Cannot Understand This...

[EpheMeroN]

I have an NTSC DVD that, when previewed from a D2V file in Vdub frame by frame, has a perfect 3-2 pattern of 3 progressive, 2 interlaced. Yet when I use this script below:

LoadPlugin("C:\Video Related\AviSynth v2.5.5\Plugins\DGDecode.dll")
LoadPlugin("C:\Video Related\AviSynth v2.5.5\Plugins\decomb521.dll")
MPEG2Source("F:\Test.d2v", cpu=4)
Telecide(order=0,guide=1,post=2)
Decimate()
Undot()

...I still get weird artifacts in the image. Below is an example. Look at the bottom left corner and also around the left part of the guy's head:
http://img100.exs.cx/img100/8519/fff.png

What is causing this? Even if I run KernelDeint() through the video it still occurs and creates jaggies throughout the entire film. I can post a VOB sample if needed.

[AS]

I take a gamble and say that's the chroma bug.

Try mergechroma(tomsmocomp(-1,5,0)) after decimate().

Also if you have a good pattern of 3-2, you should really use post=1 (or may be even 0 if you don't need hints) for telecide().

[Dreassica]

And since you use postprocessing on interlaced material, you would be better off adding iPP=true in the mpeg2source line as well.

[stickboy]

If the telecine pattern is perfect throughout, you can use my JDL_IVTCPattern (http://www.avisynth.org/stickboy/) function.

You also can use JDL_UnfoldFieldsVertical and/or JDL_SplitYUV to see if it's a chroma problem.

[scharfis_brain]

there are much DVDs out there sampled with wrong chroma.

[EpheMeroN]

Adding "ipp=true" fixed it. What a simple fix hehe.

Try mergechroma(tomsmocomp(-1,5,0)) after decimate().

I don't quiet get that method. I thought tomsmocomp was a deinterlacer?

[Mug Funky]

it will deinterlace the chroma. YV12 sampling means interlacing in chroma shows as "double-height" interlace (those artefacts you saw). tomsmocomp on the chroma will get rid of them.

but if IPP solved the problem, dont go so far as deinterlacing chroma, as you'll lose a little chroma detail (not that it usually matters).

[kingmob]

Can someone tell me what that iPP=true line actually does? Or get me a link to an explanation ofcourse ;).

[Boulder]

My guess is that it separates the fields and processes them individually. With ipp=false it just processes the whole frame.

[Mug Funky]

yep, that's it.

ipp = interlaced post-processing.

[kingmob]

Ok thx. Figured it would become handy one day for me :).

[EpheMeroN]

And since you use postprocessing on interlaced material, you would be better off adding iPP=true in the mpeg2source line as well.

Well adding ipp=true totally fixed it as I posted above but this other question has been nagging at me all night now.

All dvd's are essentially interlaced yes? So wouldn't we always want ipp=true in the script? Granted Telecide and Decimate bring it back to its original FILM state, but only AFTER you have decoded the video into your AviSynth script.

So how come this is the first time I've noticed this chroma error? Is it just due to a bad dvd transfer?

[stickboy]

Originally posted by EpheMeroN
All dvd's are essentially interlaced yes?No.