For discussion: A better video notation.

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For discussion: A better video notation.

Mark Filipak (ffmpeg)
For discussion: A better video notation.

24PPS@23.9FPS         (aka "24p") Cinema (i.e. 24PPS) mastered at 23.9FPS, 0.1% slow.
24PPS@23.9FPS         (aka "30i") Soft-telecined: cinema with 29.9FPS metadata, 0.1% slow.
24PPS@25FPS           (aka "25i") Cinema with 25FPS metadata, 4% fast.
24PPS@29.9FPS         (aka "30i") Hard-telecined: cinema converted to 29.9FPS, 0.1% slow.
25PPS@25FPS           (aka "25i") Cinema interpolated to 25PPS, no speed up.
29.9PPS@29.9FPS       (aka "30p") 29.9PPS video at 29.9FPS (some documentaries).
50SPS@25FPS           (aka "25i") PAL broadcast TV interlaced to 25FPS.
50SPS+24PPS@25FPS     (aka "25i") Mix of 50SPS@25FPS & 24PPS@25FPS (some "Making of" docs).
59.9SPS@29.9FPS       (aka "30i") NTSC broadcast TV interlaced to 29.9FPS.
59.9SPS+24PPS@29.9FPS (aka "30i") Mix of 59.9SPS@29.9FPS & 24PPS@29.9FPS (some "Making of" docs).
IRREGULAR@29.9FPS     (aka "30i") Having various frame/field repeats/discards with image loss.

--
I don't have a dog.
And furthermore, my dog doesn't bite.
And furthermore, you provoked him.
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Re: For discussion: A better video notation.

Carl Zwanzig
On 2/4/2021 3:50 PM, Mark Filipak (ffmpeg) wrote:
> For discussion: A better video notation.

Well, none of them go with the industry standards like 1920p30 or 480i29.97.
Consider that the main notation expresses resolution and frame/field rate of
the encoded video itself and isn't concerned with how those frames were
generated. It sounds like you're trying to express how something was
processed before being put into that encoding/container.

For instance-
> 59.9SPS@29.9FPS       (aka "30i") NTSC broadcast TV interlaced to 29.9FPS.
480i29.97 is understood to be digital "NTSC" with non-square pixels and
drop-frame rate. It's often shortened to "480i" since NTSC seldom occurs in
the wild as non-drop-frame. Nothing else is particularly needed.

Later,

z!

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Re: For discussion: A better video notation.

Mark Filipak (ffmpeg)
On 02/04/2021 07:20 PM, Carl Zwanzig wrote:
> On 2/4/2021 3:50 PM, Mark Filipak (ffmpeg) wrote:
>> For discussion: A better video notation.
>
> Well, none of them go with the industry standards like 1920p30 or 480i29.97...

Those, more standard notations are where I began. But in order to differentiate between all the
formats that are simply called "30i", for example, I had to start adding letters that just made it
all too cryptic. A couple of days ago I realized that if I simply differentiated based on PPS
(pictures per second), then it became relatively simple. I'm sure you'll agree that a 24PPS movie
that's been hard-telecined and encoded as 29.9FPS is still 24 pictures/second.

>... Consider that the main
> notation expresses resolution and frame/field rate of
> the encoded video itself and isn't concerned with how those frames were
> generated. It sounds like you're trying to express how something was
> processed before being put into that encoding/container.

Yes! Exactly! When one is trying to recreate the original presentation, "how those frames were
generated" is crucial.

> For instance-
>> 59.9SPS@29.9FPS       (aka "30i") NTSC broadcast TV interlaced to 29.9FPS.
> 480i29.97 is understood to be digital "NTSC" with non-square pixels and drop-frame rate. It's often
> shortened to "480i" since NTSC seldom occurs in the wild as non-drop-frame. Nothing else is
> particularly needed.

But it does occur in the wild. It's interlaced to frames, and players generally decomb it, but 59.9
scans/second set to 29.9 frames/second is very common, especially in special feature documentaries
that are made for TV and later included on DVDs and BDs.

> Later,
>
> z!

--
I don't have a dog.
And furthermore, my dog doesn't bite.
And furthermore, you provoked him.
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Re: For discussion: A better video notation.

Jim DeLaHunt-2
In reply to this post by Mark Filipak (ffmpeg)
On 2021-02-04 15:50, Mark Filipak (ffmpeg) wrote:

> For discussion: A better video notation.
>
> 24PPS@23.9FPS         (aka "24p") Cinema (i.e. 24PPS) mastered at
> 23.9FPS, 0.1% slow.
> 24PPS@23.9FPS         (aka "30i") Soft-telecined: cinema with 29.9FPS
> metadata, 0.1% slow.

The notation codes for these two examples look identical to me.

Perhaps the second one should have been "30PPS@29.9FPS"?

Also, I'll point out that that this notation seems to have an
obfuscation of its own, when it says "23.9". Does that actually mean
"24/1.001"? It would be nice if the notation said that, so that we could
distinguish it from the number, "239/10".

Best regards,
      —Jim DeLaHunt


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Re: For discussion: A better video notation.

Carl Zwanzig
On 2/4/2021 7:54 PM, Jim DeLaHunt wrote:
> I'll point out that that this notation seems to have an obfuscation of its
> own, when it says "23.9".

Yes, that should be 23.97 (or .98?) if not the fraction; same for 29.97 or
the fraction.

Later,

z!
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Re: For discussion: A better video notation.

Mark Filipak (ffmpeg)
In reply to this post by Jim DeLaHunt-2
On 02/04/2021 10:54 PM, Jim DeLaHunt wrote:

Thanks, Jim,

> On 2021-02-04 15:50, Mark Filipak (ffmpeg) wrote:
>
>> For discussion: A better video notation.
>>
>> 24PPS@23.9FPS         (aka "24p") Cinema (i.e. 24PPS) mastered at 23.9FPS, 0.1% slow.
>> 24PPS@23.9FPS         (aka "30i") Soft-telecined: cinema with 29.9FPS metadata, 0.1% slow.
>
> The notation codes for these two examples look identical to me.

They _are_ identical. A soft-telecined video is actually 23.9fps but with 29.9fps metadata. In other
words, you wouldn't want to detelecine it, eh?

> Perhaps the second one should have been "30PPS@29.9FPS"?
>
> Also, I'll point out that that this notation seems to have an obfuscation of its own, when it says
> "23.9". Does that actually mean "24/1.001"? ...

You know, I'm kinda ambivalent. Of course, 24/1.001fps needs to be differentiated from 24fps, but
I'm not sure 24fps actually exists on any DVD or BD. That 'said', I originally used '/1.001' but I
thought that it added nothing other than that it's not 24fps or 30fps or 60fps. Now, it's a fact
that there are several players and software packages that use '23fps' and '29fps' and '59fps'. I
understand why they do that though I don't like it much and first thought it was an error. I thought
that '23.9', '29.9', and '59.9' was a good compromise. But I'm pretty agnostic on the whole issue.
Let's see what consensus emerges.

>... It would be nice if the notation said that, so that we
> could distinguish it from the number, "239/10".
>
> Best regards,
>       —Jim DeLaHunt

--
I don't have a dog.
And furthermore, my dog doesn't bite.
And furthermore, you provoked him.
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Re: For discussion: A better video notation.

Mark Filipak (ffmpeg)
In reply to this post by Carl Zwanzig
On 02/05/2021 12:10 AM, Carl Zwanzig wrote:
> On 2/4/2021 7:54 PM, Jim DeLaHunt wrote:
>> I'll point out that that this notation seems to have an obfuscation of its own, when it says "23.9".
>
> Yes, that should be 23.97 (or .98?) if not the fraction; same for 29.97 or the fraction.

Well, if the choice is between one decimal (23.9) or two decimals (23.98) or three decimals
(23.976), my vote goes to fraction.

> Later,
>
> z!
--
I don't have a dog.
And furthermore, my dog doesn't bite.
And furthermore, you provoked him.
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Re: For discussion: A better video notation.

Mark Filipak (ffmpeg)
In reply to this post by Mark Filipak (ffmpeg)
On 02/04/2021 06:50 PM, Mark Filipak (ffmpeg) wrote:

> For discussion: A better video notation.
>
> 24PPS@23.9FPS         (aka "24p") Cinema (i.e. 24PPS) mastered at 23.9FPS, 0.1% slow.
> 24PPS@23.9FPS         (aka "30i") Soft-telecined: cinema with 29.9FPS metadata, 0.1% slow.
> 24PPS@25FPS           (aka "25i") Cinema with 25FPS metadata, 4% fast.
> 24PPS@29.9FPS         (aka "30i") Hard-telecined: cinema converted to 29.9FPS, 0.1% slow.
> 25PPS@25FPS           (aka "25i") Cinema interpolated to 25PPS, no speed up.
> 29.9PPS@29.9FPS       (aka "30p") 29.9PPS video at 29.9FPS (some documentaries).
> 50SPS@25FPS           (aka "25i") PAL broadcast TV interlaced to 25FPS.
> 50SPS+24PPS@25FPS     (aka "25i") Mix of 50SPS@25FPS & 24PPS@25FPS (some "Making of" docs).
> 59.9SPS@29.9FPS       (aka "30i") NTSC broadcast TV interlaced to 29.9FPS.
> 59.9SPS+24PPS@29.9FPS (aka "30i") Mix of 59.9SPS@29.9FPS & 24PPS@29.9FPS (some "Making of" docs).
> IRREGULAR@29.9FPS     (aka "30i") Having various frame/field repeats/discards with image loss.

I decided that using lower case was more readable. What do you think?

24pps@23.9fps         (aka "24p") Cinema (i.e. 24pps) mastered at 23.9fps, 0.1% slow.
24pps@23.9fps         (aka "30i") Soft-telecined: cinema with 29.9fps metadata, 0.1% slow.
24pps@25fps           (aka "25i") Cinema with 25fps metadata, 4% fast.
24pps@29.9fps         (aka "30i") Hard-telecined: cinema mastered at 29.9fps, 0.1% slow.
25pps@25fps           (aka "25i") Cinema interpolated to 25pps, mastered at 25fps, no speed up.
29.9pps@29.9fps       (aka "30p") 29.9pps video mastered at 29.9fps -- some documentaries.
50sps@25fps           (aka "25i") PAL broadcast TV, scan-interlaced, mastered at 25fps.
50sps+24pps@25fps     (aka "25i") Mix of 50sps@25fps & 24pps@25fps -- some "Making of" docs.
59.9sps@29.9fps       (aka "30i") NTSC broadcast TV, scan-interlaced, mastered at 29.9fps.
59.9sps+24pps@29.9fps (aka "30i") Mix of 59.9sps@29.9fps & 24pps@29.9fps -- some "Making of" docs.
irregular@29.9fps     (aka "30i") Having various frame or field discards with temporal image loss.

This system is extensible to non-DVD/-BD transcodes (e.g. @59.9fps) but I'm a bit miffed by some
DVDs that I've encountered.

For example, I have a couple of DVDs from Korea that are @29.9fps but get there via frame repeat,
not via telecine -- of course the judder was awful until I fixed it.

24pps@29.9fps doesn't fit such a case because the original 24fps can't be obtained via detelecine,
but by dropping the repeated frame, instead. So I'm playing with such frame repeats by something
like '24pps+6pps@29.9fps'. Of course, that doesn't seem very intuitive, and novices will question
it, at least at first. Perhaps '(24+6)pps@29.9fps' expresses it better. Or maybe
'6x(4+1)pps@29.9fps' or maybe '6x(1-1-1-2)pps@29.9fps'. Whatever, things get messy.

--
I don't have a dog.
And furthermore, my dog doesn't bite.
And furthermore, you provoked him.
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