Problem with LanczosResize

[Max_Schreck]

I recently encoded a movie using the LanczosResize plugin in my Avisynth script (for shrinking to 608 x 336). The problem is that it made all the letters in the credits look funny (lots of white dots around the letters). Is there anything I can do to avoid this?(besides using a different resizer). Thank you for your replies.

[UncasMS]

i'm using lanczos for quite some time now and that effect rather sounds like using different parameters in your codec.

did you by chance change the codec/its settings?

[Max_Schreck]

No, I'm using the same parameters for both passes and I haven't changed any of the advanced parameters default values. With BicubicResize the problem is much less noticeable.

[UncasMS]

your answer indicates, however, that the litle artefacts are present - only less visible because of slightly different sharpness.

are you using xvid by chance?
pretty much sounds like it.

if so which release and most important which settings?

[Max_Schreck]

Actually I'm using DivX 5.02 pro at 1200 Kbps with GMC and bidirectional encoding, no psychovisual enhancing, keyframe every 250 frames, al other settings at codec default value. Could it be Avisynth the cause of the problem? I'm using version 2.50 and the Mpeg2dec3.dll plugin, I did another test yesterday using BilinearResize and it solved the problem completely. Thank you for taking the time to look into this.

[The Edge]

You would get slightley better compression using BilinearResize. Even more so for credits. Is it possible to post your AVISynth script here?

Edge

[UncasMS]

i'm using avisynth 2.50 and 2.51 as well with divx 5.02

what i DONT use, however, is GMC because with gmc on i experienced ringing

make a small testrun WITHOUT gmc

bilinear is way to blurry for me.

i'd rather opt for lanczos + convolution3d

[The Edge]

Yes, convolution3d is a must have on most films.
Makes such a big difference when used correctlly.
I usually have it before resize filter. Where would one be without AVISynth!

Edge

[Max_Schreck]

I have found that already when I open my script in VirtualDub (before encoding!) the artifacts are there if use Lanczos or Bicubic, so I think it has everything to do with the resizing filter and not so much with gmc. I'm using VDMod 1.4.13. Here is my script if it is of any help

LoadPlugin("D:\Program Files\AviSynth 2.5\Plugins\Mpeg2Dec3.DLL")
LoadPlugin("D:\Program Files\AviSynth 2.5\Plugins\AutoCrop.DLL")
Mpeg2Source("D:\Road to Perdition\RoadTP.d2v")
#
#CROPPING:
#
AutoCrop(0,4,2,2,2,2,2,40,10,0)
#
#RESIZING:
#
LanczosResize(640,304)
#BilinearResize(640,304)
#BicubicResize(640,304)
#

[UncasMS]

your avs doesnt look much different to mine

maybe reinstalling avisynth 2.5 + the apropriate filters will help.

i am most satisfied with lanczos and so is almost any other user of this resizer.

[Max_Schreck]

I've found what the problem was. It seems my computer doesn't like the Lanczos - Mpeg2Dec3.dll combination. I switched back to the Mpeg2Dec.dll and problem solved, I can use Lanczos and Bicubic and there are no artifacts in the image, which is nice and sharp as it's to be expected with LanczosResize. It's too bad because my computer is old and slow (AMD K6 II) so I can use all the speed I can get and the Mpeg2Dec3 plugin did make a difference. I wonder if other people have experienced this same problem. Anyway, c'est la vie. Thank you Uncas and Edge for your help and suggestions, we'll see what new weird problem I can come up with the next time.