sudo apt-get install ros-indigo-people-msgs
sudo apt-get install libpcap-dev
To play back pcap log
roslaunch velodyne_pointcloud VLP16_points.launch pcap:=<path/to/pcap> device_ip=<velodyne_ip>
(Velodynes configures so that one is on 192.168.1.10 and the other 192.168.1.11)