I want to extract a few seconds from an AVI file then put the extracted video into an animated GIF.
I don't know the codec - I couldn't be bothered to find out. But VLC Media Player plays it just fine.
You will shit yourself laughing when I post the GIF. As the Men's Wearhouse guy sez: "I guarantee it".
It doesn't have to happen all in one tool.
If it's any help I own a paid copy of GIF Converter for Mac OS X. "GIF Converter" is quite a suggestive name, but even if it would do all the work for me, I still can't be bothered to look up how it's done.
I also have a working MacPorts installation.
If you're desperate, I could also used Windows 8.1 or - when I de-bork my borked installation - Devuan Linux.
(I don't use Linux Mint anymore because version 18 includes systemd.)