Beware : am not a lawyer, if this question is intended for a serious production, you should seek legal advice from a specialized lawyer.
FFmpeg has parts that are LGPL, GPL, and 3rd party libraries (e.g libx264, libmp3lame..) have their own licenses too.
The legal checklist you linked at actually seems suited for a commercial application. The most important parts are not compiling with either --enable-gpl
or --enable-nonfree
and linking your program dynamically to the libraries.
This will automatically disable any codec whose code license is incompatible with a closed-source binary release, for example GPL.
If your commercial application is going to be open-source, then you may use --enable-gpl
.
Please note that you are under obligation to release the FFmpeg's LGPL source code that you used, including any modifications you might have done directly to it.
Finally, if your program will allow the end-user to encode with patented formats (H.264, AAC [..]), you should do your homework on the laws concerning patented software in your jurisdiction, as the MPEG-LA may come knock at your door.