Re: 'Interlace Detection' & 'Interlace'
Posted: Sat Sep 14, 2019 2:58 pm
yep. scarce as hens' teeth, I'd say
The open source video transcoder
https://forum.handbrake.fr/
yep. scarce as hens' teeth, I'd say
I think your terminology may be confusing the matter. It sounds like you are talking about content that was originally converted to i30 telecine then encoded as progressive with visible combing in the progressive frames? HandBrake would treat this the same as i30.markfilipak wrote: ↑Sat Sep 14, 2019 12:24 am Hey, John,
p30-telecine is rare -- I've only run across one -- but if the need arises and the source is known to originate from 24fps, how can I convert it to p24? I assume I would need to split fields to i30 first. Is that best done by directly invoking ffmpeg? Would I need to do the whole p30-telecine --> i30-telecine --> p24 via ffmpeg or is there a way to do a 2-stage process like that with HB?
Gee, I hope not. Names matter. I needed to differentiate a 30fps stream that was derived from p24 (i.e., temporal frames) from a 30fps stream that was derived from camera (i.e., temporal fields), so I call the former "i30-telecine" (or "p30-telecine") and left the later as "i30" (or "p30"), though, for the later, I also favor the terms "i30-telecast" (or "p30-telecast").JohnAStebbins wrote: ↑Sat Sep 14, 2019 3:43 pmI think your terminology may be confusing the matter.markfilipak wrote: ↑Sat Sep 14, 2019 12:24 am Hey, John,
p30-telecine is rare -- I've only run across one -- but if the need arises and the source is known to originate from 24fps, how can I convert it to p24? I assume I would need to split fields to i30 first. Is that best done by directly invoking ffmpeg? Would I need to do the whole p30-telecine --> i30-telecine --> p24 via ffmpeg or is there a way to do a 2-stage process like that with HB?
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i30 = [A][a][B][b][C][c][D][d][E][e] ...out of an NTSC camera
i30-bottom = [a][A][b][B][c][C][d][D][e][E]
p30 = [A/a][B/b][C/c][D/d][E/e]
i30-telecine = [A][a][B][b][B][c][C][d][D][d] ...telecined from p24 movie film samples
i30-telecine-bottom = [a][A][b][B][b][C][c][D][d][D] ...no sane video engineer would do this
p30-telecine = [A/a][B/b][B/c][C/d][D/d] ...rare, occasionally encountered
p24 = [A/a][B/b][C/c][D/d]
How does p24 become p30-telecine? I don't know. I imagine that telecine is accomplished as you suggest:It sounds like you are talking about content that was originally converted to i30 telecine then encoded as progressive with visible combing in the progressive frames?
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[A/a][B/b][C/c][D/d] --> [A][a][B][b][C][c][D][d] --> [A][a][B][b][B][c][C][d][D][d] --> [A/a][B/b][B/c][C/d][D/d]
I'm going to repond further down (i.e., not at this point) in order to address your next, very important statement.HandBrake would treat this the same as i30.
I'm glad you mentioned that. It brings up a point of unsurity for me. Do the HB devs considerThe decoding process is the same for both progressive and interlaced content. HandBrake receives full frames from the decoder.
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[A/a][B/b][B/c][C/d][D/d]
Well, you see, that statement cannot be fully correct. I intend no offense -- I have utmost respect for you -- and I'm not nit-picking. The combing isn't caused by the presence of interlaced fields, per se. It's caused by the 2-3 pull-down that's employed during telecine.In the case of interlaced content, there is combing visible in the frame due to the interlaced fields in the frame.
Do professional studio engineers make unrecoverable mastering mistakes when authoring DBs & DVDs? Sure they do. I could cite some examples. They sometimes make mistakes, and those mistakes make detelecining that content impossible and make the result worse than the source (e.g., really, really bad combing). Did those engineers make their mistakes because they were 'wiring' filter stacks via library calls without a clear vision regarding the underlaying, real video effects of those library calls? I suspect so. Did their lack of vision result from misunderstanding caused by poor terminology? I think so.The decoder also supplies flags to indicate that there are interlaced fields present, but HandBrake only uses these flags for handling soft telecine. In essence, what HandBrake sees for both interlaced and hard telecined content is a progressive frame in structure which has combing artefacts. The detelecine algroithm will remove the combing without loss of quality for hard telecine and the deinterlace algorithm will remove the combining with loss of quality (and loss of temporal information if the input frame was telecine).
I assume you mean HB treats p30-telecined sources & i30-telecined sources the same way? Can you be more specific? Since I have been led to believe that HB only does detelecine (not telecine), I'm unsure how to interpret what you wrote. ...Or, if I specify a 30fps target, does HB also telecine? ... Never mind, I can run an experiment to determine that.HandBrake would treat this the same as i30.
I see the change around 2002. I've always attibuted the improved resolution of newer DVDs to higher res sampling (i.e., for BD ... Nyquist and all that you know), but I guess lower compression enabled by improved storage utiization enters into it, too. Thanks for the insight.
Only when they want to be helped.markfilipak wrote: ↑Mon Sep 16, 2019 2:05 ammusicvid, you crack me up. Do you do a lot of work for amateur authors?
Oh, sorry. I thought you did commercial work.musicvid wrote: ↑Mon Sep 16, 2019 2:34 pmOnly when they want to be helped.markfilipak wrote: ↑Mon Sep 16, 2019 2:05 ammusicvid, you crack me up. Do you do a lot of work for amateur authors?
Yes. And you?markfilipak wrote: ↑Mon Sep 16, 2019 2:57 pmOh, sorry. I thought you did commercial work.musicvid wrote: ↑Mon Sep 16, 2019 2:34 pmOnly when they want to be helped.markfilipak wrote: ↑Mon Sep 16, 2019 2:05 ammusicvid, you crack me up. Do you do a lot of work for amateur authors?
I'm retired from circuit & chip design.musicvid wrote: ↑Mon Sep 16, 2019 3:32 pmYes. And you?markfilipak wrote: ↑Mon Sep 16, 2019 2:57 pmOh, sorry. I thought you did commercial work.musicvid wrote: ↑Mon Sep 16, 2019 2:34 pmOnly when they want to be helped.markfilipak wrote: ↑Mon Sep 16, 2019 2:05 ammusicvid, you crack me up. Do you do a lot of work for amateur authors?
I don't know. I block google and google owns youtube, so youtube doesn't play for me.musicvid wrote: ↑Sun Sep 15, 2019 7:08 am Pardon my naivete. I may have figured out your verbiage.
Is this what you're talking about?
https://www.youtube.com/watch?v=vJuSFUc1FYM
I can't see it. I block amazon, too.As in "formerly" telecine as processed by YouTube? I just helped a guy through this archiving puzzle (sans moniker) in February, using Handbrake.
Turns out Handbrake already deconstructs these fourth-generation abominations (aka "Frankenfiles") perfectly, at least as far as can be physically salvaged. I can show you how if you like.
https://s3.eu-central-1.amazonaws.com/l ... ED4055.mp4
They must be using google spyware too. I can't play that either.
Did you ever see the Star Trek TNG episode "Darmok"? You're really from planet Tamaria, aren't you?Tempest in a teacup.