Using Spirent Wireshark 1.6.9 or higher, capture Spirent TestCenter signed traffic stream using the capture (Live capture, or post view capture). While in Spirent Wireshark, File>Export 'all' packets to a .PCAP file.
Now, issue the following command (Assuming Spirent Wireshark is in your path):
tshark -r "my_spirent_pcap.pcap" -E quote=d -E separator=, -E header=y -T fields -e frame.time -e eth.dst -e eth.src -e ip.dst -e ip.src -e stcsig.seqbyte -e stcsig.streamtype -e stcsig.streamid -e stcsig.csp -e stcsig.streamindex -e stcsig.seqnum -e stcsig.timestamp -e stcsig.prbseq -e stcsig.tslr > myresults.csv
The output file will be an ASCII .CSV file that you can load into Excel or any other tool for analysis or graphing.