Frames were sampled.

90 of 473 sprites have more than 24 frames. For those, 24 evenly spaced frames spanning the whole timeline were rendered instead of every frame.
Files are numbered by their position in the sampled sequence, not by their original frame number.

Rendered at 0.5x scale.
Raise -Ddecompiler.swf.maxFramesPerSprite and -Ddecompiler.swf.spriteZoom to export more.