Shell Programming and Scripting

I need to output a summary of a video as an animated gif. Ideally, I would have 8 equally-spaced frames from the video, and play them back one at a time, each for 0.25 seconds. So I'd have a 2 second animated gif.

This is what I have so far:

Code:

#!/bin/bash
mplayer "$@" -vo gif89a:output="$@".gif:fps=1 -vf scale=640:480 -endpos 8 -really-quiet

As you can see, I'm taking eight frames from the first eight seconds of video. What can I use to take eight frames from $timeOfVideo/7 time periods. Note that I'm dividing the time of the video by 7, not 8, so that I will have the first and last frames of the video in the gif.

My second problem is shortening the duration that each frame is shown. Currently, each frame is shown for 1 second. How can I reduce that to 0.25 seconds?

I am starting to think that ffmpeg is a better tool for the job, however, surprisingly I cannot find relevant examples in Google. Can ffmpeg do what I need? Can mplayer, for that matter? Something else?

Thanks in advance.