Processing Interlaced Source as Progressive

[vigi_lante]

Hi, :)

Before someone ask :D, yes, I'm talking about a interlaced source, since I'm capturing NTSC cartoons directly from my cable tv. But I don't know if it's true interlaced or not... :confused:

What I'm trying to do is avoid, at any costs, the shimmering around the edges from the encode. It's always something very anoying to me. :scared:

I tried all kinds of Decomb configurations, but I heard that deinterlace is not perfect. So, I decided not to use it. ;)

I'm processing the video like I did before, only without Telecide...

LoadPlugin("xxx")
Avisource("d:\xxx.avi").ConvertToYV12()
Decimate()
Spatial_Filter()
Temporal_Filter()
Spatial_Filter()
LanczosResize(480,360)
Limiter()
ColorYUV(levels="PC->TV")

I was expecting to see that "interlaced effect" on moving parts. But when I resize the source to 480x360 (the source is 720x480), playing the video, it's not really possible to see this effect. It's there. But it's possible to see only looking frame by frame on VirtualDub.

However, if I don't resize and keep the 720x480, the effect is very visible.

So, my question is: is there any real bad effect to "deinterlace" using this method instead of the real deinterlace (using Telecide) ? If no, this is the correct way to do this ? :eek:

Another question...

What kind of filter or method I could use to reduce (or maybe eliminate) the shimmering around the edges ? Anything. What kind of resize is better for this task (LanczosResize or Bicubic), and so on...anything. :devil:

Thanks! :)

[Guest]

>But I don't know if it's true interlaced or not...

You can't make processing decisions without knowing the nature of your source material! You're just groping in the dark.

Your post shows several misconceptions also.

I suggest that you post a link to a small *unprocessed* source clip for us to inspect. We'll then tell you how it should be processed and how we arrived at the conclusion. You'll learn a lot from it.

[vigi_lante]

Well, let me know if this raw sample is good enough...

http://geocities.yahoo.com.br/vigi_lante/mjpeg.avi

5mb

[vigi_lante]

I'm following Decomb manual, but I'm still trying to set the correct Post Processing value... :confused:

Take a look...

So, what Telecide does is take this frame, that is called interlaced...

Pic1 (http://vigi_lante.tripod.com.br/1.jpg)
(maybe you need to copy and paste into the broswer)

...and transform into a progressive frame, that don't have this comb effect.

The manual say that I need to use this script...

AviSource("d:\box\caverna.avi")
Telecide(order=1,guide=1,post=3,vthresh=30,show=true)

...to set the correct post processing value.

What I need to do is find a correct value that will tell decomb: "you need to deinterlace frame 1361, but not 1362". Is that right ?

Now, take a look at this picture...

Pic2 (http://vigi_lante.tripod.com.br/2.jpg)
(maybe you need to copy and paste into the broswer)

When there is a interlaced frame, I always get high values (100+) in the second vmetric number, and on this frame, the value is "144". Is there any way to configure decomb to deinterlace only the frames that have high values (more than 100) on this second vmetric field ?

Because, from what I read on the manual, I need to find a vthresh value that will limit the range of the deinterlace based on the chosen vmetric value...

Example...

My vthresh is: 60

So, decomb will only deinterlace frames that have a chosen vmetric value that is 60 or more. Is that right ?

But the problem is that I have a lot of interlaced and progressive frames that are inside this range. So, how I would solve this problem ? :scared:

Thanks in advance!

[Guest]

Downloading...please standby.

[Guest]

Next time I'll remember to say a short clip!

You gave me 1500 frames of highly compressed Xvid. Can you give me just a couple hundred frames in HUFYUV? I don't care how big the file is. Pick a section that you are having problems with.

I assume that isn't your source clip and you compressed it for upload. Is that right? What is the source material? If it is a VOB you can cut a VOB fragment.

[vigi_lante]

Sorry, my source is HUFYUV, I will do that right now...

Thanks.

[vigi_lante]

Done...

Since I have only 15mb of host space. I compressed with mjpeg, but now it will do the job...

http://geocities.yahoo.com.br/vigi_lante/mjpeg.avi

[Guest]

The link is dead. Did you type the URLs correctly?

EDIT: OK, got it. Geocities throttling, eh?

[Guest]

I processed the clip with this:

loadplugin("d:\don\programming\c++\avisynth\decomb\release\decomb.dll")
avisource("mjpeg.avi")
crop(0,4,-0,-0)
telecide(order=1,post=2,guide=1,vthresh=75)
decimate()

The results were fine.

If you are asking how to set a perfect vthresh, it can't be done. But it is better to catch a few progressives than to let combs through, so err on the side of caution.

Really picky people err on the high side and then use overrides to force the stray combs to be deinterlaced.

EDIT: I see dot crawl. Are you are using an S-Video connection and not composite?

[vigi_lante]

But this clip don't have any interlaced frame with this vthresh range(75), so all interlaced frames will not be deinterlaced. That is the idea ?

[Guest]

This is 3:2 pulldown material, so Telecide matches the fields and produces progressive frames. You don't want to deinterlace those good progressive frames. But for various reasons, sometimes combed frames slip through the field matching and you want just those to be deinterlaced. In the clip you provided there were no stray combs so no deinterlacing had to be done.

There is a big difference between real pure interlaced material and 3:2 pulldown material. There is a very good sticky thread in the DVD2AVI forum about this. Check it out.

[vigi_lante]

Oh brother, nothing makes sense...

I will try to find a newbie explanation to understand all this mess...until there, I will trust in your word.

Thanks for the help.

PS: Do you know which resizer avoid more shimmering around the edges: LanczosResize or BicubicResize ?

[Guest]

The edge noise is dot crawl. What kind of cable are you using to connect your signal to the capture card?

Oh, here's a good newbie resource: http://www.100fps.com

[vigi_lante]

Normal TV Cable, coming from the street.

[Guest]

That's your problem right there. You should look on the back of your cable box and find an S-Video output. Connect that to the capture card, assuming it has an S-Video input. If not, get a better one.

EDIT: Judging by the noisy signal you probably have analog cable and no cable box, in which case you are screwed. Your capture card has a crappy comb filter. Try the Capture forum. :)

[vigi_lante]

Yep. It's a RF analog cable coming directly from the street, without cable box. There is no way that I could use S-Video or something else.

But it's possible, at least, to reduce this dot crawl using filters, isn't ?

[Guest]

Originally posted by vigi_lante
Yep. It's a RF analog cable coming directly from the street, without cable box. There is no way that I could use S-Video or something else.

But it's possible, at least, to reduce this dot crawl using filters, isn't ? Search for "rainbows" and "dot crawl". There are attempts at it, but don't get your hopes up. Can't you get digital cable?

[vigi_lante]

Since a do a lot of caps, this cable is the most fexible option to schedule all the captures. With a digital cable, I would need to manually turn on the decoder, change the channel etc

[Wilbert]

Have a look in the cap guide. However, it's only possible to remove those in static scenes with avs.

Since you are a NTSC guy, you can try

http://home.earthlink.net/~tacosalad/video/dotcrawl.html

It's a vdub filter, but it also removes dot crawls and rainbows from dynamic scenes.

[vigi_lante]

Is there any other filter like this one for AVISynth ? Because I use Fast Recompress on VirtualDub, so I can't use any Vdub filter. I guess that there is one Avisynth filter called Undot, don't know if it have the same function, but I will try to test...

[trevlac]

@vigi_lante


Did you try that vdub filter and just see what you get? The theory on that page seems great. I was wondering what happens with a real NTSC case. I tried your sample, but it is hard to tell on a small clip. The filter seems to smooth things out quite a bit. Maybe too much.

You can probably use the filter in AVS if you are willing to do a colorspace conversion.