[Swftools-common] swfextract does not detect frames

[Max Pimm]

I have a very simple flash movie with several frames on the root 
timeline, each of which contains a bitmap. I want to split this movie by 
frames and swfextract would seem to be exactly what i'm looking for.

However when i issue

swfextract mypdf.pdf

I get:

[-i] 9 Shapes: ID(s) 2, 4, 6, 8, 10, 12, 14, 16, 18
[-p] 9 PNGs: ID(s) 1, 3, 5, 7, 9, 11, 13, 15, 17
[-f] 1 Frame: ID(s) 0

Why does it not detect the frames? Have i misunderstood something?

Max