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

[Mister Hatt]

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 ?

This might come as a shock but you're making the incorrect assumption that a scene is animated by the second. 23.976fps might be a fractional rate by the second but for a standard you will find that it's usually about 35,000 frames. Animators work by the number of frames, not the rate they are played at. If they believe that a scene needs to be smoother, they will give it more frames and a higher rate. Nobody animates saying "I want it to be this rate" though; it's just that for a decent motion range they know how many frames to throw over a period of time so that you end up with 23.976fps as a baseline. I hope this clears it up a bit.

As far as frameserving without nulls, avisource("your-video-with-null-frames.avi") will do it. If however your encoder sucked and encoded non-nulls by actually duplicating the frames and hard encoding, then getting it back to normal is considerably harder and I can't think of an easy way to do it consistently well. So if you need 120fps, do it properly in the first place; Tritical wrote a cool toy for doing it, part of avi_tc_package IIRC.

[Snowcrash]

Nobody animates saying "I want it to be this rate" though; it's just that for a decent motion range they know how many frames to throw over a period of time so that you end up with 23.976fps as a baseline. I hope this clears it up a bit.

Thanks a lot. It's effectivelly more clear for me
So the animators do their frames and after they end up at the target framerate on the baseline.
But isn't it easier to end up at 29.97 fps (or 25 fps) instead 23.97 to get directly the right framerate for NTSC (or PAL) standard (depending if the anime is done in NTSC or PAL country) ?

And Kazend :

http://i25.servimg.com/u/f25/11/05/55/21/bd_pal10.jpg

PAL will win ! XD

[post-it]

.. Making a VFR encode will effectively delete the duplicate frames, it'll just remember in a timecode file for how long they are to be shown, but if you ignore the timecode file, you can just get the output you want.

^_^ I was over-thinking the problem; soo close to the answer that I missed it X_X

THx That did it ^_^

[Mister Hatt]

But isn't it easier to end up at 29.97 fps (or 25 fps) instead 23.97 to get directly the right framerate for NTSC (or PAL) standard (depending if the anime is done in NTSC or PAL country) ?

No, because they have to draw more, and converting between standards is a lot easier when your baseline is FILM. Not to mention that NTSC and PAL are standards for SD only and most stuff is HD now. As for older stuff, it was often made for display in cinemas and whatnot so using FILM rates made sense, along with the aforementioned standards conversion point.

[Snowcrash]

Ok I think I got all the explanations I want ^^

Just a last thing. Now with the HD video (blu-ray), it seems the framerate of this support is commonly 24 fps. Is it a will to simplify the problem of different framerate around the world ?

[mirkosp]

Actually, all the anime blurays I have ripped so far were either 23.976 progressive or 59.94 interlaced with MBAFF and a lot of annoying stuff to deal with...

[Snowcrash]

Actually, all the anime blurays I have ripped so far were either 23.976 progressive or 59.94 interlaced with MBAFF and a lot of annoying stuff to deal with...

Damned
I suppose 23.976 progressive is not a bad deal but what is 59.94 interlaced with MBAFF ?
And do you rip a blu-ray with a specific software ?
Actually I think the Blu-Ray ripping shoud have another thread ^^

[mirkosp]

MBAFF is a kind of interlace that AVC streams can have. Basically the image is separed into blocks, and each block could be either progressive or interlaced. So in the same stream you could have content telecined to 29.97, progressive at 29.97, interlaced at 59.94, and even combinations of two or more in the same frame, considering the block division. It is possible to find vfr material on DVD, however on DVDs you don't have different content separed into blocks (you can have telecined content with full field interlaced content on top, though, and that isn't nice ), so it's easier to deal with. OTOH, if you find content a section in a MBAFF stream that has both progressive and interlaced blocks in the same frame, you have to either do a lot of fancy stacking to keep the progressive footage as progressive and treat the interlaced/telecined content properly, or just nuke the whole thing, which could lead to a loss of quality in the progressive parts of the image. There probably exist some filters that can recognize progressive content and leave it alone while dealing with the interlaced content, but I'm not sure which/how good they are. IIRC I was told that some versions of tempgauss_mc can do that, but there are over 9000 versions of it around so it's kinda hard to know which do and which don't, if any version actually does...

[Mister Hatt]

Bluray has a few standards. By far the most common is 1920x1080p24, but 1920x1080i60 and 1440x1080i60 are common enough as well. Note that all those rates are at the 1% reduced rate. So basically 23.976fps progressive or 29.970fps interlaced. As mirko said, sometimes you get (actually nobody else I know gets them, mirko just has INCREDIBLY bad luck and encodes shitty shows anyway) the evil shit called MBAFF. Don't ever try to deal with it, instead send an angry email to the producer.

As for simplifying framerate problems around the world, digital televisions aren't required to have a default framerate, they just interpolate the served frames to whatever their refreshrate is (usually 120Hz, so it works well with p much everything, or 200Hz for dumb companies that think it looks better with motion failure) so it really makes no difference what the source rate is. Only analogue TV's are restricted by rate in what they can show and that's only because of the electrical power frequency in the electron gun of the CRT. PAL countries use 50Hz powerlines, NTSC countries use 60Hz powerlines. That's where the rates came from for field refreshing. So with HD, there are none of these issues, as the display has a much higher refresh rate and just interpolates (usually they just dumb-duplicate tho) and gives you a clean 120Hz image. For example, 24-1% video gets duplicated 5x per frame, while 30-1% gets duplicated 4x. 60fps gets doubled. Most displays are progressive and deinterlace with <methods> so that you end up not refreshing by field but if you choose to, there are ways to work with that too.

tl;dr MBAFF sucks ass and you should never use it ever because it's just annoying and stuff. Even YATTA has issues with it. Framerate standardisation on HD is irrelevant.

[Snowcrash]

I think this thread was very instructive for me (and other people I hope) about framerates and other stuff. It's really more clear for me anyways (between the framerate and refreshrate, etc...)

About HD, I understand it's easier to get downloaded source instead a Blu-Ray rip apparently

But I am thinking about a recent HD AMV made by Bauzi. According what you said, Blu-ray are 23.976 fps or 29.97 fps (and not really 24 fps actually).

Bluray has a few standards. By far the most common is 1920x1080p24, but 1920x1080i60 and 1440x1080i60 are common enough as well. Note that all those rates are at the 1% reduced rate. So basically 23.976fps progressive or 29.970fps interlaced.

But the framerate of the video of Bauzi is 24 fps and not 23.976 fps. Did he do something wrong with the fps ?
Here is the link of his thread : http://www.animemusicvideos.org/forum/v ... 3&t=101478