One problem with the generic streaming command is it does not force a nice mapping between transport packet size and the IP transport packet size. One possible modification to your command line is to add the packet size onto the destination address:
ADD 1 STREAM udp://127.0.0.1:5000?pkt_size=1316 -format...
This sets 7 transport packets per ethernet packet.
There is an example streaming command in the link below that several users found worked for them.