If there's no existing solution in Perl, and you can find a non-Perl tool that does this, it might be simplest to call this tool from Perl (if it's a command line tool) or "remote control" it from Perl (if it's an interactive tool).

I don't know of any modules that do this.

There is a free Java image processing program ImageJ which has a Quicktime Still Extractor plugin that should do what you need. Happily, ImageJ can be run as an image processing toolkit applet or servlet, so should be easy to call from perl.

I ended up going with mplayer - which can be quite an adventure to compile with QuickTime support - and calling it as a command line program. There is an FFmpeg module, but I had trouble getting it to compile on my dev server.