[bouqueau] forbid mp4box with a unique input file as arg as it makes nothing...
[bouqueau] forbid mp4box with a unique input file as arg as it makes nothing...

DmitrySigaev/gpac-sf,DmitrySigaev/gpac-sf,DmitrySigaev/gpac-sf,DmitrySigaev/gpac-sf,DmitrySigaev/gpac-sf,DmitrySigaev/gpac-sf