I tried to add png compression level into filepng.c But I did something stupid, and whole thing doesn't compile: root@slax:/dev/shm/tmp/cinelerra-goodguy-20200316/cinelerra-5.1/cinelerra# LANG=C make g++ `cat i686/c_flags` -DMSGQUAL=filepng -c filepng.C -o i686/filepng.o filepng.C: In member function 'virtual void PNGConfigVideo::create_objects()': filepng.C:370:49: error: no matching function for call to 'PNGConfigVideo::add_subwindow(PNGCompression*)' add_subwindow(new PNGCompression(this, x+50, y)); ^ In file included from /dev/shm/tmp/cinelerra-goodguy-20200316/cinelerra-5.1/cinelerra/../guicast/bcsubwindow.h:26:0, from /dev/shm/tmp/cinelerra-goodguy-20200316/cinelerra-5.1/cinelerra/../guicast/bcbar.h:26, from /dev/shm/tmp/cinelerra-goodguy-20200316/cinelerra-5.1/cinelerra/../guicast/guicast.h:27, from edit.h:30, from filepng.C:23: /dev/shm/tmp/cinelerra-goodguy-20200316/cinelerra-5.1/cinelerra/../guicast/bcwindowbase.h:276:17: note: candidate: BC_WindowBase* BC_WindowBase::add_subwindow(BC_WindowBase*) BC_WindowBase* add_subwindow(BC_WindowBase *subwindow); ^ /dev/shm/tmp/cinelerra-goodguy-20200316/cinelerra-5.1/cinelerra/../guicast/bcwindowbase.h:276:17: note: no known conversion for argument 1 from 'PNGCompression*' to 'BC_WindowBase*' At global scope: cc1plus: warning: unrecognized command line option '-Wno-stringop-truncation' cc1plus: warning: unrecognized command line option '-Wno-format-overflow' cc1plus: warning: unrecognized command line option '-Wno-format-truncation' cc1plus: warning: unrecognized command line option '-Wno-stringop-overflow' cc1plus: warning: unrecognized command line option '-Wno-unknown-warning-option' make: *** [i686/filepng.o] Error 1 patch attached ....