I actually got Format factory to work quite well. I used the MOV option with H264 inside, but I'll try flvextract as well just to se if the quality is even better...
As with all containers, there are different flavors of FLV. The handling of FLV/h264, for instance, is quite different than working with FLV1, which can be h263, Sorenson, VP5, etc.
Best thing to do would be to post a short clip somewhere and let us try some things. Then you can pick the solution that works best for you.
Ulf,
Here's a way to get a true lossless conversion using Super that will import to Vegas.
[1 AVI
[2 Raw Uncompressed
[3 WAV pcm 16
-- Select MEncoder
-- Select DirectShow decode
-- Select "More" for Frame Rate and type in 24
-- Select 22050 for your audio (that's what your file is)
-- Click "No" when it asks you if you want to switch to ffmpeg
This will give you a huge, visually perfect file (I wasn't able to get huffyuv working correctly in either Super or AVIDeMux).