I was talking the A/V tech person who recorded FediCon.
He told me he would run all the videos he recorded of FediCon through Handbrake, to reduce their size, before giving them to me.
I.e., Handbrake the open-source video transcoding tool.
Which I thought was interesting. That (at least one instance of) open-souce software is part of his A/V tool-set.