"The ugly" (deinterlace/ghosting problems)

[N_F]

I recently ran into some problems while trying to encode a movie (Superman I, PAL Region 2).

It seems to be of the type hakko504 refers to as "the ugly" in the IVTC tutorial. Here's what he says:

THE UGLY: DVDS CONVERTED FROM NTSC TO PAL. These are very common among cheap DVDs. Usually they are created by blending two nearby frames into one new, in a manner that removes 1 frame in 6 (30->25fps). These look really bad and they are a PITA to work with. My solution is usually to let Telecide(post=true, blend=false) remain in the script. This will actually remove some of the worst ghosting. Then I add some form of SPATIAL smoothing. Temporal will only add to the ghosting and should be avoided at all cost in this kind of rips. If you think it looks too blurry, then try some sharpening, but be aware that this might enhance the edges of the ghost images, while at the same time remove the rest of the ghost, and you might not like the result.

I've tried just about everything in decomb I can think of without any success. It seems to be deinterlaced quite nicely (but not perfect!), but the ghosting is just ridiculous. I've tried using a spatial smoother as hakko504 recommends, but the only smoother I'm familiar with is C3D which also is temporal (which hakko504 strongly recommends against). The one I have tried is Avisynth's Spatialsoften, but there aren't any recommendations and it's damn hard finding good values when you have no idea what you're doing (should the radius be big or small for best quality for instance? I'd appreciate it if someone have some values to recommend).


NOTE: I wrote this post in notepad a few days ago (I didn't have access to internet for a few days) but I have later realised I shouldn't have to use a deinterlacer at all. The movie is in 2.35 AR, so my final vertical resolution will be less than 288 (probably 272). This should indirectly be the best possible deinterlacer, right?


You can download a short 6s clip here (it's in DivX 5.03, but ffdshow should be able to decode it) where the problem is very obvious: http://www.freewebs.com/franic/clip.avi

If any experienced users can download this clip and see if you can do anything about it I'd be very thankful.

You can work from this or create your own from scratch

avisource("clip.avi")
crop(4, 72, -6, -70)
lanczosresize(640, 272)

To sum it up:

1. I shouldn't have to use a deinterlacer since my vertical resolution is below 288, correct?

2. What can I do about the ghosting? Any spatial smoother that is considered "the best" that may do the trick?

3. Anything else you can think of.


Edit: Can you download the clip fine? I seem to be getting an extremely low speed when I try it myself.

[manono]

Sorry N_F. I'm getting less than 1000 bytes/sec, and it'll take over an hour to download.

[hakko504]

Same, here very slow speed. I'll try again tonight when I'm at home. As for spatial deinterlacers, I usually use the one included in GKnot with the same settings as GK. Note that it is a A2.07 filter. C3D can be used, but it's usually not the best solution. It's a spatio/temporal filter and those sometimes work OK on certain sources. They are not a general solution though.

Instead of telecide you can try smoothdeinterlacer. Works quite OK on some sources. And the setting for telecide should be telecide(guide=2,blend=false,post=true). Adding the guide parameter will lower the jerkiness that it can otherwise create.
@manono
Can you update this in the guide?

And the reason I'm recommending a deinterlacer is that it will interpolate one field, hopefully the field with the most ghosting thus removing ghosting. But in order to do this it must be a deinterlacer that works in interpolation mode. Use viewfields or AvsCompare to check the individual fields for blending issues.

[Guest]

You have horrible blended fields appearing in both the top and the bottom. You are screwed. Sorry.

[Sigmatador]

Originally posted by N_F THE UGLY: DVDS CONVERTED FROM NTSC TO PAL[/B]
neuron2 You have horrible blended fields appearing in both the top and the bottom. You are screwed. Sorry.[/B]

... i know this... this problem appears too times for me in PAL french DVD anime... ARRG I HATE THE MEN WHO ENCODE THESE DVD
:p

ps: rainbow artefacts over interlaced source (rainbow artefacts are'nt interlaced) are very.... "sympathique" to filter (grrrr:mad: )

:D

[N_F]

Originally posted by neuron2
You have horrible blended fields appearing in both the top and the bottom. You are screwed. Sorry.

So you downloaded it and examined it?


I'll try to throw up a better link tomorrow so that manono, hakko504 & others may try if they want.

[Guest]

Originally posted by N_F
So you downloaded it and examined it? Yes, sir.

[N_F]

If anyone's interested you can download the clip from franic.web1000.com/clip.avi.

@neuron2

Would the correct way to check this be to add separatefields() to the script? I did this last night and the single fields were indeed blended.

But a spatial smoother should still be able to get it look a little better, right?


@hakko504

But the deinterlace bit should be a moot point for me in this particular case, correct? Or could it still help remove some of the blending even though i already have an indirect deinterlacer?

[Guest]

Originally posted by N_F
Would the correct way to check this be to add separatefields() to the script? I did this last night and the single fields were indeed blended. But a spatial smoother should still be able to get it look a little better, right? Yes, of course SeparateFields() is the important tool for analysing these problems. Why do you suppose a spatial smoother can help you? I see no reason to think that.

But the deinterlace bit should be a moot point for me in this particular case, correct? Or could it still help remove some of the blending even though i already have an indirect deinterlacer? Yes, deinterlacing is moot. No, it will not provide any additional help.

[N_F]

From hakko504
Then I add some form of SPATIAL smoothing. Temporal will only add to the ghosting and should be avoided at all cost in this kind of rips. If you think it looks too blurry, then try some sharpening, but be aware that this might enhance the edges of the ghost images, while at the same time remove the rest of the ghost, and you might not like the result

Wouldn't it smooth the blending out making it less obvious? (Perhaps I should do less talking and more tests :))