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Old 9th January 2002, 10:24   #1  |  Link
Narions
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soft bicubic better than Bilinear?

i always encode the movies using Bilinear in GK, but the last movie i mistaken and i use Bicubic instead of bilinear.
All movies i saw with bilinear (divx 4.0.2), i saw it blurry, difumimated , but the last movie (using bicubic) i saw it better colors. is this correct?
Using Bicubic enconding the movies, i'll see the movies with better colors than using Bilinear?
which is the difference about using bilinear or soft bicubic?
Sorry about my english and thanks.
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Old 9th January 2002, 13:19   #2  |  Link
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Simple answer : yes ! I dont use bilinear anymore since the 'modified' bicubic filters ( soft, neutral ) are around, they offer much better compromise between file size and crispness than Bilinear will.

This was different in former times when only precise bicubic ( = sahrp bicubic now ) and precise bilinear were options in Vdub ....
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Old 11th January 2002, 00:54   #3  |  Link
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decode

how bad then is breshnam filtering???
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Old 18th January 2002, 04:37   #4  |  Link
Mark Fredrickson
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Hey Christian,

Glad to see you're still getting around.

I'm curious about this debate over bilinear and bicubic with regards to DV camcorder videos. I'm in the NTSC world and I need to resize down from 720 to 640 and I've read that bilinear is better than bicubic at that. With your experiences with your DV cam and your little boy, what do you recommend?

I've only shot about 30 minutes so far with my DV cam of my children sledding and skiing so nothing is set in concrete yet. I'm still in the experimental phase while I continue to encode my 15 years of VHS videos.

Oh, btw, where do I get the 'modified' soft bicubic filters for VirtualDub? I've looked around and can't find anything other than precise bicubic.

Mark.

Last edited by Mark Fredrickson; 18th January 2002 at 07:58.
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Old 18th January 2002, 10:19   #5  |  Link
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Christian won't be around until at least the end of the month. He's spending most of his time at PowerDivX.com now though, so if you want to reach him, that's where you'll find him most likely.

Soft bicubic is not a filter in VDub, but a modified setting in Avisynth:
Soft Bicubic -> BicubicResize(x,y,0.333,0.333)
Neutral Bicubic -> BicubicResize(x,y,0.5,0.5)
Sharp Bicubic -> BicubicResize(x,y,0,0.75)
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Old 18th January 2002, 16:52   #6  |  Link
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I always use Sharp Bi-Cubic. Bilinear is too blurry. My DivXs come
out looking great...they aren't blurry, nor are they *too* sharp.

Prizm
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Old 18th January 2002, 17:03   #7  |  Link
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I always check if there is some noise and set sharpness against it
etc a noise movie with sharp bicubic will not look good better to use soft bicubic or neutral
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Old 18th January 2002, 20:15   #8  |  Link
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I don't know if he's working still on it, but tHE fISH from http://www.vdfilters.f2s.com/ has worked on new resizing filters for VirtualDub (I was one of those who bugged must about this ones )...

Algos like Lanczos, Hermite etc. are available... I have some beta version, don't know if he released any...

If you don't find it on his site, you can drop him a mail and beg him to work on it ;-) .

Cheers...
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Old 18th January 2002, 20:51   #9  |  Link
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Wouldn't neutral bicubic be the best, get the best of both worlds?

I've tried soft and sharp bicubic and they both seem fine. I noticed that on sharp, you can see greens better, like leaves on trees. I never tried neutral yet, but will on next encode.
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Old 19th January 2002, 15:39   #10  |  Link
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Greetings from China .... nothing can hinder me to post my little foolish comments here :

IMHO there is no general recommendation what resizing filter should be used, but GKnots recommendation is very helpful, so never use a sharp or even neutral bicubic for 'bits/pixel*frame' values < 0.22 - 0.23 .

I guess Super-Dividee and Steady should be able to comment on this with a better background than i have ....

@Mark : Bilinear should not be used for enlarging .... but this doesnt mean that bicubic should not be used for downsizing .... in fact its generally the better resizing filter and is to be preferred in most cases, unless you absolutely want a high resolution combined with a lower bitrate, resulting in a 0.16 bits/pixel*frame value or similar in GKnot ! BTW : Still no good results with DV capture, thanks to crappy Ulead software ( doesnt find my camera now ). Will test Adobe now ....
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Old 19th January 2002, 16:07   #11  |  Link
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Wow, you've found an internet access in China . DV and such, take a look at the postings on http://www.ultimateboard.de , MB1 and otheres have concentrated on DV in the last few months...

Quote:
Originally posted by ChristianHJW
Greetings from China .... nothing can hinder me to post my little foolish comments here :

BTW : Still no good results with DV capture, thanks to crappy Ulead software ( doesnt find my camera now ). Will test Adobe now ....
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Old 20th January 2002, 07:33   #12  |  Link
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bicubic

so bicubic is good for downsizing
bilinear good for upsizing
trilinear good for left sizing...
blah blah blah...

so whats best if u wanna retain the same resolution
(in my case standard PAL - 720x576)???
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Old 20th January 2002, 11:07   #13  |  Link
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Quote:
so bicubic is good for downsizing
bilinear good for upsizing
trilinear good for left sizing...
blah blah blah...
Actually the other way around. Bicubic->upsizing, Bilinear->downsizing.

Quote:
so whats best if u wanna retain the same resolution
in my case standard PAL - 720x576)???
Just crop, no resize. Just make sure you keep the resolution multiples of 16 and you'll be fine.
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Old 20th January 2002, 11:33   #14  |  Link
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ookay...
and if i was using flask xmpeg 4.2a? i have to choose something!
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Old 20th January 2002, 14:40   #15  |  Link
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In Flask always use HQ Bicubic Resizing. The others are baaaaaad.
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Old 20th January 2002, 20:19   #16  |  Link
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Ookami - I can't find any other resize filters on tHE fISH's filters site. So I'm stuck with the normal resize filters.

Can someone explain what 'precise' means (eg. precise bilinear, precise bicubic)?

I'm resizing my DV NTSC videos to 640x480. First, I crop to 704x480 (to get square pixels), then I resize to 640x480 (thanks Donald and Luke). I then will apply the correct resize filter. Any recommendations? How about Donald Graft's Smart Resizer?

Christian - Have you tried EditStudio (http://puremotion.com/index.htm)? It's DV capture function is superb and it doesn't require a license (the rest of the software does however).

Mark (Fredrickson).
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Old 20th January 2002, 22:22   #17  |  Link
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Hello Mark,

here's what Avery Lee writes in his VD help file (everyone should read that, IMO):

"Precise bilinear uses a full bilinear filtering kernel rather than a 2x2 and works for both reducing and enlarging pictures. When enlarging, this mode works similarly to bilinear, but when shrinking this filter averages many pixels together. This results in a much more faithful image and effectively squashes noise, even better than the 2:1 filter. Unfortunately, this filter mode is also slightly slower than bilinear mode when enlarging and signfiicantly slower when shrinking.

Precise bicubic uses a full bicubic filtering kernel rather than a 4x4. It works very similarly to precise bilinear, but the bicubic kernel produces sharper images, when either shrinking or enlarging. Shrinking a noisy 320x240 video with this filter can result in a sharp, clean 160x120 video. This filter is also the slowest of them all."

You can, of course, use Donald Graft's Smart resize, for instance, Wimpy use this one for his VCD guide (on Flexion.org).

Cheers,

Ookami.

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Originally posted by skyout
Ookami - I can't find any other resize filters on tHE fISH's filters site. So I'm stuck with the normal resize filters.

Can someone explain what 'precise' means (eg. precise bilinear, precise bicubic)?

I'm resizing my DV NTSC videos to 640x480. First, I crop to 704x480 (to get square pixels), then I resize to 640x480 (thanks Donald and Luke). I then will apply the correct resize filter. Any recommendations? How about Donald Graft's Smart Resizer?

Christian - Have you tried EditStudio (http://puremotion.com/index.htm)? It's DV capture function is superb and it doesn't require a license (the rest of the software does however).

Mark (Fredrickson).
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Old 23rd January 2002, 16:19   #18  |  Link
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I saw using bicubic filter (sharp): the images when the camera is filming the people near the objetive (faces of people almost filling all the screen), colors are cool and no sharped; but when the people are in second level i see unnatural faces (noise over the people, over the heads mainly).
How can i avoid it? can i use a filter combination to get the "wonderful" colors on first camera level and the same result in second level? (actually im using avisynth, but i dont care if i have to use full proccessing mode to get the best results)

by the way: if Gordian told me 0.14-0.16 bits/pixel*frame i must only use soft bicubic instead of sharp or neutral?(many of my movies are 640x272 and 640x352 and many of it are between 0.14-0.16). which filter i must use to get the best results (with bilinear i dont see sharpened forms but i got burryed colors.

Sorry about my english language and thanks.
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Old 23rd January 2002, 16:54   #19  |  Link
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Originally posted by skyout Christian - Have you tried EditStudio ? It's DV capture function is superb and it doesn't require a license (the rest of the software does however).
Hi Mark, downloaded it years ago, couldnt test it as it seems my firewire card is broken . Lately i had 100% CPU load whenever switching the camera on. Was searching like crazy, installs, reinstalls, deinstalls, etc. .... finally i found what the problem was : may only use the camera on battery, not power supply ....
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Old 24th January 2002, 08:19   #20  |  Link
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Ookami - Well, I guess this just proves how lazy I am. I never thought of just looking at the VD help. Thanks for pointing that out. I think that sometimes we get so use to just asking questions on these forums, that we forget that we actually have some resources quite near at hand.

Narions - Is the camera you are refering to a Camcorder or a Film Camera (eg. a DVD movie)? If it's a camcorder, then I'm quite interested as this is my area of interest, and if so, is your camcorder an analog or digital model? Also, you should never, and I repeat never, have to apologize for your English. I respect anyone who can speak and write in multiple languages. Unfortunately, here in America, we do not get the opportunity to practice multiple languages. My children all learn Spanish, French, or German, but they never get the opportunity to use it, so it is quickly forgotten (unless they get to go abroad). So be proud that you can communicate here. I went to a German forum on DivX and was totally lost, even though I've had 2 years of German in college (albiet a few years ago).

Christian - Ummm, doesn't quite make sense, does it? What does a power supply to a camcorder have to do with the firewire connection? I'm assuming that with the firewire connection being the only contact with the CPU, it must be the thing that is causing the 100% CPU load? Have you tried connecting your camcorder using the analog outputs? Or borrowing a friend's DV camcorder, or his firewire card? I'm guessing that with your engineering background, that you've torn your camcorder and computer apart and tried to hardwired them together ? Well, don't give up. You could be a real asset to those of us who are into camcorder encoding. I do believe that it is a bit different than DVD ripping (yes, no?).

Everybody - Well, I just encoded an hour of my DV home video (indoor family, bright snow sledding/skiing, dark indoor orchestra concert) using both VirtualDub's precise bilinear and precise bicubic (A=60) and for the life of me, I can't see any real differences. Mind you, I'm only resizing down from 704 to 640, so it's not a whole lot. Do you think I should be able to see any differences? And if so, how do I tell? Trying to flip back and forth between avi's is tough on the eyes. Any suggestions?

Thanks,

Mark.

Last edited by skyout; 24th January 2002 at 08:53.
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