So, If c = 5, I must set b to -9 (1-2*5) in order to get accurate filter effect, is that right? I'll try it later. Thanks for your explaination. By the way, I don't care about ringing that much since it's not that noticable when watching from an appropriate distance. Have you encoded a movie using 100% quality-based method at full resolution, along with Vdub's sharp filter at maximum strengh (64)? I was totally shocked when I first saw the result. Someone may say "those details are fake", but at least they fake it beautifully. It's like you're watching a 3-D movie.