Deinterlacing

[dead_pyhto]

Maybe I'm missing some principles of deinterlacing so, please, tell me (link to explanation may be very useful)

The preview in DVD2AVI says that the source is Pal, 25fps, interlaced, but it looks like deinterlacing is needed.

I thought that IVTC is useless but tried it - no result.
Deinterlacing tool of the codec (DivX 5.01) seems to work (I set "All the frames are interlaced") but I would like to know if there is more efficient and quicker filter for VirtualDub or other way to deal with it, isn't it?

[jggimi]

IVTC = "InVerse TeleCine" ... it has nothing to do with interlacing.

Vdub has one built-in de-interlace filter.

If you use AviSynth with Vdub, there are these built-in de-interlace methods:

SmartDeinterlace
VerticalReduceBy2 - Gknot calls this "Fast Deinterlace"

You may also be able to use the GreedyHMA filter.

Another AviSynth filter pack that includes a variety of de-interlacing and IVTC capabilites is DeComb.

[avih]

>"The preview in DVD2AVI says that the source is Pal, 25fps, interlaced, but it looks like deinterlacing is needed. "

:) correct, correct. that's the whole point.

it's interlaced, that's why there are these 'artifacts', and that's why it may need deinterlacing.

note, however, that in most dvd films, it's not 'real' interlaced, just pal telecined. (i.e. the source was 24fps progressive, transformed to pal 25fps interlaced to store on the dvd). from this kind of source, you can fully recover the original frames without loss of information.

so if it's only telecined, you should use some inverse telecine. and if it's 'real' interlaced, you should try one of the jggimi's filters

[dead_pyhto]

Thanks, guys!

Now I have much work: reading the Decomb guide, writing scripts...
Thank you for giving me more information and suggesting alternative ways - that's what I had been looking for.

[ChAoS Overlord]

Originally posted by avih
note, however, that in most dvd films, it's not 'real' interlaced, just pal telecined. (i.e. the source was 24fps progressive, transformed to pal 25fps interlaced to store on the dvd). from this kind of source, you can fully recover the original frames without loss of information.

Hmm I'm curious:
a) how do you see wether this is the case?
b) what is the way to recover it?

[jggimi]

Hakko's comments (3rd post down) may help: http://forum.doom9.org/showthread.php?s=&threadid=23776

[ChAoS Overlord]

Yes ok, but I still don't know when something that is PAL 25 fps originated from a progressive 24 fps source and how to get back to it... Normally I just deinterlace on my interlaced PAL's.

[temporance]

Originally posted by ChAoS Overlord
Yes ok, but I still don't know when something that is PAL 25 fps originated from a progressive 24 fps source and how to get back to it... Normally I just deinterlace on my interlaced PAL's.
If your PAL source originated at 24fps and was produced in a professional environment, there will be no telecine. To convert movies for 25fps PAL, the film is simple run 4% faster. The audio is also speeded up by 4%.

IMHO, there's no point trying to get it back to the original 24fps.