Strange avisynth artifacts

[cayblood]

I'm having a very frustrating problem with avisynth. To reproduce my issue, download the following two files:

http://youngbloods.org/video/test.avs
http://youngbloods.org/video/advert.avi

All the script does is open the AVI file with AVISource(). On my machine, if I open the avi file directly and play it, everything looks fine. However, if I open the avisynth script and play it instead, a number of small colored lines and artifacts begin to appear in the logo and get more and more distinct as the video plays further.

It seems that avisynth is introducing these annoyances. I am at my wit's end trying to get rid of them. I've tried installing different versions of avisynth, to no avail. Any help would be greatly appreciated.

Thanks,
Carl

[cayblood]

Here are screenshots from the normal avi and the avi rendered by avisynth:

NORMAL:
http://youngbloods.org/video/normal.jpg

RENDERED IN AVISYNTH:
http://youngbloods.org/video/in_avisynth.jpg

Any ideas?

[Dark Shikari]

I'm going to guess when you're playing the AVI file, you're using Directshow, and when you're AVIsourcing it, you're using Video for Windows. For the former you probably have a working decoder, for the latter I'm going to guess you don't.

Use DirectShowSource instead.

[Guest]

I open the AVI in VirtualDub directly and I see the same artifacts as I see when I open the script.

So, what do you mean by "if I open the avi file directly and play it"?

[cayblood]

I'm going to guess when you're playing the AVI file, you're using Directshow, and when you're AVIsourcing it, you're using Video for Windows. For the former you probably have a working decoder, for the latter I'm going to guess you don't.

Use DirectShowSource instead.

You're a genius!!!! Thanks.

[cayblood]

I'm going to guess when you're playing the AVI file, you're using Directshow, and when you're AVIsourcing it, you're using Video for Windows. For the former you probably have a working decoder, for the latter I'm going to guess you don't.

Use DirectShowSource instead.

Incidentally, do you have any recommendations for how I can get VFW working properly?

[setarip_old]

@cayblood

The artifacts also appear when simply playing the .AVI directly in good ol' Windows Media player v.6.4...

[Guest]

Failed for me with DirectShowSource, too.

EDIT: Forced libavcodec in ffdshow and it played clean.

[mikeytown2]

it's a Divx 5 file so can't xvid's decoder handle it?

[Dark Shikari]

it's a Divx 5 file so can't xvid's decoder handle it?Don't you just love DCT mismatch? :)

[squid_80]

it's a Divx 5 file so can't xvid's decoder handle it?
It's been encoded with libavcodec, using "simple" DCT. Using ffdshow with Decoder options->IDCT set to auto or simpleMMX/simple should work.

[cayblood]

It's been encoded with libavcodec, using "simple" DCT. Using ffdshow with Decoder options->IDCT set to auto or simpleMMX/simple should work.

squid_80, how can I find out what type of ffdshow decoder I need set for a given avi file? I can't always see these details in the file properties.

THanks,
Carl