First frame skipped when rendering

[shrubbyfrog]

I have a good feeling this program isn't maintained anymore, but I will try my hand at this nonetheless.

When rendering a ,swf file, the first frame of video is consistently chopped off, while the audio (if any) remains intact. It's barely noticeable with higher framerates, but it's more apparent with lower framerates, and contributes to de-sync in the rendered output.