On 02/04/2021 06:50 PM, Mark Filipak (ffmpeg) wrote:
For discussion: A better video notation.

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

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

[email protected]         (aka "24p") Cinema (i.e. 24pps) mastered at 23.9fps, 0.1% 
slow.
[email protected]         (aka "30i") Soft-telecined: cinema with 29.9fps metadata, 
0.1% slow.
24pps@25fps           (aka "25i") Cinema with 25fps metadata, 4% fast.
[email protected]         (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.
[email protected]       (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.
[email protected]       (aka "30i") NTSC broadcast TV, scan-interlaced, mastered 
at 29.9fps.
[email protected] (aka "30i") Mix of [email protected] & [email protected] -- some 
"Making of" docs.
[email protected]     (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.

[email protected] 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 '[email protected]'. Of course, that doesn't seem very intuitive, and novices will question it, at least at first. Perhaps '(24+6)[email protected]' expresses it better. Or maybe '6x(4+1)[email protected]' or maybe '6x(1-1-1-2)[email protected]'. 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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