Deinterlacing Question

[jagabo]

Yes, it's 25 fps progressive PAL with 3:2:3:2:2 pulldown. Use TDecimate(mode=2, rate=25) to restore it to progressive frames.

[hizzy7]

Yes, it's 25 fps progressive PAL with 3:2:3:2:2 pulldown. Use TDecimate(mode=2, rate=25) to restore it to progressive frames.

If I can ask, how did you figure this one out? What should I be looking for?


Thanks!

[jagabo]

After TFM() every 6th frame is a duplicate. That indicates 25 fps was converted to 30 fps. I just assume the missing field every 500 frames to make up the difference between 29.97 fps and 30 fps.

[manono]

That indicates 25 fps was converted to 30 fps. I just assume the missing field every 500 frames to make up the difference between 29.97 fps and 30 fps.

There's a problem there, though, and that is TDecimate reads ahead by only 100 frames. This will lead to more mistakes than it might even if you did put on the 'M2PA=True' parameter. Quoting from the TDecimate doc:

m2PA -

Will override the default read-ahead maximum of 100 for mode 2. This will allow the
one pass mode (metrics not available from an input file) to produce the same results
as if the metrics were available.

**NOTE: the cycle size could very well be in the 1000's or 10000's, so there is the
possibility setting m2PA=true could mean the processing will stall for quite
some time (5-10 minutes or more) when a new cycle starts!!! Please check the
largest cycle size that will be used using debug=true before setting m2PA=true!

true = override the default maximum
false = don't

Default: false (bool)

In addition, in many, if not most, cases it really is supposed to be 24.975fps. Forcing a frame decimation every 6 frames will lead to fewer mistakes than allowing the decision to remove 167 frames in every 1000. Therefore, in the absence of evidence it really is supposed to be 25fps, I make it 24.975fps by doing this:

TFM
TDecimate(Mode=0,Cycle=6,CycleR=1)

Then it (or 25fps) can either be encoded as-is or (preferable, in my mind), slow both the audio and video to film speed. For changing the video speed you add:

AssumeFPS(23.976)

to the script. And slow the audio to match. Of course, a case can be made that having an extra duplicate frame every 40 seconds (when encoding for 25fps when it's supposed to really be 24.975) is better than losing a unique frame every 40 seconds (when encoding at 24.975fps when it's supposed to be 25fps), but in my experience the majority of the movies I've studied (most of them field-blended) really are 24.975fps. Not all, though.

That's such a crappy-looking video, and there's so much more wrong with it over and above any decision to make it 24.975fps or 25fps.

[hizzy7]

Hi!

When using TDecimate(mode=2, rate=25) I would get this error upon the film's completion:

TDecimate: mode 2 internal error (ret less than 0). Please report this to tritical ASAP!

Would that have to do with the 25fps vs 24.97?

Thank you again for your help, both jagabo and manono!

[jagabo]

When using TDecimate(mode=2, rate=25) I would get this error upon the film's completion:

TDecimate: mode 2 internal error (ret less than 0). Please report this to tritical ASAP!

Would that have to do with the 25fps vs 24.97?

I don't think so. Never seen that error. Using TDecimate(cycle=6, cycler=1) might be a way to work around the problem though.

[hizzy7]

What is funny is the outputted file played fine, despite the error!

[hizzy7]

Hi Folks,

Back with another one:


http://files.videohelp.com/u/183506/atermin.demuxed.m2v


Is it possible to save this one? There's some weird blurring going on. Would that be from a poor PAL/NTSC conversion?


Thanks again, Video Jedi of Videohelp!!!

[manono]

It was telecined and then blend deinterlaced. 2 of every 5 frames are blended. It's native NTSC and not PAL2NTSC. There are a couple of AviSynth filters that are supposed to be able handle this kind of thing but I couldn't get either of them to work well. Maybe someone else can provide more help.

[jagabo]

FixBlendIVTC().TDecimate().
http://avisynth.org/mediawiki/FixBlendIVTC

[manono]

That's odd. I tried both FixBlendIVTC and Srestore(omode=3) and neither worked for me. Must have done something wrong. Yours looks good, the way it's supposed to.

[hizzy7]

Thank's guys!! If I can ask, what was the visual indication that it was blend de-interlaced. I hope that one day I will be able to figure this stuff out on my own! Thank you again!!!!!!!

[jagabo]

That's odd. I tried both FixBlendIVTC and Srestore(omode=3) and neither worked for me. Must have done something wrong. Yours looks good, the way it's supposed to.

All I did was:

Mpeg2Source("atermin.demuxed.d2v", CPU=2, Info=3) 
FixBlendIVTC()
TDecimate()

Thank's guys!! If I can ask, what was the visual indication that it was blend de-interlaced.

When you step through a sequence with motion you see a pattern of 3 clear frames and 2 frames that look like double exposures, repeating over and over.

[hizzy7]

Great! My only issue is that is looks to have changed the size of the image on me. It was wide, but now it's kind of "squashed". How did you avoid that?

Thank you!

[jagabo]

The video is 720x480 16:9 DAR (32:27 SAR). I encoded that way as h.264 in MKV. If your not getting 16:9 DAR when playing my sample video you're player isn't obeying the AR flags. If you're encoding you own videos you must tell your encoder that the source is 16:9 DAR or 32:27 SAR. Otherwise it may assume 3:2 DAR.

[hizzy7]

The video is 720x480 16:9 DAR (32:27 SAR). I encoded that way as h.264 in MKV. If your not getting 16:9 DAR when playing my sample video you're player isn't obeying the AR flags. If you're encoding you own videos you must tell your encoder that the source is 16:9 DAR or 32:27 SAR. Otherwise it may assume 3:2 DAR.

Hi Jagabo!


Yours plays fine, but when I encode mine into lagarith with avisynth, it's coming out squished. To be more specific, when I load it into premiere, it is squished, but when I tell the encoder that it should be 16:9 dar, it's fine. first time i have seen this.


Thanks,


h

[hizzy7]

Hi Folks!

I have another one here that I think is beyond repair, but I hope I am wrong. Is it possible to get the the ghosting/blurring out of the picture? Here is the link: see post below, please

Thanks again!!!!

[hizzy7]

See post below, please

[manono]

It's the same one as before. At least for me it is, that cop shootout.

Edit: Still the same.

[hizzy7]

This is it!! Sorry! http://files.videohelp.com/u/183506/VTS_01_1.demuxed.m2v

[manono]

It's field-blended from an NTSC source (a VHS tape, it looks to me). Handle it like this:

Yadif(Mode=1)#or the better QTGMC
Srestore(Frate=23.976)

[hizzy7]

Thanks Manono! Would you also use TFM() in the script, or is it not called for? Thanks!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!

[jagabo]

To use SRestore() effectively you need the double frame rate provided by Yadif(mode=1). TFM() doesn't have a double frame rate mode.

But I'm still seeing lots of blending after Yadif(mode=1).SRestore(frate=23.976).

[hizzy7]

Yes, I have noticed the same. It is better, though. I am using QTGMC. Do you have any suggestions for the blending, Jagabo?

[jagabo]

Do you have any suggestions for the blending, Jagabo?

No. It looks to me like someone applied a very heavy temporal filter in addition to the field blended frame rate conversion. Or maybe it's been through two field blended frame rate conversions. Some fields are a blend of 3 film frames.

[hizzy7]

I am curious, what is a temporal filter? Do they exist in avisynth?

[jagabo]

A temporal filter averages together pixels from several frames (or fields) in order to reduce noise. There are many in AviSynth, McTemporalDenoise, TemporalDegrain, fft3d, TTempSmooth, etc.

[manono]

Or maybe it's been through two field blended frame rate conversions.

That's the impression I got, too - double-blended. Maybe it was blended from a film source originally, to get to PAL, before then being field-blended to go back to NTSC. But it didn't seem to affect the unblending to get back to PAL from what he has. And I don't believe there's any way to clean up the rest. Unfortunately, hizzy comes across all kinds of lousy DVDs.

[hizzy7]

This is a super stupid question, but I was wondering - can I run my file through avisynth twice to get rid of double blending?

[jagabo]

This is a super stupid question, but I was wondering - can I run my file through avisynth twice to get rid of double blending?

Not really. The way SRestore works is by picking frames (previously fields) with no (or the least) blending artifacts. The only way you could get a video with less blending artifacts is to reduce the frame rate further. You'd be left with a very jerky video.