Judder-free, 60 FPS telecine (?)

General questions or discussion about HandBrake, Video and/or audio transcoding, trends etc.
markfilipak
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Re: Judder-free, 60 FPS telecine (?)

Post by markfilipak »

So far, 55-telecine has been universally rejected and I've been ridiculed for proposing it. Frankly, I'm amazed. I think it's rejection is caused by abstraction of video metrics to numbers instead of pictures and reasoning. Well, I have some numbers, too.

23-telecine produces 30FPS video having 12Hz judder of high contrast edges that persists for 8 ms plus 40% combing @ 6Hz.
46-telecine produces 60FPS video having 12Hz judder for 8 ms but no combing.
55-telecine produces 60FPS video having no judder and limits combing to 20% @ 12Hz.
12Hz & 10 ms are generally used as rule-of-thumb thresholds for human perception beyond which average noticeability drops off sharply.

Code: Select all

|<--------------------------1/6s-------------------------->|
[A/a__________][B/b__________][C/c__________][D/d__________]  p24 Source = 42ms/frame
:           ::::              :           ::::              : Judder = 8ms (i.e., 20%) @ 12Hz
[A/a_______][B/b_______][B/c_______][C/d_______][D/d_______]  p30 23-telecine
                        ::::::::::::::::::::::::              Combing = 67ms (i.e., 40%) @ 6Hz

Code: Select all

|<--------------------------1/6s-------------------------->|
[A/a__________][B/b__________][C/c__________][D/d__________]  p24 Source = 42ms/frame
:           ::::              :           ::::              : Judder = 8ms (i.e., 20%) @ 12Hz
[A/a_][A/a_][B/b_][B/b_][B/b_][C/c_][C/c_][D/d_][D/d_][D/d_]  p60 46-telecine
                                                              Combing = none

Code: Select all

|<--------------------------1/6s-------------------------->|
[A/a__________][B/b__________][C/c__________][D/d__________]  p24 Source = 42ms/frame
:              :              :              :              : Judder = none
[A/a_][A/a_][A/b_][B/b_][B/b_][C/c_][C/c_][C/d_][D/d_][D/d_]  p60 55-telecine
            ::::::                        ::::::              Combing = 17ms (i.e., 20%) @ 12Hz
Lostless
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Re: Judder-free, 60 FPS telecine (?)

Post by Lostless »

It’s universally rejected because it has no real world use outside your use. The math doesn’t add up and Combing is bad in a progressive system.
But I love teaching and questioning. So this is not a ridicule of you, but I think you fundamentally misunderstand how pull down works.
There is no such thing as 4:6 pull down. 2:3 pull down is used In Progressive and interlaced systems. A 30i system is essentially a 60FPS medium. Each field represents 1/60th of a second. So 3:2 pull down is talking about putting 1 film frame into 3 fields/frames depending if your on a progressive system or interlaced. Followed by the next film frame into 2 fields/frames. Which is where telecine comes in. Its about putting a 24fps film into an interlaced system. It’s not talking about using 3 progressive frames followed by 2 interlaced frames..
I hope this makes sense.
markfilipak
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Re: Judder-free, 60 FPS telecine (?)

Post by markfilipak »

Lostless wrote: Wed May 06, 2020 3:11 pm It’s universally rejected because it has no real world use outside your use. The math doesn’t add up and Combing is bad in a progressive system.
What math doesn't add up?
When telecining p24 to p30 or p60, combing is the result. How else can you add the additional frames? Would you add blank frames? Would you repeat whole frames?
But I love teaching and questioning. So this is not a ridicule of you, but I think you fundamentally misunderstand how pull down works.
Trust me. I know what pull-down is.
There is no such thing as 4:6 pull down.
Of course there is.

Code: Select all

|<--------------------------1/6s-------------------------->|
[A/a__________][B/b__________][C/c__________][D/d__________]  p24 Source
 1-2---3-4   1-2---3-4---5-6
[A/a_][A/a_][B/b_][B/b_][B/b_][C/c_][C/c_][D/d_][D/d_][D/d_]  p60 46-telecine
It works by the same method as 23-telecine:

Code: Select all

|<--------------------------1/6s-------------------------->|
[A/a__________][B/b__________][C/c__________][D/d__________]  p24 Source
 1-2         1-2---------3 1---------2 1---------2-3
[A/a_______][B/b_______][B/c_______][C/d_______][D/d_______]  p30 23-telecine
2:3 pull down is used In Progressive and interlaced systems.
Pull-down is not used in interlaced video.
A 30i system is essentially a 60FPS medium.
i30 is 60 frames/second? This is absurd.
Each field represents 1/60th of a second.
You have a really screwed up concept of video. For NTSC, each field represents 1/60th sec. But for progressive (cinema) content that's telecined, each 1/30th sec. frame (not field) represents 4/5th of a film frame.
So 3:2 pull down is talking about putting 1 film frame into 3 fields/frames depending if your on a progressive system or interlaced.
Except for the beginning of the stream, 23 pull-down and 32 pull-down are the same thing -- reversing the numbers makes no apprecable difference. What is a "progressive system"? What is an "interlaced system"?
Followed by the next film frame into 2 fields/frames. Which is where telecine comes in. Its about putting a 24fps film into an interlaced system. It’s not talking about using 3 progressive frames followed by 2 interlaced frames..
I hope this makes sense.
You are majorly screwed up. Contact me off-list.
Lostless
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Re: Judder-free, 60 FPS telecine (?)

Post by Lostless »

https://youtu.be/5eu_KjKsnpM
You might find this video entertaining.
For my terms interlaced systems vs progressive system. We will go with 60hrz cause it’s what we are taking about. Both “systems”
(Maybe a poor choice of word, but it’s what I’m gong with. The concept is what matters) are a 60FPS medium. Meaning both are capable of displaying up to 60FPS. Now how they displayed is quite different. The signal of a interlaced system comes in at 30 frames per second, but each field contains a half Vertical resolution frame of 60fps. If you simply bob, up and down between the 2 fields, you can extract 60fps. Now the content inside may not be 60fps. Like a film, or a 30fps show. progressive system just contains 60 full resolution images and comes in at 60fps.
Basically what I’m saying is that 3:2 pull down applies the same
For both. But instead of a ratio of 2/3 frames for progressive, it’s 2/3 fields for interlace. The 1234456788 cadence is a poorly deinterlaced film to 30fps and is not telecine.
markfilipak
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Re: Judder-free, 60 FPS telecine (?)

Post by markfilipak »

Lostless wrote: Wed May 06, 2020 5:37 pm https://youtu.be/5eu_KjKsnpM
You might find this video entertaining.
For my terms interlaced systems vs progressive system. We will go with 60hrz cause it’s what we are taking about. Both “systems”
(Maybe a poor choice of word, but it’s what I’m gong with. The concept is what matters) are a 60FPS medium. Meaning both are capable of displaying up to 60FPS. Now how they displayed is quite different. The signal of a interlaced system comes in at 30 frames per second, but each field contains a half Vertical resolution frame of 60fps. If you simply bob, up and down between the 2 fields, you can extract 60fps. Now the content inside may not be 60fps. Like a film, or a 30fps show. progressive system just contains 60 full resolution images and comes in at 60fps.
Basically what I’m saying is that 3:2 pull down applies the same
For both. But instead of a ratio of 2/3 frames for progressive, it’s 2/3 fields for interlace. The 1234456788 cadence is a poorly deinterlaced film to 30fps and is not telecine.
Please contact me off-list. You have many understandably bogus concepts and I don't want to swamp this topic with the help that you need and that I can provide. I wrote "understandably" because there are many people who carry your misconceptions and innocently propagate them, including on Wikipedia.
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Rodeo
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Re: Judder-free, 60 FPS telecine (?)

Post by Rodeo »

I think it's fair to say this thread has outlived its usefulness.

Mark, please try and be a bit more respectful of others, else you won't last much longer here.
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