We playing DTMF digits on poly phone through our java based app and we capturing start time and end time of playing dtmf digits and also capturing trace for this dtmf . Once all this process completed, we have pcap file with dtmf events.This pcap file also have other packets of SIP signal. Now we want to filter pcap file for packets which are fall between captured start and end time in java app by passing these two time stamps to tshark command as display filter. So which timestamp i have to consider in packet rtp.timestamp or frame.time what is the time format? Please help me to achieve this problem.