combing effect!!!!!

[cjaar]

hi all...

How can i avoid combing effect(similar to combs theeth on the edges of fast moving object). in dvd2avi preview window it shouw as 4:3, NTSC, 29fps and Interlaced. I hv checked field operation to NONE. As per the DOOMs guide..

****************
Frame Rate = 29.970 fps: Let the preview run for a couple of minutes, then take a look at the Video Type: If it's FILM at a percentage higher or equal to 95% you can activate Forced FILM as shown below. IF it only shows FILM the same applies.
>>>>>Otherwise you will have to perform IVTC, the same also applies if the Video Type is NTSC.<<<<<<

*****************
As per the above lines, video type is NTSC, i hv to check IVTC. This is in the encode window, as i check ivtc and start encoding... Gnot hangs... What could be the problem. Hv i missed something here????

I even tried force film... and still the same effect. What about the options smart/fast dinetrlace and inverse telecine

plz... help me.

TA
cj:confused:

[ookzDVD]

I assume your source is NTSC-Interlaced,

So the easy thing is just use SmartDeinterlace,
but if you sure that the movie was telecined,
better use decomb to IVTC it.

PS. set the force FILM to Off.

[jggimi]

Don't Panic.

First, you need to understand that DVD's can be created from different types of sources. DVD's can be transfers from film, transfers from video, or a combination of the two. OK?

Second, you also need to know a little bit about two terms:
Interlace
Telecine
They are not the same.

Interlaced video -- which is what your source is -- needs to be de-interlaced before you do anything else to it. That's because an interlaced signal contains 2 half-frames that get -- interlaced -- to create a single image. First comes the odd lines, then the even ... or sometimes it's the other way around. OK?

Telecined video -- is a video transfer made from 35mm film running at 24 frames per second. The process converts to 30fps by duplicating 6 of those 24 frames. To get back to 24fps, a process called IVTC, or Inverse Telecine, is used to remove those duplicate frames. Now, it's not exactly 30fps, it's 29.97. So the IVTC step, when used, brings the frame rate to 23.976. Still with me?

---

In the Gordian Knot encoding suite, there are two built-in de-interlacing tools. One is called Fast Deinterlace, the other is called Smart Deinterlace. If needed, there is also a Swap Field Order option in dvd2avi, for use when the interlaced video is the "even before odd" instead of "odd before even" as I described above.

Also in the suite, there is one built-in IVTC tool. It's the Force FILM option in dvd2avi. If the Telecine process used was non-standard, you must edit the avs file manually, to use an IVTC filter, also you must manually change the framerate in Gordian Knot.

In addition, there is an add-on toolset for AviSynth that gets rave reviews. It contains both de-interlacing and IVTC filters, and while the included documentation is very good, Doom9 just published a very nice guide on using it. It is called, you might be interested to know ... DeComb.

You have not yet seen everything available to help you with this on Doom9's web site. There are some Guides that are more general, and the FAQs are excellent, too. I recommend a great doc you can find there called "Telecine Explained."

Lastly, there's a thread I found in one of the Forums recently that can shed a great deal of light on the steps you might need to take, how to use the filters without error, etc. It was in the General Discussion section so you might have missed it:

http://forum.doom9.org/showthread.php?s=&threadid=22744.

I think it's the most useful thread I've ever seen here at Doom9's forum. I hope you find it as helpful as I have.

[cjaar]

@ookvDVD...

On the DVD cover ist NTSC.
Yes... as shown by DVD2avi is 4:3,NTSC(29fps),Interlaced. Based on this as u suggestion to use "Smart dinterlace" option, but dooms guide
*****************
1. If DVD2AVI showed your source as interlaced PAL and the preview was interlaced you enable Fast Deinterlacing here.

2. If DVD2AVI showed your source as NTSC FILM below >>95%<< you enable Inverse Telecine here and you must also change the framerate that you set in step 4.

3. In all other cases set Field Operations to None.

*****************
1,2 are not valid as my source is NTSC(29fps), in other way its 3...
so use none option... so what to use????? :confused:

Strange thing is that my mistake in set to 16.9 instead of 4:3 in resulution tab... the final avi didnt hd any such combing effect, but it was to heavy to watch it(movie size is 40% of the monitor). So wanted to encode with original 4:3.. struck with this C0mbing effect.

:confused:

@jggimi...
Before posting hd serached the forum "combing effect"... but non could help me out.:D . I understand it doesnt make sence to ask again
and agin the same problem :D

[manono]

Hi cjaar-

Although combing is a correct term, it's more commonly known as interlacing. I'll bet if you had searched for "interlacing" or "IVTC" you would have had a lot of hits.

I think jggimi's getting tired of explaining the difference between interlace and telecine, and I know I'm getting tired of explaining how to tell which kind you have. There should be a FAQ for this or it should be in Doom9's guide-no offense intended towards the fine guides here. But here goes (and this goes for only NTSC (30fps) DVDs-PAL is different):

Make your .d2v with no Field Operation (30fps). Open it in GKnot. Find a place where there's motion/action. Step through it frame by frame looking for the interlacing (combing). For every 5 frames, if you find 3 progressive frames (no interlacing) and 2 interlaced frames, then it has been telecined and you can IVTC. If you find that every frame is interlaced, then all you can do is deinterlace. You should probably try this in several different parts of the movie to make sure you don't have one of the dreaded combination types jggimi referred to.

There is an IVTC option included in GKnot, but I prefer Decomb. If you haven't had much experience with AviSynth though, you may have trouble setting it up. But Doom9 has an excellent guide for it. There are 2 deinterlacing options included in GKnot. I think the material determines which to use, but maybe encode short parts of the movies to tell which looks better to you.

To recap-if, in DVD2AVI it shows as NTSC (meaning 100% NTSC) or a high percentage of NTSC, then you can't use Force Film. You must either IVTC (and in the process bring the frame rate down to 24fps), or deinterlace (keeping 30fps). To find out which to use, run the little test I described.

At least, from now on, anyone searching for "combing", should discover this thread.

[cjaar]

hi...

thanks for all who helped me...
Smart de-inetrlace solved the combing/interlace effect.
In fact on the above smart de-interlace window, preview can be check to see any interlacing effect. May be useful for other
people like me :)

PS: when i check for IVTC option the o/p file was over sizeed(test clip was 5m27sec, size selected 32m, the final o/p was 38 mb... at the same time in logs had a warning: actual frames differ from set frames... correct new bits rate.
I assume this because of the socurce as 29fps and ivtc as 24fps... modified 29 to 24 for source and the o/p size was within 32mb
with out any sync probs... Correct me if iam wrong :D

[jggimi]

You have it right. If you're using an IVTC other than Force FILM, you must change the framerate manually to make GKnot calculate properly.

And that is GREAT advice on previewing the filter set. I keep forgetting that option exists!

[snake-boy]

Hi,

When trying to view the thread you referred to here:

------
jggimme:
"I think it's the most useful thread I've ever seen here at Doom9's forum. I hope you find it as helpful as I have."
------

I get this error message: (?)

---<snip>---
You do not have permission to access this page. This could be due to one of several reasons:
You do not have permission to access the page that you were trying to. Are you trying to edit someone else's post or trying to access administrative features? Check that you are allowed to perform this action in the Forum Rules.
If you are trying to post, the administrator may have disabled your account, or it may be awaiting activation.
---</snip>---

Anyone know what I did wrong? Or is this thread gone?

-snake

[jggimi]

The thread is gone. Not to worry. It was a short pictorial on using the Forum search facility.