001 and so on. The RTSP data is sent to the port 1257.

# Dump the RTSP stream from the 'rtsp.test.stream' file into
# the set of *.pcap files in the directory 'rtsp.test.out':

mkdir -p rtsp.test.out
rtspextr -P rtsp.test.out <rtsp.test.stream

The channel number 0 data is written to the file rtsp.test.out/0.pcap, channel 1 to the rtsp.test.out/1.pcap and so on. The RTSP data is written to the rtsp.test.out/rtsp.pcap file.