Accessing frames in loaded SWF

Hi. I have a SWF that I am loading dynamically. I want to be able to grab a single frame out of the SWF. Assume the SWF contains something like an FLV movie.

The use case here is related to bit blitting. I have many dynamic SWFs that were originally built assuming they would be played as movieclips. But now I am experimenting with using AS3’s bit blitting routines. We could rebuild the original SWFs to export individual PNGs for each frame (for each layer), but it seems to me that somewhere Flash must maintain a list of frames for every “movie” it has loaded. Using the debugger I can’t seem to see the frames.

All help is appreciated!