pcap to text/csv conversion takes long time

I have captured traffic in pcap file and trying to convert the pcap file into txt/csv. I am using tshark -V -r infile.pcap > outputfile.txt/csv. I am observing that, the time taken to convert 100MB of pcap file takes more than average 10min on Xeon Dual core 2GB RAM system. This is the performance bottleneck for me as I want the time taken to convert the file at least linear with time taken to capture 100 MB of data on 100 MB NIC.