Author Topic: SD anime, 23.976 vs 29.970 fps ??  (Read 652 times)

Offline mugz

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SD anime, 23.976 vs 29.970 fps ??
« on: November 09, 2013, 11:50:35 AM »
I have read that most SD anime is actually created at 24 fps and that the 23.976 was a number come up with to try to return a film to its original frame rate without losing any frames, or at least, losing as few as possible. This is done for 2 reasons that I know of:

A lower frame rate allows for about 20% fewer frames which means you can have a higher bitrate (ie each frame will be "better quality" - given the same file size or same or a little better quality with smaller file size).

On the other hand, some say that they think the video may be more "jerky" at only 23.976 fps and that if its an NTSC source, you should keep the same frame rate as the source.

Opinions anyone?
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Online Al_Sleeper

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Re: SD anime, 23.976 vs 29.970 fps ??
« Reply #1 on: November 09, 2013, 11:56:11 AM »
In fact, 29.97 fps video is often much more jerky in panning scenes due to the method additional frames are generated with during 23.976 to 29.97 conversion.
As a rule, almost all Japanese animation is produced originally at 23.976 fps.
« Last Edit: November 09, 2013, 11:58:50 AM by Al_Sleeper »

Offline mugz

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Re: SD anime, 23.976 vs 29.970 fps ??
« Reply #2 on: November 09, 2013, 12:58:47 PM »
In fact, 29.97 fps video is often much more jerky in panning scenes due to the method additional frames are generated with during 23.976 to 29.97 conversion.
As a rule, almost all Japanese animation is produced originally at 23.976 fps.

Thanks Al, that's sorta the conclusion I was reaching myself, I mean, why WOULD it be better to keep the 29.976 frame rate if all it is is extra frames anyway? Your answer makes sense. Having higher quality frames also makes sense.
« Last Edit: November 09, 2013, 01:01:10 PM by mugz »
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Online cold_hell

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Re: SD anime, 23.976 vs 29.970 fps ??
« Reply #3 on: November 09, 2013, 02:00:21 PM »
In fact, 29.97 fps video is often much more jerky in panning scenes due to the method additional frames are generated with during 23.976 to 29.97 conversion.
As a rule, almost all Japanese animation is produced originally at 23.976 fps.
After TFM you just have one duplicate at every 5frames
So every frame stays ~0.03sec and one at every 5 stays ~0.06
on 23.976 evey frame stays about ~0.04sec

23.976 if preferable but if tdecimate fail to remove the correct (dup frames) it will cause really big spikes. So if you are able to remove all dupped frames without problems 23.976, if it fails too often (where manual fix is impossible) => 29.970

Offline mugz

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Re: SD anime, 23.976 vs 29.970 fps ??
« Reply #4 on: November 09, 2013, 03:03:23 PM »
23.976 if preferable but if tdecimate fail to remove the correct (dup frames) it will cause really big spikes. So if you are able to remove all dupped frames without problems 23.976, if it fails too often (where manual fix is impossible) => 29.970

What is the best setting for tdecimate for older anime? I have been using the MeGui Analyzer and script creator to get most of my script, (set for anime), to get my settings for decomb and tdecimate, then I modify adding the other settings and filters I want to use.

Also, what is the best way to tell if all the duped frames were removed properly, just by watching it or maybe go frame by frame in action/movement/panning parts of the film?
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Online cold_hell

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Re: SD anime, 23.976 vs 29.970 fps ??
« Reply #5 on: November 09, 2013, 03:50:13 PM »
For normal 29.970->23.976 nothing special really, while TFM has alot settings and you should read TFM - READ ME.txt (894 lines, not so big)

for most sources something like this will probably work fine
deint = (whatever deinterlacer you want to use).SelectEven()
TFM(slow=2, pp=2, mode=5 ,chroma=true, scthresh=6, cthresh=6, micmatching=3, clip2=deint).TDecimate(mode=1)
however all depends on the source

Offline mugz

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Re: SD anime, 23.976 vs 29.970 fps ??
« Reply #6 on: November 09, 2013, 04:01:56 PM »
For normal 29.970->23.976 nothing special really, while TFM has alot settings and you should read TFM - READ ME.txt (894 lines, not so big)

Yes RTFM - I heard that someplace else too :P
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Offline OnDeed

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Re: SD anime, 23.976 vs 29.970 fps ??
« Reply #7 on: November 09, 2013, 04:28:18 PM »
And if this wasn't clear, 23,976 fps (24000/1001) definitely isn't a thing of "SD" anime. Virtually everything is made at this framerate - which we often call just 24fps for simplicity, although it is not precise.

As for 29,970 fps, colloquially 30fps shows (the exact framerate is 30000/1001), there are mere few examples, and all that I know about are actually SD too:

Aria the animation (maybe the sequels too?), Kuttsukiboshi, Himawari! and Himawari!! (but at least in the case of the second season, the content was mixed - something was animated at 24fps and telecined, something was 30 fps).

Most of the stuff you will see encoded at 30 fps is actually just something that the encoders messed up and in reality it is 24fps.

Offline Krudda

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Re: SD anime, 23.976 vs 29.970 fps ??
« Reply #8 on: November 09, 2013, 08:15:43 PM »
You'll find that, if properly done, a 29.970fps encoded file won't end up larger than the 23.976fps encoded file (a tiny bit, but bugger all)
The issue is as everyone else here stated, the frames are choppy due to the 'extras' included.

I doubt I need to explain more, as everyone seems to have covered it well already, though you will benefit from reading the following link.

http://en.wikipedia.org/wiki/24p

It's a little bit confusing for beginners (and some parts are still confusing for me :s, but overall, it will definitely help you understand the way framerate works and why)
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Offline OnDeed

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Re: SD anime, 23.976 vs 29.970 fps ??
« Reply #9 on: November 10, 2013, 06:29:21 PM »
You'll find that, if properly done, a 29.970fps encoded file won't end up larger than the 23.976fps encoded file (a tiny bit, but bugger all)

This is not necessarily true. Consider this: if your source is hard telecine, then there will be unique fields in the repeated frames. Any noise in them will cause the "dupes" to be significantly different and it won't nearly compress in low amount of bytes.

BTW, x264 now adjusts its compression based on input framerate, so unless you override, it will treat a 29,970fps input more roughly than a 23,976fps source.