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View Full Version : Bicubic vs Bilinear: Advanced Vdub User Puts his foot down


poopity poop
14th February 2002, 22:43
Many of you may know me, I encoded Kenshin on Dalnet and a bunch of other movies. Those of you who know me may be following my advice on encoding anime and how to get rid of noise in mpeg-2-->DivX conversions.

Currently I'm in the process of making an entire web page devoted to noise reduction, examples recommendations and settings. Its going to be very large and complete, I suggest you check it out in the comming weeks.

I have a problem:
As many of you may know, you should use prcise bicubic for enlarging, and prcise bilinear for reducing resolutions, this is the general concensus. Bilinear tends to smooth the image...just...slightly, and bicubic tends to sharpen it....just...slightly.
As I was accually testing all these methods of noise reduction (accually I'm in the middle of it while I right this) I came accorss something rather peculiar. Just for the fun of it I wanted to see how the results of these tests were changed if I changed the resize filter to bicubic before appliying the noise reducing filter. I was absolutly AMAZED at the difference. Then I thought I was just seeing things, so I brought the image over to photoshop and blew it up hue on my 19" moniter. Wow what a difference bicubic makes.

Now many will respond defending bilinear but I would like to introduce you to a quick website I just made showing the differences.
When you click on a link below, clikc on the picture to switch to bicubic, then again to switch back, then again to go to bicubic, etc, etc, and you may see the differences I noticed:
1. The edges are cleaner, tighter and darker
2. The detailed is not nearly as smeared
3. The large color expanses may have slightly more "noise" but...then again I'm just going to get rid of it by applying the many noise reducing filters I'm testing.

So I ask everyone? Why is bilinear better, when clearly(by the links below)that the three things listed above hold true

These links contain true, ENOURMOUS .bmps they will take a LONG time to load, let them load then keep clicking

http://web.syr.edu/~tjmyers/Precise_bilinear.html

dragoman
15th February 2002, 02:13
Hi,

In my experience (which, admittingly, is rather small....I've done about 30 rips of my DVDs so far), I find that you cannot make the statement that "bicubic/bilinear is better" and make it apply to every movie you intend to rip.

Certain movies require different settings. My personal choises are that for darker movies (the Matrix, unbreakable, etc...) bicubic works well. The sharp edges against the dark background look better, and the smearing affect on the walls tends to be faded into the darkness and not as noticeable. It seems to me that since bicubic builds bitrates around the edges of objects, flat walls and scenery tends to be blocky and indistinct.

This type of filter also lends itself well to shorter movies, say 1cd rips. By using less data on the background (walls, etc...) the picture is sharper, and the main focus of the movie (actors, etc..) are not blurry. Therefore the movie looks good on 1cd, and most viewers cannot tell there is anything different about the movie (especially at a lower monitor resolution).

For different movies, bilinear workds better. If you are making a 2cd rip, there is plenty of data to spare, and therefore the extra bits applied to make everything look smooth and continuous can be used. Bright movies tend to use bilinear better because in my opinion, bicubic on a bright scene (ex..football scenes in Any Given Sunday, a very hard movie to rip, btw...) makes things too distinct, giving the impression of blockiness around the edges of objects.

Ultimately, we all have our preferences as to what encoding paramters to use. I am simply saying that the use of one filter for all encodes (as I believe is the policy of our esteemed mentor, doom9 (neutral bicubic, is it?)) is not the best thing for ME.

dragoman

poopity poop
15th February 2002, 03:15
Yes I got a response from Ddogg explaining the same thing. So yes I beleive I am misaken a lot. But have a question:

What is the difference between the different bicubic filters? i.e. A=.6, .7, 1, etc?

sh0dan
18th February 2002, 20:23
see http://forum.doom9.org/showthread.php?s=&threadid=16142

movmasty
20th February 2002, 09:09
hi pop, im loading.....you could use as well jpg at 95/99% quality......

movmasty
20th February 2002, 09:41
ok, i just saw...............

poop, do this test:
1)take a beautiful girl
2)put her under a microscope
then, what do you see??
the same beautiful girl???

no!!! you will see germs!!!!!

note that not only every movie need its settings, but also the same movie u took the pic from could look better with bilinear!
as it is a movie,and not an enlarged pic!

take a shoot from a noised screen, you will see sharp noise.....

about your second question:
bilinear or bicubic mean nothing, must see how they are built.
those are different builds of bicubic that SHOULD go from a neutral bicubic(0.6) to a sharper one(1).

but, how you should see, they give almost always same results.
when we will see a true neutral bicubic in vdub???

poopity poop
21st February 2002, 00:06
I know, I know, I know, read my other posts.

Please stop responding to this trhread, its dead, I know what the deal is, I know what the options do better than I did before so I can make better decisions on higher quality encoing. This thread has been answered, thanks.

movmasty
21st February 2002, 07:47
np.......... :D