How to install libqt4-core and libqt4-gui on Ubuntu 16.04 LTS?

These libqt4-core and libqt4-gui packages don't exist anymore in Ubuntu 16.04 LTS and newer. They were dummy packages with dependencies to other packages. The following procedure will modify the Vidyo package so it uses working dependencies.

1. First make sure that all required libqt4 packages not installed by default are installed:

   sudo apt install libqt4-designer libqt4-opengl libqt4-svg libqtgui4 libqtwebkit4
   

2. Create a script to modify the dependency defined in the package. Use the videbcontrol script provided here.

3. Run the script videbcontrol VidyoDesktopInstaller-ubuntu64-TAG_VD_3_6_3_017.deb that will open the dependencies in a vi editor

4. Replace Depends: libxss1,libaudio2,libasound2,libqt4-gui (>= 4.8.1), libqt4-network with Depends: libxss1,libaudio2,libasound2,libqt4-designer,libqt4-opengl,libqt4-svg,libqtgui4,libqtwebkit4,libqt4-network. This creates a file named VidyoDesktopInstaller-ubuntu64-TAG_VD_3_6_3_017.modified.deb containing the new dependency.

   If you don't know vi, once you see the package information

   1. move the cursor using the arrows down to the line starting with Depends:
   2. type the letter i to get into insert mode
   3. copy past (right click) the new line and type return
   4. type escape to leave the insert mode
   5. type dd to delete the old Depends line
   6. type ZZ to save and quit the change (two upper case z)

5. Install the Vidyo package by executing the command:

   sudo apt install VidyoDesktopInstaller-ubuntu64-TAG_VD_3_6_3_017.modified.deb
   

Enjoy

Thanks to https://ubuntuforums.org/showthread.php?t=110458 and @chmike These dependencies already have higher versions as I found. It is okay to change the .deb file instead. @bean1975 has a shorter method:

dpkg-deb -x yourfile.deb newdir 
dpkg-deb --control yourfile.deb newdir/DEBIAN
gedit newdir/DEBIAN/control

and change the libqt4-gui (>= 4.8.1) with libqt4-designer,libqt4-opengl,libqt4-svg,libqtgui4,libqtwebkit4

dpkg -b newdir modified.deb

and you can use it now!!!