sudo gedit /usr/share/applications/avidemux-gtk.desktop added %U in the line Exec=avidemux2_gtk that is Exec=avidemux2_gtk %U it worked
sudo gedit /usr/share/ applications/ avidemux- gtk.desktop
added %U in the line Exec=avidemux2_gtk
that is
Exec=avidemux2_gtk %U
it worked