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View Full Version : 29.97 to 24?

hkl8324
28th July 2006, 14:32
If that is not film material (e.g HDTV cap, TV cap, Concert DVD...)
It is stupid to change decimate the fps from 29.97 to 24 and encode?

And why?
jggimi
28th July 2006, 20:16
www.doom9.org/ivtc-tut.htm should answer your questions, even though the software it refers to is now well out-of-date.
Awatef
28th July 2006, 20:26
Fast answer: yes, it is stupid, 'cause you'll get jerky motion (there are no duplicates, so every frame you remove will cause a motion "jump").
jggimi
28th July 2006, 20:34
Caps might still be Telecined, it is worthwhile to examine a frame sequence before assuming the content was shot on video.
hkl8324
28th July 2006, 20:39
www.doom9.org/ivtc-tut.htm should answer your questions, even though the software it refers to is now well out-of-date.

Oh...I read that 3 times in the past (yes, the same page...:D) and I understand every word of it...

Still, how can I find out if my video is mixed/film/video?

(I tried deindex, it says interlaced, but putting the same video in the megui source analyser...It says it is mixed material:confused: )

Caps might still be Telecined, it is worthwhile to examine a frame sequence before assuming the content was shot on video.

How can I examine a frame sequence???
Awatef
28th July 2006, 22:04
Very easy! rely on your own analyser: your eyes!
For example, you put your avs file in VirtualDub and go frame by frame to see what you have. Jump to different places in the video to see if the result is constant. Normally, you would have an idea about suspicious places after you watched the DVD.
Like if you watch an interview of an actor, chances are big that they would throw in some sequences of his movies, and chances are even bigger that these are telecined where the interview portions are interlaced. I hope you get the idea.

By the way, if you don't know how to differenciate film and video content, chances are the biggest (:D) that you didn't understand the tutorial well.
Basically, telecined film stuff show a pattern of 3 progressive frames followed by 2 interlaced ones.
I leave the rest up to you ;)
jggimi
28th July 2006, 22:20
The tutorial has a section on doing a manual analysis. You must have missed it. Find the sequence that begins


SOME TIPS FOR MAKING SENSE OF WHAT DVD2AVI TELLS YOU

A TRULY INTERLACED SOURCE CANNOT BE IVTC’D. Unfortunately for us, DVD2AVI can not distinguish between bad telecining and genuine interlace. They will both appear in the statistics window as NTSC. One way of finding which is which is by using DVD2AVI to approximately find the NTSC parts of the film. Then use the following .avs to check the frames in Virtual Dub...
hkl8324
29th July 2006, 12:52
OK, now I am sure my video is 100% interlaced material...:D

So can I alter its fps? (decimate, because I want to save some bits from the final encode...)
hkl8324
29th July 2006, 13:06
sorry, double post...
Boulder
29th July 2006, 16:00
http://forum.doom9.org/showthread.php?t=110093
Awatef
29th July 2006, 22:40
At the risk of repeating myself: No, because you'll get jerky motion
jggimi
29th July 2006, 23:41
In the quote from the tutorial, above, it says:A TRULY INTERLACED SOURCE CANNOT BE IVTC’D.

Apparently, that just wasn't clear enough. :rolleyes:
hkl8324
31st July 2006, 01:37
OK, thanks everyone...I think I will leave it as it is....29.97:D