#OS X Movie to animated GIF
ffmpeg -i movie-name.mp4 -s 600x400 -pix_fmt rgb24 -r 10 -f gif - | gifsicle --optimize=0 --delay=3 > movie-name.gif
##Options
-r 10
tells ffmpeg to reduce the frame rate from 25 fps to 10-s 600x400
tells ffmpeg the max-width and max-height