* in_ffsox-2a-0.6.0.exe is the plug-in's NSIS (http://nsis.sourceforge.net/) based installer containing also tiny versions of the needed third party DLLs. You should update especially avcodec-58.dll and avformat-58.dll following the instructions from the project's homepage at http://in-ffsox.sourceforge.net/#installation. * in_ffsox-2a-0.6.0.dll.7z contains the bare plug-in without any third party DLL which you need to install yourself following the instructions at http://in-ffsox.sourceforge.net/#installation. * in_ffsox-2a-0.6.0-src.tar.gz contains the plug-in's sourcecode. * in_ffsox-2a-0.6.0-src-foreign.tar.gz contains the plug-in's third party source code especially the FFmpeg snapshot for which this plug-in version was compiled.