Create a .gif from video

This command line should work but will generate a giant file:

ffmpeg -i yesbuddy.mov -pix_fmt rgb24 output.gif

Note that you probably want to reduce the frame rate and size when you convert, as well as specify a start time and duration. You probably do not want to convert the entire file at its original resolution and frame rate.

ffmpeg -ss 00:00:00.000 -i yesbuddy.mov -pix_fmt rgb24 -r 10 -s 320x240 -t 00:00:10.000 output.gif

The file size will still be huge. You may be able to use ImageMagick's GIF optimizer to reduce the size:

convert -layers Optimize output.gif output_optimized.gif

Source: http://superuser.com/a/436109