(Edited to add image)
I've noticed that a certain minority of FLV files look funny when played by VLC (my system is OS X, ppc). Namely, there are lots of horizontal color bars that appear and disappear constantly.
I'm wondering if this is platform-specific or not. Please test the following file:
http://video.ted.com/talks/embed/BrianC ... d_high.flv
(I just fixed a very similar bug in MPlayer which may have been somewhat platform-specific. The trouble is that I'm not sure exactly of the root cause, except that it's definitely NOT in ffmpeg. I only fixed it by disabling a certain kind of rendering. (I think that's what it was-- you know how you can sometimes fix something by tinkering around without knowing precisely what everything does?))