#8590: 'telecine=pattern' error for p24, soft telecined sources
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Reporter: markfilipak | Owner:
Type: defect | Status: closed
Priority: normal | Component:
| undetermined
Version: unspecified | Resolution: invalid
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Comment (by pdr0):
Replying to [comment:29 markfilipak]:
>
> Ordinarily, at 30 FPS, 2-3-2-3 pull-down, of course I agree. But
consider this: At 30 FPS, the 2 combed frames abut, so blending is 5/12s
long and repeats @ 6Hz. But at 60 FPS, 5-5-5-5 pull-down, the 2 combed
frames are separated by 4 progressive frames, so blending is 1/60s plus
1/60s separated by 1/15s and blending repeats @ 12Hz. From my experience
based on experimentation, each combed frame is so brief that, even not
deinterlaced, they are unnoticable. You can reproduce it using the p24
that you gave me and 'telecine=pattern=5' (but without the deinterlace
part). I'm going to try to attach a 2MB comparison.
>
> I just viewed it. I see no blending. I see frames 3, 8, 13, 18, etc.
combed but not blended. That's exactly what I got and what you will see in
my attachment (if I can attach a 2MB file).
>
> > And yes, there is still judder , because you don't have a blend
inserted between BB , CC (BC), so there is a perceptual jump in motion
compared to AA(AB)BB , or CC(CD)DD .
>
> I think that most of what you're seeing as judder is actually twitter
from the combing. I think it would disappear if the combed fields could
actually be blended. Certainly, if it is judder, there's less of it than
for any other telecine scheme.
>
Are you looking at the correct file ?
blenddeint_combedonly.mp4
I took -vf "telecine=pattern=5", and that produces combing , we both
agree.
I took that encode out of ffmpeg, and applied a blend deinterlace to
affected combed frames . This is the end result is you wanted (albeit
partially done elsewhere)
Attached screenshot comparison
>
> The reason I say it's twitter, not judder, is that if you do the
calculations of average temporal location of the temporal center of the
pictures and their durations, the cadence really is
1/15s-1/15s-1/15s-1/15s.
>
"twitter" is a reserved term for something else
The 3rd frame (starting from frame 1) is what time? It's a blend of 2
times, whether or not you leave it as combed, vs. blend deinterlace.
There is still judder, because either you lack the BC blend (or comb, if
you didn't blend deinterlace) , or you have AB or CD inserts. Either way
you look at it , there is some judder. It's as I described above
{{{
AA(AB)BBCC(CD)DD
}}}
>
> Damn. What about while the 'telecine' output is still in fields? Can 2
fields be blended within a complex_filter?
>
> > You can't just blend the telecine output and replace specific frames,
because you'd get combed blends, not frame blends (as if frame blends
weren't bad enough...)
>
> "Combed blends"? Sorry, I don't know what you mean.
Actually, nevermind it won't happen here because you have single frames
combs only, never 2 or more in a row.
But to blend deinterlace, you need to blend the fields. Not sure how to do
this in ffmpeg. Maybe separate fields , use tblend and select in
filter_complex.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/8590#comment:30>
FFmpeg <https://ffmpeg.org>
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