Spend a day playing with recaptcha. Posting this here so it wasn't all for nothing.
You can get the ffmpeg.exe from here: https://www.ffmpeg.org/
https://www.ffmpeg.org/download.html
https://ffmpeg.zeranoe.com/builds/
I used this one: FFmpeg git-b3eda69 64-bit Static
https://ffmpeg.zeranoe.com/builds/win64/static/ffmpeg-20160401-git-b3eda69-win64-static.7z
(Note from Dec'17): Sorry for my use of explode instead of handling the json properly. I just didn't care at the time.