I recently upgraded to Ubuntu 18.04. Earlier, I had ROS Kinetic but after porting to ROS Melodic, sensor plugins for both Hokuyo and Kinect are not working. This is the whole error:

adi99@adi99:~$ rosrun gazebo_ros gazebo --verbose Gazebo multi-robot simulator, version 9.11.0 Copyright (C) 2012 Open Source Robotics Foundation. Released under the Apache 2 License. http://gazebosim.org

[ INFO] [1575736807.119173313]: Finished loading Gazebo ROS API Plugin. [ INFO] [1575736807.120136990]: waitForService: Service [/gazebo/setphysicsproperties] has not been advertised, waiting... [Msg] Waiting for master. [Msg] Connected to gazebo master @ http://127.0.0.1:11345 [Msg] Publicized address: 192.168.0.105 [ INFO] [1575736807.511719407, 0.024000000]: waitForService: Service [/gazebo/setphysicsproperties] is now available. [ INFO] [1575736807.537814805, 0.047000000]: Physics dynamic reconfigure ready. [Wrn] [msgs.cc:1852] Conversion of sensor type[depth] not supported. [Wrn] [msgs.cc:1852] Conversion of sensor type[depth] not supported. [Err] [Plugin.hh:187] Failed to load plugin libgazeborosopenni_kinect.so: libavdevice-ffmpeg.so.56: cannot open shared object file: No such file or directory [Wrn] [Publisher.cc:141] Queue limit reached for topic /gazebo/default/pose/local/info, deleting message. This warning is printed only once. [Wrn] [Publisher.cc:141] Queue limit reached for topic /gazebo/default/physics/contacts, deleting message. This warning is printed only once.

I followed the tutorial on this link to integrate Kinect with gazebo: http://gazebosim.org/tutorials/?tut=ros_depth_camera

When I try to install the missing library by sudo apt-get install, the output shows 'Unable to locate package'. Thank You. Any help would be appreciated.