Lanczos3 Filter Resize.

[OUTPinged_]

didee,

resizing algorithms dont produce EE.

sharpeners like unsharpmask and msharpen do.

too sharp resize results in aliasing tho (but that is not EE)

[Didée]

Marc,

I see nothing to correct.

My finding "(-0.1, 0.5) very similar" referred to the pretty limited range we usually deal with: when resampling sources like DVD/TV-caps, destination size is usually >=50% for downscaling, resp. =<150% for upscaling. For these ranges, no alien algorithms are needed ;)

I thought the Bicubic resampler ignores b<0 and uses b==0 instead.
EDIT : I'm really not sure of this...That´s what I read, but ... it seems to be fixed: try it out.
There were some optimizations to the resize algorithms in AviSynth 2.05 & 2.06, maybe s'one has touched s'thing in there?

[sh0dan]

Can't see any range checking on b/c in the current code, and I haven't implemented it, and I don't think dividee has changed it either.

The only thing that have changed qulitywise is:

- Proper rounding in yuy2 mode
- Picture offset by 1 pixel in RGB mode.
- Chroma wrap problems corrected.

The rest of the code produces similar results as always.

[CHAOSMAN33]

im still a bit confused about how to use the lanczos resize. For the script command, what values must be entered in, the documentation says

LanczosResize(clip, int target_width, int target_height)
LanczosResize(clip, int target_width, int target_height, float "src_left", float "src_top", float "src_width", float "src_height")


which do i use the first or second, and what values must i enter in, sorry im a gknot newbie, and dont have much experience in editing.

[JohnMK]

Forget about all that, just use:

LanczosResize(640,480) or whatever your resized res is.

[wing1]

hmmmm did not know that you can crop during resizing with lanczosresize function. The original dll doesn't allow such an option. I Need to read the documentation more often with each new releases :D.

@chaosman33

1st option just simply resizes to whatever you would like for the output to be (x,y)->(640,480). i.e. lanczosresize(640,480)=> resize whatever the source is to 640(width)x480(height).

2nd option allows you to crop the source as you resize at the same time. i.e.
(x,y,left,top,right,bottom)->(640,480,0,0,last.width-8,last.height-16). If Source frame size = 704x576, then you will be cropping 8 pixels off from the right side of the frame and 16 pixels off from the bottom of the frame. Afterward, you would resize the crop result to be what you specify as output x,y.

doing this

lanczosresize(640,480,0,0,last.width-8,last.height-16)

and this

crop(0,0,last.width-8,last.height-16)
lanczosresize(640,480)

are the same.

[CHAOSMAN33]

thanks for the clarification wing1 ;)

[ChannelK]

Sorry to ask a propably stupid question, but, i've looked and I cant seem to find where to get the latest (if there is a latest) Lanczos resize filter.

Any links?

(a convolution3D link would also be appreciate)

Thanks.

[sh0dan]

Lanczos is built-in from 2.06 and newer versions. No need for a plugin.
Look at avisynth.org (http://www.avisynth.org) for all the filters you can imagine.

[Iznogoud]

"warning!
This question may appear foolish to more advanced users"

@wing1
So I tried it and works

LanczosResize(544,304,8,74,704,428)
and
crop(8,74,704,428)
LanczosResize(544,304)

are the same, just wonder if there is something to gain or lose using the first method?

[Didée]

Iznogoud,

both variants work identical, but differ in speed.
In an encoding of several hours, you might either win or loose some ... seconds.

In addition, there was a discussion wether the cropping-within-resizing should be maintained or dropped in upcoming AviSynth versions - but I don't know what the status is there.

[Boulder]

Separate cropping is useful when you want to use filters before resizing. They'll be faster if you crop first, then apply the filters and then resize. No need to smooth those pixels that get cropped off anyway;)

[Iznogoud]

@Didee

Mmmmmmmm, seconds... (thinking in Homer-style)

@Boulder

Kiitos

[sh0dan]

Having "cropping within resizing" is a bit silly, but it's there for compatebility. Always use crop - it's faster and has more features.

[Iznogoud]

It is good now:) Thanks for clear answers!

[jarthel]

I've had problems with the following combo

temporalsmoother -->> lanczos = problem (use simpleresize instead no problem)

temporalsmoother -->> SShiQ -->> lanczosresize = problem (use simpleresize instead no problem)

temporalsmoother -->> 2DCleaner -->> lanczosresize = ok :)

jayel

[3ngel]

Lanczos3 has a terrific quality!
Some great guy out of you, can make a DirectShow Filter porting of this resize filter?
It would be great to include a Lanczos Resize Filter in a Graphedit chain! :eek:
Please! :rolleyes: ;)

[MoonWalker]

Try ffdshow..It has many kinds of resizing(lanczos too)..

MoonWalker

[Wilbert]

Sorry for being OT, but I have to ask this :) Couldn't you find an older thread?

[Blue_MiSfit]

No kidding! I started reading the first post and had to read it like 3 times before it actually connected that I was reading a 3 year old thread before avisynth had lanczos resizing built in! :O Now we even have the uber lanczos4resize.

Avisynth just kicks so much ass its ridiculous!!

~Misfit

[3ngel]

@Moonwalker
Mmm.. ok i'll try, thank you.

At this point another question : but ffdshow can integrate even avisynth commands?