ffmpeg is a free, open-sourced, command line tool that can be used to, among other things, encode and decode media.
Installation
Download a compiled (gpl, non-shared) version of ffmpeg and unzip the contents
Links to compiled versions of fffmpeg, for various operating systems, are available in the download section of the official ffmpeg.org website (in the Get packages & executables files section).
Copy ffmpeg.exe (Windows) or ffmpeg (macOS) to a location on your hard drive
In Zurbrigg Advanced Playblast, select the Settings tab
In the Playlast section, set the ffmpeg Path to the location of the executable on your hard drive