[FFmpeg-user] Extracting images from swf using ffmpeg (version 8 swf vs version 10)

[Ryder Wright]

Hi all,

I have a collection of swf files, some of which are version 8 and some are
version 10. I want to create animated gifs from these files.

I've established that I can obtain a collection of images from the version
8 swfs using:
  % ffmpeg -i $swf -f image2 -vcodec png -r 30 i%02d.png
but when the above is invoked on version 10 swfs, I get an error:
  could not find codec parameters

When I invoke 'swfextract' on a version 8 image, I get something like:

% swfextract a.swf
Objects in file a.swf:
 [-i] 6 Shapes: ID(s) 2, 5, 9, 11, 13, 16
 [-i] 2 MovieClips: ID(s) 10, 17
 [-f] 1 Frame: ID(s) 0

When I invoke 'swfextract' on a version 10 image, I get something like:

% swfextract b.swf
Objects in file b.swf:
 [-i] 1 MovieClip: ID(s) 3
 [-F] 1 Font: ID(s) 2
 [-b] 1 Binary: ID(s) 1
 [-f] 1 Frame: ID(s) 0

No shapes, just a single MovieClip (and a Font).

Questions:

   - Anyone know why ffmpeg works for version 8 swf files but not version
   10 files?
   - Why does one specify a format type of 'image2' (as opposed to 'swf' or
   'avm2')?
   - Is there a way to extract images from a version 10 swf file using
   ffmpeg?

Thanks,
Ryder