Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion.

Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules.

 

Go Back   Doom9's Forum > Capturing and Editing Video > VirtualDub, VDubMod & AviDemux

Reply
 
Thread Tools Search this Thread Display Modes
Old 7th January 2003, 01:45   #1  |  Link
junglemike
Registered User
 
Join Date: Dec 2002
Posts: 288
Difference between Resize filter mods?

Hi everyone, I was playing with Resize filter in Dub. it has
Nearest neighbor,bilinear,bicubic and other mods.
Can anyone explain what is the difference between them.
I heard that come "rise" compressibility of file, but reduce quality(starirs effect) or vice versa. Is there some method that is good for visual quality and for compressibility too? And Is there some external filter that does it better, or just in other way?
Any help is appreciated.
junglemike is offline   Reply With Quote
Old 7th January 2003, 09:14   #2  |  Link
hakko504
Remember Rule One
 
hakko504's Avatar
 
Join Date: Oct 2001
Location: SWEDEN
Posts: 1,611
To begin with you can always read the help file in VD. It is explained quite well there.
__________________
/hakko

http://www.boardgamegeek.com
hakko504 is offline   Reply With Quote
Old 8th January 2003, 02:45   #3  |  Link
^^-+I4004+-^^
Banned
 
^^-+I4004+-^^'s Avatar
 
Join Date: Aug 2002
Location: Croatia [local name:Hrvatska]
Posts: 551
"Precise bicubic uses a full bicubic filtering kernel rather than a 4x4. It works very similarly to precise bilinear,......."

>To begin with you can always read the help file in VD. It is explained quite well there

yes,now he (same as me) knows a whole helluva more about resizing than before....LOL!

no,those are not good explanations.....
those explanations are from developer to developer....
^^-+I4004+-^^ is offline   Reply With Quote
Old 9th January 2003, 02:13   #4  |  Link
Evil Andy
Registered User
 
Join Date: Nov 2002
Location: Cheshire, England
Posts: 76
K, I'm a little pickled so I don't know how coherent this will be...

Let us consider a picture being resized down by an arbitrary amount. Therefore each pixel in the final picture will be equivalent to several pixels or part of pixels from the starting picture.

Nearest neighbour is the fastest algorithm because it chooses the pixel that would be closest to the original, spatially, if you scale up or scale down an image with no reference to the colour of the surrounding pixels e.g. if you have 9 pixels arranged thus

1 2 3
4 5 6
7 8 9

and you scaled the image down to a third of its size then the resultant pixel would be the same colour as pixel 5 regardless of the surrounding pixels.

Bilinear takes all the source pixels that make up the new pixel and gives a weighted average of their colour to find the final colour. It does this in a linear way ie. a pixel twice as far away has half the weight, a pixel four times as far away has a quarter the weight etc. so a graph of proximity versus weight gives a straight or linear line.

Bicubic is the slowest algorithm as pixels have exponentially more weight the closer they are to the nearest neighbour pixel so a graph of proximity versus weight gives a curved line.

And that all seems to make sense after 7 pints. Stand by for an edit in the morning when I realise I'm talking total rubbish

Last edited by Evil Andy; 9th January 2003 at 03:29.
Evil Andy is offline   Reply With Quote
Old 9th January 2003, 02:20   #5  |  Link
Evil Andy
Registered User
 
Join Date: Nov 2002
Location: Cheshire, England
Posts: 76
To answer your other question, as a general rule of thumb bilinear should for the most part give the best compression as it throws away the most detail and bicubic should give the worst compression as it keeps the most detail Andy said as he slid drunkenly under the table
Evil Andy is offline   Reply With Quote
Old 9th January 2003, 21:09   #6  |  Link
fccHandler
Registered Jedi
 
Join Date: Jan 2003
Location: Georgia, U.S.A.
Posts: 733
From my experience, "Precise bilinear" compresses the best of any mode, but it's a bit blurry. "Precise bicubic (A=-1.00)" is the sharpest, but it produces more "ringing" artifacts.
__________________
May the FOURCC be with you...
fccHandler is offline   Reply With Quote
Old 11th January 2003, 05:05   #7  |  Link
^^-+I4004+-^^
Banned
 
^^-+I4004+-^^'s Avatar
 
Join Date: Aug 2002
Location: Croatia [local name:Hrvatska]
Posts: 551
to be precise,"ringing" is produced by codec,not resizer.......

bicubic is sharper,that's why.....
^^-+I4004+-^^ is offline   Reply With Quote
Old 16th January 2003, 01:40   #8  |  Link
Asmodian
Registered User
 
Join Date: Feb 2002
Location: San Jose, California
Posts: 4,406
I though bicubic on something as sharp as -1 produced it's own ringing artifacts, which is the reason lanczos resize exists?
Asmodian is offline   Reply With Quote
Old 16th January 2003, 04:44   #9  |  Link
fccHandler
Registered Jedi
 
Join Date: Jan 2003
Location: Georgia, U.S.A.
Posts: 733
No, he's right. It's the codec.

IIRC Lanczos was added only because so many people requested it. Avery Lee said that he couldn't see any difference at all. (I agree.)
__________________
May the FOURCC be with you...
fccHandler is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 10:09.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.