This section describes how the FFmpeg options files work for decoding and encoding and goes into great detail. It will make more sense if you look at CINELERRA-GG's ffmpeg config directory and the CINELERRA-GG menus at the same time. It is meant to include everything necessary for complete understanding. You will be able to personalize your own options files without knowing all of the information included below if you know the basics. The word encoding is used interchangeably with the word rendering. The possible combinations for ffmpeg options files are literally combinatorial – that is a lot (factorial!). The allowed media file format / codec choices are much more flexible than you might realize. When the ffmpeg design was initially added, some parameter files which describe the choices which the program uses had to be created. There are way too many to enumerate in the deliverable CINELERRA-GG package. Some quite detailed information for how ffmpeg options work is given here and hopefully, enough basics for simple understanding. It may all seem complicated at first, but will become obvious. AppImage does not provide this capability unless you use the workaround as described in the Appendix FAQ, Known Problems and Workarounds.