You can hide unneeded frames using a Display Filter.
Note: A complicated display filter may have a bad impact on capturing performance.
Capturing Filter is useful for discarding unneeded frames and reducing CPU usage.
This function is provided not by Dripcap but by libpcap and it accepts only BPF (Berkeley Packet Filter) Syntax.
Please see http://biot.com/capstats/bpf.html for the details.
Note: Unlike Display Filter, you can not retrieve discarded frames after the filtering.