The FFmpeg site is currently slow/closed. Perhaps too many OpenToonz users are trying to download FFmpeg. ;)
Be patient and the site will eventually open.
The recently released v1.1 of OpenToonz includes the option for Integrated FFmpeg for import/export mp4, webm and gif formats.
Some folks might be a little confused when those formats don't show up in the menu so I thought I might post some information on how to get access to those formats.
FFmpeg is not distributed with OpenToonz so you'll need to download and install it and point OpenToonz to it in the preferences.
Any of the various flavors of FFmpeg should work but I've been using the portable release because that one doesn't even need to be installed.
Just place it in the desired location and let OpenToonz know where you put it.
For Mac users... follow those links.
Steps to get FFmpeg support up and running:
Downlaod FFmpeg and note that location where you install the binary/executable:
Open OpenToonz
Go to File/Preferences
Go down to the Import/Export listing
Follow the instructions that appear to point OpenToonz to the folder where you placed the binary/executable.
For instance if you downloaded it to C:\Program Files\FFmpeg navigate to that location.
For the portable I am using I needed to go there and then click on the 'bin' folder that contains the program.
Close out the Preferences
Close OpenToonz
When you start OpenToonz again you should have the new formats available.
Not clear on those steps?
I'm sure a video tutorial or two will be forthcoming. :)