Why do we have to convert 25 fps to 23.97 fps ?

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Re: Why do we have to convert 25 fps to 23.97 fps ?

Postby Snowcrash » Mon Sep 06, 2010 11:26 am

Yep I agree with that. Unfortunetaly there is not a lot of animes with an original rate at 25 fps.

And even if an animated movie was created in Europe, for example Les triplettes de Belleville or Persépolis, I suppose the animators do their work at 24 fps ?
And they convert it at 25 fps ?

If resume for converting :
- in NTSC countries (with japanese or american anime) :24fps --> -0.1% --> 23.97 fps --> 29.97 fps (telecine) so the converting operation is not too difficult.
- in PAL countries (with japanese or american anime) : 24 fps --> -0.1% --> 23.97 fps --> 29.97 fps (telecine) --> 25 fps so the converting operation is quiet messy :(
- in PAL countries (with european anime) : 24 fps --> 25 fps so conversion is just restore24 ?

Do I am right ? I suppose there are other cases but those are the main ones, aren't they ?
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Re: Why do we have to convert 25 fps to 23.97 fps ?

Postby Mister Hatt » Thu Sep 09, 2010 7:37 am

If your source is PAL, you need a new source. Your definitions are also a bit wrong. NTSC can be done several ways but it is at 23.976~ to start with, it is not slowed down from 24. PAL countries either process in some way to get from 23.976~ to 25 OR they decimate it down from 29.970 OR it is blended into a 25fps mess with one of several algorithms.

Restore24 does NOT do what you think it does. It is for attempting to reconstruct blend-converted data back to NTSC and then IVTC to 23.976.
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Re: Why do we have to convert 25 fps to 23.97 fps ?

Postby Snowcrash » Thu Sep 09, 2010 9:06 am

Mister Hatt wrote:NTSC can be done several ways but it is at 23.976~ to start with, it is not slowed down from 24.

I disagree with that : a film is shot at 24 fps not at 23.976 fps. Same for animation, an animator can't create 23.97 image >.>
You can read this page if you want to check : http://www.paradiso-design.net/videosta ... l#transfer

Mister Hatt wrote:PAL countries either process in some way to get from 23.976~ to 25

PAL countries don't start at 23.976 fps but 24 fps : they sped up the film at 25 fps to get the PAL standard. Of course if they get a NTSC video, it's a complete mess to do the transfer.

And a nice and very complicated figure to explain that :p
Spoiler :
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Re: Why do we have to convert 25 fps to 23.97 fps ?

Postby Mister Hatt » Thu Sep 09, 2010 9:45 pm

That is so fucking kawaii you have no idea. Unfortunately, I work in film production and I can assure you that 24fps is not the capture rate in most studios. I also work in importing overseas films and converting them to PAL (in fact it's my specialty) and you're wrong about that one as well. We speed up to 24fps from 23.976 and then apply a soft pulldown or a blend matrix to it. There are ways of getting NTSC->PAL without ruining it TOO badly, so I wouldn't call it a mess, but it is still far from ideal. Just because some junky website says it's done one way doesn't make it true. I'm speaking from industry experience here.
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Re: Why do we have to convert 25 fps to 23.97 fps ?

Postby post-it » Fri Sep 10, 2010 1:56 pm

why not just convert it to 120 fps and then divide it as needed ....
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Re: Why do we have to convert 25 fps to 23.97 fps ?

Postby mirkosp » Fri Sep 10, 2010 2:03 pm

post-it wrote:why not just convert it to 120 fps and then divide it as needed ....

Doesn't really change anything. When you convert to 120 you're just duplicating frames, and then you'd drop them again to go to the actually desired framerate... so the result is the same.
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Re: Why do we have to convert 25 fps to 23.97 fps ?

Postby post-it » Fri Sep 10, 2010 4:42 pm

.. then ... ? .. is there a place, somewhere in the video-stream, that has the frame-rate "written in it" ??

{ What I mean is; something "somewhere" should have the frame rate "used" and "converted-to" ... ? }
it would be rather silly "not" to have the play-back information available within it because SOMETHING has
to let the TV Signal know "when" to "switch fields" and "when its progressive" ... right? :?:
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Re: Why do we have to convert 25 fps to 23.97 fps ?

Postby Mister Hatt » Sat Sep 11, 2010 1:39 am

The 120fps hack is a dirty method of making pseudo-VFR in AVI containers. It is NEVER a good idea and serves only to make your encoding process take longer while using more ram and bitrate than necessary. You've been told like a hundred times by now post-it, stop giving people bad advice.
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Re: Why do we have to convert 25 fps to 23.97 fps ?

Postby post-it » Sat Sep 11, 2010 11:51 am

Mister Hatt wrote:The 120fps hack is a dirty method of making pseudo-VFR in AVI containers. It is NEVER a good idea and serves only to make your encoding process take longer while using more ram and bitrate than necessary. You've been told like a hundred times by now post-it, stop giving people bad advice.
I'm not giving advice, I'm asking questions: unlike you, I'm not GOD!

I've seen people converting files to 120 fps and wondered "why" but I never got an answer!
( this caused many people many problems during Romeo X Juliet; we set up IRC's for Corrections and
were swamped with know-it-all's like you! {{ check it out, it is recorded on the orgs listings! }})

At more than 10 times I've asked, "where are the stream markers located for Frame Rate" and recieved no answers!

I've asked many times on many different occasions, "how to do things" and the first thing I usually get is your fat-lip.

This board was put together for people to ask questions and find answers: No GODs Allowed! ( except Zero 8-) )

..

btw .. any of those three questions listed can be answered at any time Mister Hatt! Put-up -or- Shut-up!
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Re: Why do we have to convert 25 fps to 23.97 fps ?

Postby mirkosp » Sat Sep 11, 2010 12:20 pm

The real problem is that your wording makes people think you're trying to give suggestions instead of asking questions, post-it.
Anyway, if you want to know where the framerate info is stored, well, I assume that varies depending on the container and the codec, so there is no generic answer, but I wouldn't be able to tell where exactly that's stored for a certain format, it's not something I know nor I've ever searched for, since things like medianfo and avinaptic can already tell me the framerate of a given source, if I need to check it... but well, I guess if you feel like it, you might be able to find something by poking around in the file in a HEX editor.
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Re: Why do we have to convert 25 fps to 23.97 fps ?

Postby Snowcrash » Sun Sep 12, 2010 4:45 am

Spoiler :
Com'on Mirkosp I was always really nice when I ask some questions here but the replies of Mister Hatt were often unpleasant beween :
then either you're blind or you don't speak English well enough to know what "good" means.

That is so fucking kawaii you have no idea.

Just because some junky website says it's done one way doesn't make it true.

Apparently this website spreads some very bad knowledges about PAL-NTSC transfer because they're not working on industry movie (who knows?) >.>.


That's not very engageant for people who asking help in the helping section of Org (after that we ask ourselves why noobs are running away from org >.>).

At least I learned some stuff from Mister Hatt:
- a movie can be shot at 23.97 fps (with digital camera ?). I thought a 35 mm movie was shot at 24 fps but I suppose the european directors prefer shoot at 24 fps for an easier transfer on PAL DVD and US directors shoot at 23.97 fps because the NTSC transfer (23.97 to 29.97 fps) is more simple.
- there is many ways to do an conversion from NTSC to PAL DVD.
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Re: Why do we have to convert 25 fps to 23.97 fps ?

Postby post-it » Sun Sep 12, 2010 2:17 pm

Sn0wcrash wrote: I thought a 35 mm movie was shot at 24 fps ...
0_0 ..? .. hehe; I always thought 35 & 70mm were 18 fps T_T ( I've been watching too many .vbrm's and .viv files! ) .. x_x

. As far as Mister (MAD) Hatter's input goes; I'm not grasping his anger issues!

. mirkosp .. would it help if I added a Q: -or- ¿ to my questions .. so that you-all know when the statement is a question?
if so, then what should I use for a "comment" ? -- this english language seems to be getting me in trouble :cry:
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Re: Why do we have to convert 25 fps to 23.97 fps ?

Postby Snowcrash » Mon Sep 13, 2010 2:06 am

post-it wrote:0_0 ..? .. hehe; I always thought 35 & 70mm were 18 fps T_T ( I've been watching too many .vbrm's and .viv files! ) .. x_x

I don't know, but according Wikipedia (which is not God, everyone knows that XD), it seems to be 24 fps and 16 frames per foot for 35 mm.
It seems to be the same framerate for 70 mm movie but it depends of the format:
- 24 fps for Standard 65 mm (5/70)
- 60 fps for Showscan
- 24 or 30 for Dynavision
So it's quiet confusing but 24 fps seems to be the most common framerate for 35 and 70 mm film.
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Re: Why do we have to convert 25 fps to 23.97 fps ?

Postby Mister Hatt » Mon Sep 13, 2010 11:56 am

post-it wrote:I've seen people converting files to 120 fps and wondered "why" but I never got an answer!
( this caused many people many problems during Romeo X Juliet; we set up IRC's for Corrections and
were swamped with know-it-all's like you! {{ check it out, it is recorded on the orgs listings! }})
120fps is a hack used for faking VFR in AVI containers when your material is VFR. It's a form of VFRaC (VFR assumed Constant) and by using drop/null frames at an appropriate multiple of both rates you can simulate the variable rate to perfect accuracy. Unfortunately it makes files way larger than necessary.

post-it wrote:At more than 10 times I've asked, "where are the stream markers located for Frame Rate" and recieved no answers!
Probably because 99% of the time the actual relevant framerate info isn't stored in the stream and is done at the container level. It depends on the structure of the specific container. A stream inside a container DOES have it's own framerate (almost always the default for AVC is 25fps) but the container overrides it in most splitters. Again that would be specific to the codec standard.

That's only two questions that I can see though.

@Sn0wcrash: 35mm film obviously wouldn't be done at a fractional framerate due to math complications rather than impossibility. It is usually quite less though. I don't know of any anime on 35mm however. Read up on it if you're interested (you seem to have done a bit already) but this isn't really the place for it that I can tell.
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Re: Why do we have to convert 25 fps to 23.97 fps ?

Postby Snowcrash » Mon Sep 13, 2010 1:39 pm

Sn0wcrash wrote:I don't know of any anime on 35mm however. Read up on it if you're interested (you seem to have done a bit already) but this isn't really the place for it that I can tell.

Yeah I realized the topic of this thread changed a little bit :p
So forget the 35 mm.

But as you said before, you get a lot of stuff shot at 23.97 fps. Are you talking about anime ?
Usually, an animator has to create whole frames manually (for traditionnal animation). So how can you get a original material video at 23.97 fps (for anime) ?
Apparently old animes was animated at 12 fps (and after the frames were doubled to get a 24 fps rate).
But now do they their work at 24 fps or what ?
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