[MPlayer-users] Extract Segments By Specifying Frame Range?

[Hibiki Kanzaki]

I would like to extract a segment from a video by specifying
a range of frames, like 1440-2800; it is ok if I can only
specify keyframes like from -vf framestep=I.  I want the audio
and video, so I can play just that fragment.  Kind of like
with -ss and -endpos, but specifying frames instead of seconds.

Is there a simple way to do this?  It does not have to be
using mplayer or mencoder; it could be ffmpeg or whatever.