field setting, a nightmare!

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Level 1

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field setting, a nightmare!

Here is my problem:

I got a video file in NTSC progressive no compression 8bit (3D animation), that was converted by a video conversion company to PAL lower field no compression 8bit. The point is to edit the PAL file in finalcutpro and get a DVD in PAL and a betacam tape in PAL.

1st problem: FinalCutpro says the NTSC file is lower field and compressor says it is progressive. I don't understand why Finalcutpro gets it wrong?

2nd problem: FinalCutpro says the PAL file is upper field and compressor says it is lower field, again FCP gets it wrong?

3rd problem: I actually asked the conversion company to put the file in lower field because I need at some point to do a DVD (DV-PAL), so I was thinking it would be easier to work in lower field only because DV-PAL is lower field. But I guess it was a bad idea because the PAL file they gave me is flickering on a TV screen, and if I use the filter that inverse the fields it gets back to a nice smooth movement. Which makes me think that they did something strange with the fields, they probable created a file in upperfield and then just inversed the fields?

4th problem: When you put a file onto a betacam tape, does the field has to be upperfield or can it be lowerfield or even progressiv?

5th problem: The original NTSC file is progressiv. Would it be a good idea to keep working in progressiv? Or will I loose some quality? I ask this because when the NTSC file was converted to PAL it wasn't progressiv anymore, so if I convert the PAL file to progressiv, I might loose some information?

6th problem: Just tell me in which field should be my project! I just realised that the setting no compression 8bit is by default in upperfield! So maybe that is the best way to go, to export to a betacam and then convert my final edit to lowerfield for the DVD (dv-pal) ?

As you can see I don't know much about fields, but I'm learning. I hope someone can help me on at least one of my questions

Thanks

Louie

PowerBook G4, Mac OS X (10.4.9), Final Cut Pro 5.1.4

Posted on Mar 20, 2007 4:27 PM

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Answer 1

tallguy

Level 4

1,415 points

Mar 20, 2007 4:44 PM in response to Louie13

typically ntsc 8 bit field dominance is lower. I'm curious as to where you got a progressive NTSC file. NTSC is interlaced.

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Answer 2

Louie13 Author

Level 1

0 points

Mar 20, 2007 4:54 PM in response to tallguy

Well the NTSC fiel comes from the US, but that is all I know and I'm not in contact with the people who did the file. The file could be corrupted... Compressor says it is progressive and the conversion company told me as well that it is progressive. And finalcut says it is lowerfield. I don't know who is wrong... And I think as well that it is strange...

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Answer 3

Mar 20, 2007 5:38 PM in response to Louie13

Where exactly are you reading the field data from in Final Cut and in Compressor? What window are you referencing to get your information?

What format is the file currently in (.mov, .avi, .m2v, etc.)? Since you have Compressor you can convert the file yourself from PAL to NTSC or from NTSC to PAL.

Ryan

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Answer 4

Louie13 Author

Level 1

0 points

Mar 20, 2007 6:04 PM in response to Studio006

My computer is in french language, but if I translate wright: in final cut, I see the field data in the window called Browser (in french "navigateur") and in compressor I see it in the window called Inspector (in french "Inspecteur").

All the files I'm refering to are in .mov

And yes, I know I can convert the file myself in compressor, the only problem is that it takes a hudge time to do it if I want to have the best quality conversion (with all the maximum quality settings, I get 40hours, and I have 2 files to convert actually). And while doing loads of test, I got a few times interferences (stranges pixels on one frame) and I can't afford to wait 40hours and have to do it again... I tried as well the natress plugin and it did the conversion well to a dv-pal format, but when I tried to do it to a pal nocompression 8bit, I got interferences even worse then compressor.....

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Answer 5

Mar 20, 2007 7:36 PM in response to Louie13

I don't understand all the above, but here are a few things I claim to understand.

Yes, NTSC can be effectively progressive. All that means is that both fields represent the same point in time. A shutter speed of 1/30 gives you progressive NTSC; same with PAL at 1/25.

If it came from tape that way, neither FCP nor Compressor would have any way to know. And even if the file identifies itself as progressive, that doesn't mean the contents are progressive.

If it is progressive then any issues with field order would show up as jaggies on any diagonal lines. If you see more jaggies with motion frames, then it is interlaced.

If it is progressive NTSC, then a clean PAL version will be much more difficult to produce. Temporal information is missing that would make the transitions smoother.

If you have permission to use this file, it surprises me that you don't have contact with the producer. I bring this up because you say it is animation. The producer likely has the means to make a clean PAL version of the animation very easily.

If you are going to do the conversion (and it is progressive), expect very juddery results in PAL. And absolutely do the editing in NTSC first, converting the final product to PAL. Otherwise you will get flash fields here and there next to edit points.

And finally, since the result in PAL (from progressive NTSC will probably be lousy, consider distributing it as NTSC. NTSC DVDs play fine just about anywhere the world.

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Answer 6

Louie13 Author

Level 1

0 points

Mar 21, 2007 6:23 AM in response to Steve Braker

First thanks a lot for helping me to understand something in all this confusion.

I have complete permission to use the file, the reason why I can't contact the people that created the file is that it went between several people in between. It would have been easier if they asked the original creators of the file to do the editing they want me to do. But it is cheaper for them to ask someone with less experience. And it would be even more complecated and time consuming for me to go through all the people and have a new file send from the US.

I'm a little confused with your advice to work in NTSC for the editing. The problem is that I have to mix it with pal footage and I have to give 8 different version of the final edit. So converting 8 files from NTSC to PAL seams more complicated then converting one file. I haven't noticed yet any flash field, but I gess I don't know what it really means...

And according to your comments I'm not shure if the NTSC file is really in progressive or interlaced. I'm startint to think it is interlaced. What I can see is that the movements are smooth, and when I did a few tests I meanged to convert it in DV-PAL with compressor and it created a lowerfield file with smooth movement. And the file I got from the conversion company in uncompressd 8bit is supposed to be lowerfield but it plays jaggie and when I inverse the fields it plays very smooth.

But I realised one point, maybe it is normal but I'm not shure: when I pause on the NTSC file and look on a TV monitor, every frame is nice and still, but with all the files in PAL from my tests or from the conversion company, I see on some frames with quick movements the frame flashing between to images. I gess it is because those files are interlaced, but then it could mean that the NTSC file is progressive?

About producing a NTSC DVD, the problem is that I have to produce PAL files, it is in the original brief. I'm stuck on that point.

So I'm trying to do the best I can with the material I got the quickest way I can, and use the PAL file I got from the conversion company...

But could someone tell me what field has to be used for a file (in uncompressed 8bit PAL) to be put on a beta tape? I gess I will start from there and try to use the filter that inverses the field when needed...

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Answer 7

Mar 21, 2007 7:48 AM in response to Louie13

The problem is that I have to mix it with pal footage and I have to give 8 different version of the final edit.

OK, we didn't know that. So yes, what you're doing is right: standards conversion before editing.

...the file I got from the conversion company in uncompressd 8bit is supposed to be lowerfield but it plays jaggie and when I inverse the fields it plays very smooth.

This says to me that the file from the conversion company is interlaced PAL, which should give you the best quality (though either they or you made an error with the field order). Your conversion may be just as good or better.

...when I pause on the NTSC file and look on a TV monitor, every frame is nice and still, but with all the files in PAL from my tests or from the conversion company, I see on some frames with quick movements the frame flashing between to images.

That pretty much says that the NTSC file was progressive. And going to intyerlaced PAL as you have in both cases will give you the cleanest result. You can just pick whichever conversion looks best to you (on a CRT monitor, though!).

But could someone tell me what field has to be used
for a file (in uncompressed 8bit PAL) to be put on a
beta tape? I gess I will start from there and try to
use the filter that inverses the field when needed...

Nobody ever understands this stuff well enough to tell anyone else, as "field dominance" doesn't always mean the same as "field order". I think the easiest thing to do is exactly what you did: do it one way, and if it comes out wrong do it the other way.(!).

Sounds like you've done all the right things. Are there still problems?

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Answer 8

Louie13 Author

Level 1

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Mar 22, 2007 7:44 AM in response to Steve Braker

Hello Steve,

Thanks a lot for your comments and help.

I finally did as I said. I put the PAL lowerfield file in an unpperfield sequence and used the filter to inverse the fields. I think the result looks great, but I haven't send it yet to be put on a beta tape.

But I must admit that I still have little worries about field:

I usually work completly in DV-PAL so the format uncompressed 8bit and the beta tape is all new to me. All the file I got in uncompressed 8bit (upper or lowerfield) have these thin lines on quick movements when I play the file in quicktime. I guess it is normal and is due to the interlace field. On a TV it flickers between 2 images instead of showing those lines.
In my experience of DV-PAL I never see those lines in quicktime.

My concern is now for making a DVD with iDVD.
If I export the uncompressed 8bit file to DV-PAL format and then put it in my iDVD project, there is no lines but I lost a lot of quality in the process. If I put directly the uncompressed 8bit file in iDVD I get a high quality image but I see those thin lines appearing when I play the DVD.

Do you have any suggestions to get high quality without those lines? I know that I could use the desinterlace filter, but this would simply erase one field and make the movements less smooth. And I find it strange that a DV-PAL file doesn't show these lines although it is interlaced as well?

As you can see my long adventures with fields isn't completly over...

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Answer 9

Mar 22, 2007 9:24 AM in response to Louie13

It sounds like you still have a field problem with the output to DVD.

First, don't bother going to DV. It will trash your video. So it's interesting to know that the results are different, but it doesn't help the product.

Second, I don't recommend iDVD for compression because you are left with no control over the process. If you need to use iDVD then I believe you can do the MPEG2 compression in Compressor and feed that to iDVD.

Third... assuming you need to keep your iDVD process, you need to either reverse the fields when outputting for DVD, or you need to undo filed reversal if you already did it.

Assuming field order is your problem. I can't tell from here.

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