rtp profile (payload type)
1. sdp add sdp_media_proto/sdp_media_formats
2. sdp add sdp_media_attribute_list
3. add sdp fmtp attribute parser(h264/mpeg4)
4. add sdp rtpmap attribute parser
rtsp client announce/describe/play/pause/setup/teardown
rtsp header session parser
1. rtsp server
2. rtsp udp/tcp transport