Is it bad to mix interlaced and progressive in a progressive timeline?
May 30, 2010 05:30PM
Just curious your opinions. I have a bunch of 1080i material to go along along with the master 1080p material. Stylistically, we like the difference in cameras, however we need to decide whether to de-interlace at this point before final conform is sent off for color correct. We are sending the color place an uncompressed QT along with an EDL to establish cut points.

This is planned for film out. Just how bad will the interlacing look? We like the badness, as it is a dirty doc style, but we don't want to to look like a huge mistake either.

Noone has any experience with this sort of style that I know.
Re: Is it bad to mix interlaced and progressive in a progressive timeline?
May 30, 2010 06:30PM
If you (or more to the point, your director) likes it, then screw the rules.

Just send your 1080i60 material out to a post house and have it run through a Teranex for conversion to 1080p24 before you cut it in with the rest of your footage. In my opinion, none of the software frame-rate conversion options are acceptable on the big screen.

Re: Is it bad to mix interlaced and progressive in a progressive timeline?
May 30, 2010 07:33PM
This is more a theory then a FCP question, since the project is actually in Avid.

The way these other files were originally prepped shot on Canon Vixia 1080i 24p they were imported through FCP log n transfer at 29.97 ProRes422. Those files were then taken into compressor to remove pulldown, however interlacing was not removed at that time. So essentially now they exist as 23.98 1080p files at DNXHD115, with interlacing built in, then imported into an Avid 23.98 1080p project.

So basically now they have files that are 23.98 1080p, but still have the original interlacing built in. Budgets and conform ideas changed as time went on, and they really screwed themselves IMO. Now they are left with hundreds of these shots with interlacing. I could easily drop a fluidmorph de-interlace onto it, and render out, but at the same time they also like the look of this original interlaced material now. I just don't know how that would look when it gets big.
Re: Is it bad to mix interlaced and progressive in a progressive timeline?
May 30, 2010 09:25PM
Quote

Those files were then taken into compressor to remove pulldown, however interlacing was not removed at that time.

That kind of doesn't make any sense. Typo, maybe?

Quote

So basically now they have files that are 23.98 1080p, but still have the original interlacing built in.

Yeah, that's the part that's basically impossible. Have another crack at asking this question, 'cause I'm not understanding it so far.

Re: Is it bad to mix interlaced and progressive in a progressive timeline?
May 30, 2010 09:32PM
Me neither. Interlacing does not exist on 23.98fps or 24fps footage. There's no such thing as "24i".

So I'm taking a wild guess to say that when you removed the pulldown, it wasn't done right -- wrong pattern? The wrong fields were removed?

I don't know everything about every Canon Vixia model, but the one I have doesn't shoot true 24p. It tries to simulate the 24p look while recording at 29.97fps. It does a crappy job at it, in my opinion, and I don't think it follows the same rules as true 24p -- not even 24p DV footage, which still behaves exactly as traditional footage with 2:3 pulldown. I would suspect that also has something to do with your problem.

If I'm right, then importing those clips at 29.97fps was the right thing to do, but removing pulldown in Compressor wasn't, since the footage wasn't truly 24p.


www.derekmok.com
Re: Is it bad to mix interlaced and progressive in a progressive timeline?
May 30, 2010 10:32PM
Okay, so I think I have it figured out now that I'm going through Compressor settings.

So looking at the settings in compressor. It is going to 23.98 1080p DNXHD115. The frame control tabs have reverse telecine selected. I'm thinking this was really more of a straight frame rate conversion, versus any actual "reverse telecine" action taking place. I'm going to do a test to be sure. I didn't set it up, so I'm hunting it down.

So basically, if this were the case where it was simply a frame rate conversion, yes I would have interlaced looking 23.98 1080p material. It looks really decent so that is good.

Using de-interlace filters actually wipes out the scan lines, and looks pretty decent. So That is one option to fix.

The other option is to reimport all the files I need into FCP via L&T (since the original imports are long gone), and run those through compressor the same way, only de-interlacing at that point. I can leave it as 29.97 if I feel like over-cutting hundreds of shots in a week, or take it to 23.98 and batch import. Machine time vs. human time.

The last option being leaving the scan lines, and hope it looks decent. I just know they aren't paying me enough to deal with it.
So I've gotten to the bottom of it I think!
May 31, 2010 12:26AM
So definitely was a frame rate conversion with compressor, with the reverse telecine tab selected, which had no effect. So that is what threw me off.

I just did a couple of the files keeping frame rate conversion, and selecting the middle "better" de-interlacing setting, and actually encoding at dnxhd175 vs 115, and it imports perfectly. Problem is it takes roughly 8 times real time for the whole process, of L&T, compressor frame convert/deinterlace, re-import into avid for not much difference picture wise compared to letting Avid de-interlace the existing footage. There is a very small bump in sharpness going to the new file that of course makes sense.

I'm leaning towards going filter only though, as part of the "style" they are going for is for that footage to be distinctly poorer in quality compared to the XD hero cam, and they liked the look of it at half res viewing.

If it was hero type footage, I'd definitely do it, but it is roughly 10 hours and 191 clips! My poor Macbook Pro isn't exactly a powerhouse on transcodes. Maybe a new iMac i7 is in the cards. Nah... not worth spending the dinero. Thanks for helping me talk it through.
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