Decomb Custom syntax

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markfilipak
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Re: Decomb Custom syntax

Post by markfilipak » Mon Sep 16, 2019 5:03 pm

BradleyS wrote:
Mon Sep 16, 2019 4:52 pm
The beauty of interlacing detection is where no combing artifacts are detected, the frame passes untouched, preserving resolution and sharpness that is typically diminished by any deinterlacing algorithm.
I fail to see how deinterlacing diminishes resolution. Can you elaborate?

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BradleyS
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Re: Decomb Custom syntax

Post by BradleyS » Mon Sep 16, 2019 5:12 pm

Naturally, as interlacing depends on fields from two different points in time, interpolating these fields reconstructs neither exact point in time, but a combination of the two. Algorithms attempt various processing techniques to minimize any visual aberration, but none are perfect.

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Re: Decomb Custom syntax

Post by markfilipak » Mon Sep 16, 2019 5:34 pm

BradleyS wrote:
Mon Sep 16, 2019 5:12 pm
Naturally, as interlacing depends on fields from two different points in time, interpolating these fields reconstructs neither exact point in time, but a combination of the two. Algorithms attempt various processing techniques to minimize any visual aberration, but none are perfect.
Unless I'm missing something, saying the deinterlacing mixes fields from 2 different times (i.e., discreet fields) and therefore deinterlacing reduces resolution is misleading. There is such a thing as progressive sources that have interlaced fields. I have some, and they're from DVDs (and I'm not referring to soft telecine).

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BradleyS
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Re: Decomb Custom syntax

Post by BradleyS » Mon Sep 16, 2019 5:38 pm

30i is 60p with each field being half of two consecutive frames in the 60p source. These frames are 1/60 second apart, thus the interlaced fields in 30i are 1/60 second apart.

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Re: Decomb Custom syntax

Post by markfilipak » Mon Sep 16, 2019 6:35 pm

BradleyS wrote:
Mon Sep 16, 2019 5:38 pm
30i is 60p with each field being half of two consecutive frames in the 60p source. These frames are 1/60 second apart, thus the interlaced fields in 30i are 1/60 second apart.
I am ...mystified. "30i is 60p"? "60p source"? i30 has p60 sources? "frames are 1/60 second apart"? I can't believe that what I read is from you.

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BradleyS
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Re: Decomb Custom syntax

Post by BradleyS » Mon Sep 16, 2019 6:45 pm

Yep, and bob deinterlace creates 60p, naturally reducing some of the perceived resolution in order to recreate motion.

60p frames: A1 A2 A3 A4

30i frames: B1="top field of frame A1, bottom field of frame A2" B2="top field of frame A3, bottom field of frame A4"

This is how standard interlacing works. It does not mean that the original camera shot 60p, only that each field in 30i is 1/60 second apart and conceptually half of a 60p frame.

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Re: Decomb Custom syntax

Post by markfilipak » Mon Sep 16, 2019 7:16 pm

ohmygod. Is that the way you folks are thinking? Holy Cow.

You contend that i30 frames are composed of two p60 frames, as though 720x240 is a frame?

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BradleyS
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Re: Decomb Custom syntax

Post by BradleyS » Mon Sep 16, 2019 7:40 pm

My work in broadcast video aside, perhaps the Wikipedia page on interlacing can be of service: https://en.wikipedia.org/wiki/Interlaced_video

"This effectively doubles the time resolution (also called temporal resolution) as compared to non-interlaced footage (for frame rates equal to field rates)."

"A Phase Alternating Line (PAL)-based television set display, for example, scans 50 fields every second (25 odd and 25 even). The two sets of 25 fields work together to create a full frame every 1/25 of a second (or 25 frames per second), but with interlacing create a new half frame every 1/50 of a second (or 50 fields per second)."

markfilipak
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Re: Decomb Custom syntax

Post by markfilipak » Mon Sep 16, 2019 9:36 pm

BradleyS wrote:
Mon Sep 16, 2019 7:40 pm
My work in broadcast video aside, perhaps the Wikipedia page on interlacing can be of service: https://en.wikipedia.org/wiki/Interlaced_video
Surely you know how much nonsense there is at Wikipedia. It makes me cringe.
"This effectively doubles the time resolution (also called temporal resolution) as compared to non-interlaced footage (for frame rates equal to field rates)."
"This"? What's the antecedent? There is no doubled time resolution -- well, in a sense I guess there is, but saying that is like saying that cutting an apple in half makes 2 apples. The i30 is composed of two discrete fields (as from an NTSC camera). Calling that "p60" is going to confuse people. I can live with folks calling the odd field the "top field" and the even-field the "bottom field", but calling i30, "p60" is too much. And saying that a field is a frame is not correct. Sorry.

I'm guessing that when I wrote

Code: Select all

         p24 = [A/a][B/b][C/c][D/d]
         i30 = [A][a][B][b][C][c][D][d][E][e]
         p30 = [A/a][B/b][C/c][D/d][E/e]
p30-telecine = [A/a][B/b][B/c][C/d][D/d]
you didn't know to what I referred, eh? Take a look at it. Think about it. It's a little more explicit (and more compact) than A1 A2 A3 ... B1 B2 B3 ... I thought that my notation for p24 was enough of a clue to figure out the rest.
"A Phase Alternating Line (PAL)-based television set display, for example, scans 50 fields every second (25 odd and 25 even). The two sets of 25 fields work together to create a full frame every 1/25 of a second (or 25 frames per second), but with interlacing create a new half frame every 1/50 of a second (or 50 fields per second)."
Note that that particular Wikipedia author uses "odd" and "even". ;-)

I have NTSC & HDTV circuit & chip design experience.

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BradleyS
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Re: Decomb Custom syntax

Post by BradleyS » Mon Sep 16, 2019 9:46 pm

I only linked the post to hopefully reaffirm that each field is captured at two different points in time. That bob deinterlacing can deinterlace a source by "bobbing" between fields at twice the 25i/30i frame rate to create half resolution 50p/60p, usually with interpolation to produce the original resolution (albeit imperfectly), should answer your questions as to why some people choose to think of it as such. Nobody is calling 30i 60p, only explaining the relationship one to another as a way of thinking about it.

I have not read all of your posts in full as I simply do not have the time.

Anyway, your experience notwithstanding, these kinds of questions are best suited to other forums. Answering basic video questions like this is starting to consume time we'd rather be spending on helping people use HandBrake, or developing HandBrake. Hopefully you understand.

markfilipak
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Re: Decomb Custom syntax

Post by markfilipak » Mon Sep 16, 2019 9:46 pm

Ah, I owe you a partial appology. I thought you were aware of viewtopic.php?f=6&t=39355#p185860 but now I see you didn't participate in that topic.

markfilipak
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Re: Decomb Custom syntax

Post by markfilipak » Mon Sep 16, 2019 9:49 pm

BradleyS wrote:
Mon Sep 16, 2019 9:46 pm
... Anyway, your experience notwithstanding, these kinds of questions are best suited to other forums.
What other forum?

musicvid
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Re: Decomb Custom syntax

Post by musicvid » Tue Sep 17, 2019 2:00 am


markfilipak
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Re: Decomb Custom syntax

Post by markfilipak » Tue Sep 17, 2019 3:33 am

Thanks. I didn't see a HandBrake discussion sub-forum, but maybe there's one there. I'll look it over.

rollin_eng
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Re: Decomb Custom syntax

Post by rollin_eng » Tue Sep 17, 2019 9:35 am

markfilipak wrote:
Mon Sep 16, 2019 9:49 pm
BradleyS wrote:
Mon Sep 16, 2019 9:46 pm
... Anyway, your experience notwithstanding, these kinds of questions are best suited to other forums.
What other forum?
Seems like the ‘General Questions’ or ‘Tiki’ forum would be best.

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