IVTC and forced film on 29.97 fps

[erci]

I have a little question regarding IVTC and Forced Film. I know when I need to activate forced film on an 29.97fps source, and reading the guides I know when I shouldn't. Though something that I don't find completly clear is, if the source is not Film or Film 95%> that would make it Film %-94% or NTSC do I ALWAYS need to enable IVTC to correct the frame count?

[kotrtim]

if the source is not Film or Film 95%>
Is it 95% < ?

that would make it Film %-94% or NTSC do I ALWAYS need to enable IVTC to correct the frame count

I'm stuck here..

I'll try to answer, if it's < 95% or NTSC, disable force film, step 2, checking it by browsing frame by frame, if you see there's mixture of progressive frames and interlaced frames, that means it is still a 23.976 content, but you'll need a more advanced filter such as decomb

[erci]

so I browse frame by frame... see if there is any "bad" frames and if there is I can avtivate the inverse telecine option in gordian knot since that is what I am using?

[foxyshadis]

If the film percentage is very low, like 90% or less, you'd probably be better off using a hybrid IVTC like TIVTC or decomb's hybrid mode. If it happens only on intro and outro credits (the usual case with film 90-99%) you can probably get away with ignoring them and ivtc'ing the whole thing.

For more information on handling hybrid video:
http://www.avisynth.org/VariableframeRateVideo

[erci]

and if the source is NTSC instead of film?

[Lyle_JP]

and if the source is NTSC instead of film?

Are you asking "What if the source is true interlaced video"? Then encode interlaced. Sure, you could try to line-double it with some motion-adaptive filter, but it may create more visual unpleasantness than you'd like.

[erci]

I don't know if that is true interlaced I assume it is. It says that video type is NTSC and that frame type is interlaced.

[kotrtim]

sometimes, NTSC interlaced is not really interlaced
it is 3 frames progressive, 2 frames interlaced, 3 p, 2i,......
The movie is originally 23.976 and is converted to 29.970

For safety reasons, check frame by frame randomly throughout the movie to check for such patterns, umh, you can do this frame browsing with DGIndex, it is somewhere in Gordian Knot's shortcut folder in start menu. if you these patterns, you use decomb

If you see 100% interlaced frame, use deinterlacer

[foxyshadis]

Or you can use megui's one-click mode source detection, it'll tell you if it's progressive, telecine, hybrid, video, or random static, and give you a basic avisynth script to fix it. :p

[Elic]

erci
> It says that video type is NTSC and that frame type is interlaced.
Try to add avisynth's filter called doubleweave() and check frame-by-frame, and if you find at least 4 non-interlaced frames in group of 10 consecutive frames then it is IVTC'ed film (maybe non-standard), then you may add pulldown() filter after doubleweave() and find its parameters manually (see avisynth docs about these filters).

Or, you may see only 2 of 10 frames is non-interlaced; it means that DVD is made from film by other means than standard telecine, and I don't still know how to repair that... :(

[erci]

is that when every fifth frame almost is frozen, it looks duplicated.

[foxyshadis]

Add decimate to remove the duplicates. (If it's a constant pattern.)

[Elic]

erci
> every fifth frame [...] duplicated.
Clarify please: is it after insertion of doubleweave() or in original video? If in original, foxyshadis is right; if after doubleweave() - try pulldown().

[erci]

Add decimate to remove the duplicates. (If it's a constant pattern.)

so what is decimate, and how does it work?

[laserfan]

erci I have a similar (identical?) problem to your own, whereby AutoGK makes files where the 5th frame is a dupe of the 4th. Not sure (yet) how the mistake is made in the first place, nor how to fix a file that's been made in this manner. Take a look here. (http://forum.doom9.org/showthread.php?t=107210)

So I'd like to know how Decimate might be used to remove the extra frames also.

[erci]

Where can I find decimate, because it is not a standard filter for avisynth as I can see at least. Also since I know that it is every fifth frame throughout the whole movie how do I set it to remove that fifth frame and does that filter make sure that the audio stays the same?

[foxyshadis]

Decimate is part of Decomb (http://neuron2.net/decomb/decombnew.html), and that's exactly what its main purpose is. (Taking into account elic's comment.)

[erci]

THank you guys this seems to be working fine