_,,,^..^,,,_ said:
... Infact, if I capture PAL video, the resulting file is everytime 720x576 at 25fps; so VirtualDub make a deinterlace (seems blending to me, don't know for sure).
...
This is correct, your capture should always be 720x576 25fps. If you don't see any combing, then it's because your source is progressive.