WinFF is a GUI for the command line video converter, FFMPEG. It will
convert most any video file that FFmpeg will convert. WinFF does
multiple files in multiple formats at one time. You can for example
convert mpeg's, flv's, and mov's, all into avi's all at once.

lazarus is just a build-time dependency.

NOTE: if you have a previous ~/.winff directory you might want to
remove it or your presets might not be updated.
