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Stu Gilbert
projector wont deinterlace
on May 17, 2013 at 1:38:46 am

shot at 24p, edited in a 29.97 sequence, lower frame first.
exported w/ compressor, prores 422.

rented an optima th1020 projector for the screening (on monday). going through my laptop, dv to vga to projector. here is my problem- when I project it, its still interlaced

&*^^%%$!!!!

a friend suggested using VLC player, and turning the de-interlace filter on. I did that, and it does not help one iota. (see photo)


I know that it will look interlaced on a computer screen, I'm not concerned about that. I am concerned that seemingly nothing I do de-interlaces the projected image...

Right now, I'm de-interlacing w/ compressor, and since its a 45 minute film, thats taking some time.....

In the meantime, I wanted to pick the brains of all you knowledgeable folks here.... I know it can be done w/o deinterlacing in compressor...... but how?!!?!?!?!?


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Nick Meyers
Re: projector wont deinterlace
on May 17, 2013 at 2:00:00 am

in my part of the world we don't have to deal with pulldowns etc,
but could be that is your problem.

you have put 23.976 material into a 29.97 timeline,
isn't it the case that the fields get re-distributed,
and you will get blended frames?

can you not work in a 24p sequence?


nick


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Bret Williams
Re: projector wont deinterlace
on May 17, 2013 at 3:42:38 am

In FCP legacy, if you drop 24p into an interlaced sequence, it will not add interlaced pulldown. It just repeats every 4th frame. As well, in an interlaced sequence, progressive material will always still look progressive. Even if it's treating it as interlaced material, it is still impossibly to create fields where there are none. IOW, the field order won't even matter as both fields are exactly the same.

If you shot 24p, and you want to use it in a 30fps sequence, you should add interlaced pulldown. That is what goes on on television and DVDs. Otherwise you'll get an odd stuttery cadence of every 4th frame repeating.

In FCP X if you drop 24p into a 30i sequence, it WILL add proper interlaced pulldown. (which will look like 3 progressive frames followed by 2 blended frames) But it is of course a newer app more in tune with modern technology and professional formats. I would donwload the trial of X, drop your 24p into a 30i sequence and press export and you'll have yourself a broadcast ready interlaced hd file in no time at all that has the proper interlaced pulldown and cadence.

But if you don't want to do that, why not just drop the 24p into a 30p sequence and see if the cadence is acceptable. If there's not too much panning it very often is.

There is no reason to be deinterlacing anything as you don't have anything to deinterlace. That's why you haven't seen any difference with any deinterlacing tools.


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Bret Williams
Re: projector wont deinterlace
on May 17, 2013 at 3:54:11 am

Oh, wait... EDITED 24p in a 29.97i sequence at LOWER first? Assuming it's anything except a DV sequence, then it should be UPPER first.

So it's not really fields, but somehow it's playing the fields in reverse order for each frame, and pulling a field from the next or previous frame and mixing it with the current. Not interlacing, just kinda offsetting. That's all I can figure. Change the sequence to upper first and you might fix it. Or, like I said just change it to progressive because 7 can't add pulldown anyway.


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Stu Gilbert
Re: projector wont deinterlace
on May 17, 2013 at 3:56:43 am

Oh, sorry, should have mentioned..... it is just standard def DV, and (embarrassingly) I'm still on 6...


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Stu Gilbert
Re: projector wont deinterlace
on May 17, 2013 at 4:04:10 am

is it possible that switching from vga to hdmi would have any impact?


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Stu Gilbert
Re: projector wont deinterlace
on May 17, 2013 at 3:55:22 am

Bret- how would I go about adding interlaced pulldown?
(Unfortunately, when I started editing on all this, I was not made aware of the fact that I'd need to change sequence settings to edit progressive footage, so its not a matter of "wanting" to do a 30fps sequence, its a matter of thats was used.)

I do know that, somehow, it IS possible for this footage to be projected w/o those artifacts, whatever is causing them, w/ simply a prores export because it was done before. A shorter version of the project was shown w/ the same settings and looked fine (unfortunately, I cannot get ahold of the projectionist who did so).


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Bret Williams
Re: projector wont deinterlace
on May 17, 2013 at 4:28:51 am

If it was all shot 24p, you really should edit 24p. You can copy all the material and paste it into a 24p sequence. You're going to have all sorts of gaps and issues galore because of the rate difference. You'd have to manually go through and fix all the problems. But you'd have a proper 24p master for the web. And you could run that master through compressor to add the pulldown for a 30i version. FCP X is easier. Just drop it in a 30i timeline and export however.

Your best may be to just change your sequence to progressive and export. If that doesn't work, then it's definitely some sort of projector something.


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Stu Gilbert
Re: projector wont deinterlace
on May 17, 2013 at 4:34:32 am

just went and looked, and it does seem to have some kind of pulldown... definitely has the 3, 2 thing happening....
i'm sort of leaning towards a projector issue at this point..... which may be worse, really.


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Dave LaRonde
Re: projector wont deinterlace
on May 17, 2013 at 2:40:02 pm

[Bret Williams] "If it was all shot 24p, you really should edit 24p"

Amen to that! You'll probably have to remove the pulldown on INDIVIDUAL SHOTS, shot by shot.

The playback device being used also plays an EXTRMELY crucial role in good-looking playback. Unfortunately, we don't have that item of information. The projector isn't the playback device: it is the display device.

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


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Rafael Amador
Re: projector wont deinterlace
on May 17, 2013 at 2:17:04 am

Those are not interlacing artifacts.
[Stu Gilbert] "shot at 24p, edited in a 29.97 sequence, lower frame first."
If you shot Progressive, you have to edit Progressive.
I think you are creating those artifacts by treating Progressive stuff as Interlaced.
rafael


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Steve Eisen
Re: projector wont deinterlace
on May 17, 2013 at 4:33:50 am

If you want a little better quality playing your video to your projector, you should output your sequence to DV Tape. Use a DV deck and connect that to your projector.

Computer signal and video signal are VERY different.

Steve Eisen
Eisen Video Productions
Vice President
Chicago Creative Pro Users Group


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Rafael Amador
Re: projector wont deinterlace
on May 17, 2013 at 6:08:36 am

[Bret Williams] "Oh, wait... EDITED 24p in a 29.97i sequence at LOWER first? Assuming it's anything except a DV sequence, then it should be UPPER first. "
No if we are talking about SD.
Yes if is HD.

IMO the issue is for editing Progressive stuff as Interlaced.
Most of all if the original footage is 420.
When the footage is 420, the Chroma pattern is different for Progressive and Interlaced stuff.
rafael


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Simon Modery
Re: projector wont deinterlace
on May 17, 2013 at 8:12:29 am

Is the photo you posted turned by 90 degrees? Because if the lines really go vertical it can't be a de-interlacing issue (field lines are always horizontal).

Head of Postproduction
Motherlode

http://www.simonmodery.com


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Stu Gilbert
Re: projector wont deinterlace
on May 17, 2013 at 2:16:40 pm

yes, for some reason it is flipping it 90 degrees.....


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Rafael Amador
Re: projector wont deinterlace
on May 17, 2013 at 2:54:46 pm

Right.
Having another look, up to the position of the shirt pocket, seems that the picture has been flipped 90 degrees.
rafael


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Joseph Owens
Re: projector wont deinterlace
on May 17, 2013 at 3:49:39 pm

[Simon Modery] "Because if the lines really go vertical it can't be a de-interlacing issue (field lines are always horizontal)."

That's what is really fishy with this story. Those vertical lines really more resemble some kind of DV50 loss compression.

Unless your deliverable specifically requires a frame rate conversion, there is a reason why most, if not all, of those contracts specify that the edit be carried out in the source footage native frame rate and field dominance, if there is one. Dropping the (HD?) 24p footage onto an SD 2997 timeline is the straightest, most direct route to disaster that is possible to draw. 2:3 cadence depends on interlace to work, which is one of the reasons that it is such a total disaster in Final Cut Pro, up to Version 7. FCP simply can't do the math, because it is not field-aware.

Edit native: recompress and convert for final deliverable. In this case, the projector is finally revealing that there is a process problem.

One other issue that occurs to me is aspect ratio conversion -- if the original footage was 16x9, then it is being "anamorphasized" for the SD 4x3 native aspect ratio (I don't see letterbox being a factor here). There are issues with some format confusion between codecs making this conversion under some circumstances, and may be forcing a bad proxy render.

jPo

"I always pass on free advice -- its never of any use to me" Oscar Wilde.


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