Why doesn't separate fields and double weave remove interlacing artefacts?

[mgh]

I have tried PAL as well as NTSC DVDs. The mice teeth effect does not go:confused:
Or am I doing something wrong
e.g.
directshowsource("C:\video_ts\vts_01_1.vob")
separatefields()
doubleweave()
does not remove the mice teeth -i mean short horizontal lines in movement regions.

[kingmob]

Why do you think this should remove them?
Unless i'm very much mistaken, doubleweave() could even create the miceteeth, if your source was progressive.
If you want a 50fps or 60fps video as a result, use bob() instead.

[Si]

Fomr the docs

DoubleWeave... it combines fields 0 and 1 into frame 0, fields 1 and 2 into frame 1, and so on.

I've never used it but I think its designed to give you a set of frames made up something like (but probably not quite) - the docs aren't clear about using SepFields first :confused:

F1 F2 F3
F2 F3 F4

so if F2 and F3 or F3/F4 are from different moments in time (quite possible with NTSC films) then they will have "mice teeth" on those frames.

There are about 100 ways to restore progressive frames around here but I don't think this is one of them :)


regards

Simon

[mgh]

same problem with bob in addition the video bobs up and down:)
My thinking was the script separates frieldss so no interlacing problem at penalty of double the no of frames

[Guest]

You can get that effect and keep the original rate by just discarding a field and resizing:

separatefields
selecteven
lanczosresize(back to original size)

You can do the same with dumb bobbing, which would give you double the frame rate. Done correctly, the video will not jump up and down.

But adaptive deinterlacers are usually preferred, because they deinterlace only the parts that need deinterlacing, keeping full resolution where possible.

[stickboy]

Originally posted by Si
I've never used it but I think its designed to give you a set of frames made up something like (but probably not quite) - the docs aren't clear about using SepFields first :confused:They seem clear to me:If the input clip is frame-based, this filter acts just as though you'd separated it into fields with SeparateFields first.
Originally posted by mgh
My thinking was the script separates frieldss so no interlacing problem at penalty of double the no of framesIt separate fields, but it also combines them back together.

[Si]

@stickboy
Like I said- I've never used it.

Does it do a sepfields and then the f1f2 f2f3 f3f4 combining business if Avisynth things its frame based but just the f1f2 f2f3 f3f4 combining business if Avisynth thinks its field-based?

If so, then the docs are clear - its just the filter thats funny :)

It's one of Ben's orignal explanations that I've just ignored because I never needed to understand/challenge it. :)

Either way its not the way to go for mgh :)

regards

Simon

[Wilbert]

Does it do a sepfields and then the f1f2 f2f3 f3f4 combining business if Avisynth things its frame based but just the f1f2 f2f3 f3f4 combining business if Avisynth thinks its field-based?
Yup.

You can use it (ie DoubleWeave.SelectOdd) to change the field dominance:

http://forum.doom9.org/showthread.php?s=&postid=410692#post410692

[Mug Funky]

1. use DGmpegdec to decode your vobs.

2. interlacing is NOT an artefact! i don't know where this piece of misinformation comes from, but it drives me insane because people are deinterlacing video and thinking they're improving it! unless you want "film look" or need very low bitrates, leave the video as it is! ffdshow will bob on playback, as will a host of other playback filters and decoders out there. every new video card supports hardware accelerated bobbing (and a lot of the old ones do too) which will mean you never see combing, keep the original motion, and don't lose any information.

k, that probably sounds a little harsh, but it's nothing personal.

if your source is film, then IVTC it rather than deinterlacing it. if it's not IVTC'able, then encode it interlaced (Xvid does this pretty well, and the newer MPEG-2 codecs like QuEnc and HC handle it brilliantly if you can spare the bitrate).

examples of stuff that can't be IVTC'd are field-blended anime (hehe... nobody hit me, but i do this for a living now - running NTSC anime masters through a blendbox), oldschool telecined films (older telecine machines would give top-to-bottom blended fields. you'll probably only see this on VHS tapes), and stuff that was telecined so badly that it's pattern changes constantly and any IVTC filter will not know what to do with it (examples - simpsons episodes, Evangelion from the old masters, and a few other animes that were telecined on the cheap).

with the sophistication of current IVTC plugins (TFM, bruteIVTC, smartdecimate, even Tdeint will do a good job), the only stuff that can't have progressive frames recovered adequately are the field-blends.

[mgh]

I want to convert format for playback on my PC. I know it is not a defect in the video. Saw somewhere-that above was the "perfect way of elimination of problem" at penalty of doubling fps.
Seperatefields alone works-with half height of video anf double fps.
Other than blend fields of Virtualdub and equivalent in avisynth- no other filter seems to remove all traces of interlacing-but also there is some amount of blurring. So thought of trying it out.
Thanx for all the inputs.:)

[Mug Funky]

you could set "interlace" with your encode, then use ffdshow and your video card to bob it on playback - that's basically how software DVD players do it. you wont have to see the interlace unless you open it in virtualdub, or something that's not interlace aware.