SWF – How to Play .swf Files

There is a way of getting this done explained in the Floorplanner Tech Blog. To compile dump-gnash on a fresh Maverick you'll need

sudo apt-get install gcc libboost-dev libboost-thread-dev libagg-dev libsdl1.2-dev libcairo-dev libgstreamer0.10-dev libatk1.0-dev libglib2.0-dev libpango1.0-dev libgtk2.0-dev libgtkglext1-dev libgl1-mesa-dev libgif-dev libjpeg-dev libgstreamer-plugins-base0.10-dev libspeex-dev libcurl-dev

And then you just follow the steps. This will take a long time.
NOTE: For Step 7 use the following script instead:

if [[ $3 ]]; then
    raw="$(mktemp)"
    dump-gnash $2 -P "FlashVars=url=file://$1" -D "$raw" --max-advances 1 -j 500 -k 500
    tail -c 1MB "$raw" | convert -size 500x500 -depth 8 rgba:- -separate -swap 0,2 -combine -trim png:"$3"
    trap "rm $raw" EXIT
else
    echo "Insufficient arguments (expected 3 arguments)"
    exit 1
fi

Once you have the final script running you just hook it into gconf-editor

gconftool-2 -s "/desktop/gnome/thumbnailers/application@swf" -t string "/usr/bin/swfthumbnailer.sh %s %i %o"
gconftool-2 -s "/desktop/gnome/thumbnailers/application@swf/enable" -t boolean 'true'
gconftool-2 -s "/desktop/gnome/thumbnailers/application@x-swf" -t string "/usr/bin/swfthumbnailer.sh %s %i %o"
gconftool-2 -s "/desktop/gnome/thumbnailers/application@x-swf/enable" -t boolean 'true'
gconftool-2 -s "/desktop/gnome/thumbnailers/application@x-shockwave-flash/command" -t string "/usr/bin/swfthumbnailer.sh %s %i %o"
gconftool-2 -s "/desktop/gnome/thumbnailers/application@x-shockwave-flash/enable" -t boolean 'true'

Then restart (or restart gnome-settings-daemon), and you've got swf thumbs!

P.S.: This is a huge hack. A better way to do this would be vastly appreciated.

You can decompile, edit, and recompile SWF using swfmill. This tool turns a SWF into XML and back again, e.g.:

swfmill swf2xml movie.swf movie.xml

swfmill xml2swf movie.xml movie.swf

However, whether this will be useful to you depends on how the SWF is put together. You can edit images, videos, audio etc within the movie using this method. They are present in the XML file as base64 encoded blocks which you can replace.

Editing text is much harder because text in SWF files is usually converted to curves so that the fonts do not need to be embedded.