Newbie seeking help about deinterlacting/IVTC

[AtomicShroom]

Hello all. This is my first post, so please be kind.

I'm trying to encode DivX movies of my ReBoot DVDs. I downloaded GKnot and encoded a few DivX movies already, but so far it's been rather simple since everything was FILM.

Now those ReBoot DVDs are different. DVD2AVI reports over 95% NTSC, Interlaced picture. Analyzing the frames, I'm led to believe (from reading FAQs on this site), that it's been Telecined. In GKnot, I selected IVTC, however the final result had a rather jerky playback. I also tried Kernel Deinterlacing and Field Deinterlacing, but both had "artifacts" that really bugged me. Kernel Deinterlacing leaves somewhat of a blue ghost behind things as they move, and Field Deinterlacing produces a weird motion blur that is rather annoying.

I've seen that there are other IVTC methods, which might be more advanced. The page recommends trying TMPG. I tried opening my DVD2AVI project file as stated, and it wouldn't recognize it as something it can open...

So I'm kinda getting desperate about trying 85374 different options that might not work, when someone here could probably tell me in about one minute the right way to do this.

So can anyone help?

Thanks muchly.

[nFury8]

Hi there.
I'll give it a shot. I'm assuming that your source is really telecined. And since you're using Gknot, that would most assuredly mean you're encoding the Virtualdub/VirtualdubMod way. One approach you could tackle is to tweak the Decomb (I'd say the most popular IVTC app out there) settings, Decomb has a very thorough documentation explaining each parameter. You can tweak these settings via your .avs script generated by Gknot. I suggest that when you save your project in DVD2AVI, set your 'Field Operation' to none. The other method is to just use other IVTC app like SmartDecimate. Both Decomb and SmartDecimate can be found in the Avisynth section of this forum. If this isn't clear enough just shout for help again.

[Guest]

To avoid motion blur with FieldDeinterlace() set blend=false.

We can't tell you how to treat the video without seeing a sample clip. That would be like asking a doctor to give you the right treatment for "my stomach hurts".

Can you make a short sample unprocessed source clip available for inspection?

[gte024h]

Great thread guys. I have a quick Decomb question as well... I have a BBC produced DVD for Region 1 and I think the source is PAL (25FPS). Just loading up the file using AviSynth without Decomb, I can see the pattern of:

IIIIIP-IIIIIP-IIIIIP... (I=Interlaced, P=Progressive) with 29.970 FPS.

I tried Decomb's Telecide function using guide=0 through guide=3 and none of them seemed to be able to "lock" onto the pattern (order is set properly too). The pattern is very predictable, particularly in panning scenes so I would expect Decomb511.dll to have no trouble. I have used Decomb in the past for regular IVTC 24->30FPS stuff with great success, but I haven't been able to do anything with my BBC DVD's. Am I out of luck, or is there some other setting for patterns like this?

[nFury8]

@gte024h:
You said your source is PAL (25fps), why do you want to IVTC it? If it is interlaced then just do a deinterlace.

[gte024h]

Sorry about the confusion, the original source was probably PAL since it was produced in the UK, but the Region 1 DVD released in the US is NTSC, so they obviously telecined the PAL to NTSC (25->30 FPS). I just want to undo that so I can get back to the original 25 FPS progressive stream.

[nFury8]

Oh, ok. Alrighty then. In that case, our main man neuron2 should be the most qualified to shed light on your problem. I think I'd be adding just more confusion if I continue to open my virtual mouth, heheh. Mainly because I've never done a 24->30FPS stunt before like what you are trying to achieve.

[manono]

Hi-

I've done tons of them. As you say, it's on the NTSC DVD at 25fps (actually 24.975fps). You have 2 choices. Use Telecide with Decimate(6). That should give you reasonably smooth playing with tons of blurred/blended frames. Or you can use the RePAL filter. That will remove most of the blends. Search the AviSynth Forum for information on the RePAL filter. If you have any more problems/questions, then come on back here.

Actually, you also have a third choice, scharfis_brain's UnblendPattern. With luck, you can remove all the blends and get it to play perfectly smoothly. But the learning curve on that one is fairly steep, and will require hours of set-up work. It depends on how much you like the movie. I'd recommend RePAL. It's slow, but fairly reliable and easy to learn.