I am using Blur(0,0.5) in avisynth for my lowpass filter, is it a good idea to sharpen afterwards? If so, what is the best thing to add to my code to sharpen my footage again after the blur?
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Last edited by katieburchett; 3rd Sep 2015 at 07:20.
I'm assuming we are talking about low-passing to reduce so called interline-twitter caused whenever a video is run through an interlaced playback chain.
Think of it like this: the purpose of low-passing is to make vertical details thicker so that they are not completely absent in either of the fields. That's not really the same as blurring vertical details.
Here is what I've been using for years for DVD menus, CG renderings and HD to SD conversions.
Blur(0, 0.6, false).Sharpen(0, 0.4, false) #mild, not for very detailed sources Blur(0, 0.7 false).Sharpen(0, 0.4, false) #medium, works well with almost any source in my experience Blur(0, 0.9 false).Sharpen(0, 0.5, false) #strong, try medium first
EDIT: I've just researched interline twitter, my footage is PROGRESSIVE (down-converted from HD to SD) but it definitely is exhibiting jagged Twitter along the horizontal lines. Is this normal for progressive material because Wikipedia suggests interline Twitter is caused by interlacing only? Should I still be using this low pass filter and sharpen? Thank you!
Last edited by katieburchett; 3rd Sep 2015 at 08:55.
Last edited by Skiller; 3rd Sep 2015 at 10:10.