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Roberto Serrini
23.98 footage - layed off on D5 - now interlaced? Whats this all about?
on May 6, 2010 at 9:20:15 pm

I have tried to piece together what exactly is happening here with bits of info from here and there...

We cut a project in 1920x1080 23.98 (FCP)

We gave this to a Flame Artist to conform. He laid it off to D5 for Broadcast. He then gave us back a 29.97 quicktime of the conformed spot.

HERES THE RUB: The quicktime has an obvious 2:3 pulldown. The 3rd and 4th frames are interlaced. It's totally noticeable in QT, noticeable in FCP. He says that on the HD D5 master it will play fine, because it will be playing on an NTSC TV, not a progressive monitor like we have hooked up to our MACs.

Can someone explain to me what exactly Im looking at, and why it would play back normally on an NTSC monitor but have a pulldown in QT? If its an interlaced signal, that is to say 59.94 fields a second, why wouldnt you just dupe the frames for the extra fields, instead of interlacing two different frames?

I feel like Im taking crazy pills. All help is appreciated. Thanks.


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Shane Ross
Re: 23.98 footage - layed off on D5 - now interlaced? Whats this all about?
on May 6, 2010 at 9:41:15 pm

Computer display are progressive only. They will not display interlacing properly. And 29.97 is interlaced. TVs, HDTVs, broadcast monitors...all display interlacing properly, so if you had a capture card on your system, and output that to a TV or monitor, then it'd look fine. But on a computer display...it won't look right. Because it can't show the interlacing properly. Wait, I just said that.


Shane



GETTING ORGANIZED WITH FINAL CUT PRO DVD...don't miss it.
Read my blog, Little Frog in High Def


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Dave LaRonde
Re: 23.98 footage - layed off on D5 - now interlaced? Whats this all about?
on May 6, 2010 at 10:22:52 pm

Ever watch a movie on TV? Movies are shot at 24 frames/sec, right? But TV is 29.97 frames/sec, right? So to get things to work out, they add 3:2 pulldown. Do movies on TV bother you? Didn't think so.

Your 24p epic was prepared for broadcast. That's 29.97 frames/sec. So they added 3:2 pulldown. Go burn that 29.97 Quicktime of yours to a 29.97 DVD, and watch it on a TV set. I bet it doesn't bother you.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Roberto Serrini
Re: 23.98 footage - layed off on D5 - now interlaced? Whats this all about?
on May 6, 2010 at 10:44:42 pm

thanks guys, really -

what I really didnt understand is how the D5 and subsequently broadcast transmission of the cut, made the interlacing work on a ntsc tv, because God knows if I saw the Quicktime version of it on my TV i would notice it looked like garbage.

You can totally see the interlacing fields not only when its playing down, but if you go frame by frame they are wicked evident.

I just dont understand how that translates on a D5 so that when it hits the tv you dont notice the pulldown or interlace frames.

Serrini
Director/Editor
http://www.robertoserrini.com




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Shane Ross
Re: 23.98 footage - layed off on D5 - now interlaced? Whats this all about?
on May 6, 2010 at 10:50:29 pm

[Roberto Serrini] "because God knows if I saw the Quicktime version of it on my TV i would notice it looked like garbage. "

No, you wouldn't. Did you gloss over the part where I said that computer displays don't show interlacing properly? That if you took the QT into FCP, played out via a capture card to a TV that it would look normal? Obviously you missed that.

[Roberto Serrini] "You can totally see the interlacing fields not only when its playing down, but if you go frame by frame they are wicked evident. "

Because computer displays are progressive ONLY and can't show interlacing properly.

[Roberto Serrini] "I just dont understand how that translates on a D5 so that when it hits the tv you dont notice the pulldown or interlace frames. "

Because the image from the D5 (well, what the network takes and compresses from that) will be playing on your TELEVISION SET...which is designed to show interlacing properly. Even HDTVs do this. But the QT, played on your computer display, will not show interlacing properly.

Have I said it enough?


Shane



GETTING ORGANIZED WITH FINAL CUT PRO DVD...don't miss it.
Read my blog, Little Frog in High Def


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Roberto Serrini
Re: 23.98 footage - layed off on D5 - now interlaced? Whats this all about?
on May 7, 2010 at 2:48:44 am

oh man. Shane... what is your deal? Did I insult you? did you invent interlacing? the NTSC standard? I mean why are you on my case? I've posted here a hundred times before and never has someone attack my post like you?

I never gloss over any advice anyone gives me, good or bad. What YOU failed to see was what I actually said. If I saw on a TV what I saw in the quicktime I would notice. Thats what I said champ.

Do you need to say more? Yeah chief, you do. You seem pretty smug with your knowledge of D5/interlace/NTSC standards, so why dont you tell me what Im asking:

how is it, that a 29.97 quicktime out of a flame, that was laid off to d5 for broadcast, would play back on air, to a television, without interlace? you failed to mention that Mr. "have I said enough". And dont say "I wouldnt notice." If you're an editor, and its your cut, you notice interlace, even in a single frame.

Im coming here with an honest question. For me, it doesnt make sense that a quicktime would show two of each five frames as interlaced, and that, somehow, gets fixed through broadcast transmissions. I understand that computer monitors are progressive and dont display interlace properly, as I said that in the original post. I also understand that the layoff will play properly on broadcast tv, HD or otherwise, as I said that in my original post. What I want to know is WHY? how does broadcast split fields, and why does a computer monitor only show two fields interlaced.

Say some more if you can. I gladly welcome your knowledge.

Serrini
Director/Editor
http://www.robertoserrini.com




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Shane Ross
Re: 23.98 footage - layed off on D5 - now interlaced? Whats this all about?
on May 7, 2010 at 4:23:43 am

Sorry, but I didn't think you wanted to go into the highly technical details of how TVs work opposed to how computer monitors work. Is that what you want to know? How a show that was shot and edited 23.98 progressive, now became 29.97 interlaced, and how that could possibly look good on a TV? Yet the 29.97 QT doesn't look good on the computer monitor? So you won't be satisfied with "That is how TVs and broadcast monitors are designed, and how computer displays are designed?"

Well, I am not an engineer. I know about interlacing, that was part of my school training. For that you can go here:

http://en.wikipedia.org/wiki/Interlacing

Why computer displays read this:

http://en.wikipedia.org/wiki/Computer_display

[Roberto Serrini] "What YOU failed to see was what I actually said. If I saw on a TV what I saw in the quicktime I would notice."

You won't. Computer displays don't show proper interlacing, so they show both fields at once...mashed up. Whereas TVs will show you both fields properly. HOW? I don't know, I am not an engineer, I am a creative editor. I don't need to know this stuff...I just need to know "that's how TVs work, and that's how computer displays work."

[Roberto Serrini] "how is it, that a 29.97 quicktime out of a flame, that was laid off to d5 for broadcast, would play back on air, to a television, without interlace?"

It doesn't. TVs play back interlaced. So they play the interlaced image properly. HOW does 23.98 get converted to 29.97 and look right? Well, that goes back to scanning film that ran at 24fps onto video tape at 29.97 fps. That is called 3:2 pulldown...

http://en.wikipedia.org/wiki/3:2_pulldown#3:2_pulldown

[Roberto Serrini] "f you're an editor, and its your cut, you notice interlace, even in a single frame."

ON my computer display...yeah, I see it. Not in FCP, FCP (and Avid) only play one field, not both. So you won't see that interlacing on most of the footage. But on the external monitor that I have connected via a capture card, I see the interlacing...properly. When I pause I see both fields, and when I play it looks normal.

[Roberto Serrini] "For me, it doesnt make sense that a quicktime would show two of each five frames as interlaced, and that, somehow, gets fixed through broadcast transmissions. "

That's part of the 2:3 pulldown. Part of one frame is in field one, and part of another frame is in field 2...of a frame. It has to make up 6 frames per second (24fps to 30fps), so it makes extra fields and mixes them. As explained in the TELECINE link I posted from WIKIPEDIA. And since the QT is playing on a computer display that doesn't show interlacing properly...you see that...garbled gook. It is fixed in the transmission...well, no, it is fixed in the TV receiving the transmission...in that the TV displays the interlacing properly.

[Roberto Serrini] "What I want to know is WHY? how does broadcast split fields, and why does a computer monitor only show two fields interlaced.
"


Read the links provided. And pardon my snarkiness. I forget that people like to get into the nitty gritty of the technical stuff from time to time. And I already learned it, and it makes my head hurt. I just wish I knew "This doesn't do it right, and that does."



Shane



GETTING ORGANIZED WITH FINAL CUT PRO DVD...don't miss it.
Read my blog, Little Frog in High Def


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Bret Williams
Re: 23.98 footage - layed off on D5 - now interlaced? Whats this all about?
on May 7, 2010 at 6:35:32 am

Let me try-

Anything played on a NTSC TV gets displayed interlaced. 60 fields per second. Regardless of how it was shot. A tv will play back the odd lines of an image, then the even ones. So, the 24 frames a second has to become 30. Essentially means repeating every 4th frame. Now, since a TV has 60 images to build off of, it is MUCH smoother to utilize them. If you jus repeat the 2 fields of the 4th frame, you\'re going to have a stark pause in the action that is very noticeable in faster motion like pans or cars, etc. To create 5 frames where there were previously 4, pulldown leaves frames 1 and 2 intact. Then frame 3 is a blend of frame 2 and 3. Frame 4 is a blend of 3 and 4. And frame 5 is the original frame 4 intact. So, in the interlaced world, you now have 5 frames, each with 2 fields and none of them represent the EXACT same moment In time. The above is the smoothest pulldown. You can also just have a new frame created that is a field from the previous frame and a field from the upcoming frame. I think that is what happens when you shoot 24pA or is it N? Obviously just blending one frame means spreading out less fields less frequently and would look closer to just repeating a frame. The benefit is that the newly created frame is easily removed, restoring the original 24p progressive sequence. Great for going back to film or for burning DVDs. What? A DVD player can play back 24p to a regular NTSC screen? Yes. It was part of the DVD player spec from the beginning that DVD players have the ability to add pulldown on the fly through hardware.

What\'s a progressive scan DVD player? With the advent of LCD tvs, LCDs were able to play at multiple frame rates. So via the component output of a progressive scan DVD player you can actually play 24 progressive non interlaced, pulldown free frames per second like in a theater.



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gary adcock
Re: 23.98 footage - layed off on D5 - now interlaced? Whats this all about?
on May 7, 2010 at 1:18:21 pm

[Roberto Serrini] "What YOU failed to see was what I actually said. If I saw on a TV what I saw in the quicktime I would notice. Thats what I said champ. "

Roberto.
I guess I am with Shane on this. These are really basic concepts regarding video production that have been covered a couple of dozen times this week alone.

I did not see Shane's response as anything expecting you to have a certain knowledge based on the level of gear you are commenting on working with.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows for the Digitally Inclined
Chicago, IL

http://blogs.creativecow.net/24640



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John Heagy
Re: 23.98 footage - layed off on D5 - now interlaced? Whats this all about?
on May 7, 2010 at 2:19:38 pm

Yes I agree, this is Video 101. Shane was clearly frustrated, and I feel his pain.

Shane is owed a big thanks for taking considerable time to explain this basic concept.

John Heagy
NFL Films


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Roberto Serrini
Re: 23.98 footage - layed off on D5 - now interlaced? Whats this all about?
on May 7, 2010 at 2:27:10 pm

Thanks for the info Shane - I appreciate you getting into it.

Serrini
Director/Editor
http://www.robertoserrini.com




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cowcowcowcowcow
Dave LaRonde
Re: 23.98 footage - layed off on D5 - now interlaced? Whats this all about?
on May 7, 2010 at 3:13:59 pm

Just for the heck of it, I looked your many professional qualifications in the "About" section of your web site.

I confess am profoundly surprised -- dumbfounded may be more accurate -- that you somehow missed learning a concept as fundamental as 3:2 pulldown as it is displayed on video monitors and computer monitors.

You are, after all, reputed to be "Apple certified in FCP", to say nothing of "able to work with every codec in existence"... which implies work in SD codecs such as DV 25 and DVCPro 50, both of which most certainly contain interlacing, and both of which you certainly must used in the past.

My sincere hope is that this brief foray into the pedestrian world of broadcast reality has now filled in that one tiny gap in your vast experience. May you enjoy continued success.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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cowcowcow
Roberto Serrini
Re: 23.98 footage - layed off on D5 - now interlaced? Whats this all about?
on May 7, 2010 at 3:17:39 pm

You got me. Im a fraud. Shit, I knew that online college course was too good to be true.

Thanks for your help.

Serrini
Director/Editor
http://www.robertoserrini.com




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