FFmpeg command generator for trimming and transcoding videos

So you have some long video that you wish to trim down to just a few minutes somewhere in the middle without adding or doing anything else to that video. For such a simple task, there is no need to mess with some fancy video editor. The only tool you will need for this is FFmpeg, which can be downloaded from here: https://www.ffmpeg.org/download.html.

FFmpeg is a very useful command line tool to have around that is capable of many things, but for our purposes here we are only interested in trimming a particular video to some specified interval, and then optionally transcoding it according to best youtube standards.