Big Problem: 2 frames interlaced, no 3:2..!!!

Having a crisis with interlacing. 16mm film x-fer digibeta, shot 24 fps. Avid system confirms 3:2 pulldown but FCP system shows 2 frames with split fields (field order) not the pulldown frames. All of the projects with this issue originated on an Avid, exported AAF (no media) and recaptured to FCP timeline for online/color correction.

We see this on everything on the FCP systems, original scenes, round trip renders through Shake and Color. Picks up frame blending when coming from color (not de-interlaced) shows up as a shadow image to movement. Seen on export of QT from FCP and only disappears with de-interlacing which softens the image on some clips, distorts others.

Everything within the system is set to lower field dominance. Capture settings, clip settings, timeline settings. We have tried switching field orders and on some clips the interlacing disappears.

We digitize via a Phillips router for machine control and SDI from a remote VTR.

I have never seen this before on film transfer footage in FCP, I hope its a simple solution right in front of me. Thanks in advance for helpful thoughts.

2 x 3.2 GHz Quad-Core Intel Xeon 8 GB 800 MHz, Mac OS X (10.5.5), Kona 3, XServe RAID

Posted on Feb 6, 2009 2:44 PM

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23 replies

Feb 6, 2009 3:31 PM in response to Patrick Sheffield

Let me clarify. This is 29.97 fps 601 video coming from a Digibeta to FCP via a Kona 3 and a Phillips router. The tape is a film transfer. The pulldown is in the footage added by the tele-cine. FCP will not see the frames with the pulldown. Why would I need to remove the pulldown, I am digitizing at 29.97 and outputting at 29.97?

I'm not certain the pulldown frames are the interlaced frames but it sure sounds like it.

Feb 6, 2009 3:48 PM in response to Patrick Sheffield

Exactly, why wouldn't we see the frames?

We can't see the duplicated pull-down frames, we see 2 frames (not repeated) with the wrong fields together, then normal frames. We see this on the digitized clips and exports. Our house Avid sees the pulldown frames as they should be on tape, what is the difference might be the question? Or, is this a house sync delay issue or problem with our VTR?

Also when slowly jogging though the digibeta, we don't seem to see the proper pulldown either, but the Avid can digitize and see the pulldown. Any thoughts?

Feb 6, 2009 4:07 PM in response to avideditor

Pulldown frames ARE interlaced. They are not a repeated frame - that would look stuttery on video. They are a field of the last frame and a field of the next frame. Or, more accurately, they look like this (thanks to Adam Wilt for the image):

User uploaded file

Perhaps you're misunderstanding what the Avid is showing you. Depending on the Avid, often they only show you one field and double it. So you would perceive of it as two of the same frame.

In FCP/Shake/Color, you are seeing just what's on tape - both fields.

make sense?

Patrick

User uploaded file

Feb 6, 2009 4:13 PM in response to Patrick Sheffield

Yes and helpful. What I must be further misunderstanding is why our renders from Color frame blend these fields together and yield a shadow image to areas of motion.

I feel like our system is not interpreting the field dominance correctly on some frames. Our quicktime exports look very interlaced on areas of motion while playing, like the dominance is inverted. On 29.97 fps video, all fields are interlaced and one field is different from the other yes? So why do I only see the zipper effect on two frames?

Our footage is being rejected by DG systems, only happens on this particular footage.

Sorry if this is basic, its been a long week.

Feb 7, 2009 7:45 AM in response to avideditor

Thanks to Patrick for trying to solve this issue, but I'm not sure if I am explaining our problem correctly. I have worked with lots of film transfer footage on FCP in other facilities and never seen this issue. If anyone else has a good idea of what I am describing and has any helpful ideas, my thanks in advance.

Here is a basic question to start with.... If our footage is 29.97, from Digital Betacam, digitized at 29.97, and it has 3:2 pulldown, when I de-interlaced the footage would I not see 2 repeated frames of video?

If the answer is yes then that might reveal our problem because we do not see this at all.

Feb 7, 2009 11:05 AM in response to avideditor

It sounds like it's working as it is supposed to. Obviously you had to add the telecine to get it on the tape, but at this point, if it's a true telecine, you can remove the pulldown on capture, or after using Cinema Tools and edit in 23.98... That is a better way to go. Once you start editing in 29.97 you'll be stuck there for the duration. If you're going to DVD, the DVD player will add the pulldown on the fly, so you don't need to edit and master in 29.97.

Feb 7, 2009 12:45 PM in response to avideditor

Oh, I think I understand the situation pretty well. I've dealt with pulldown enough over the years to recognize it.

As redtruck says - unless you're removing the pulldown, you will be dealing with interlaced pulldown frames. And unless the software you're using knows it's dealing with interlaced frames, you can get mushy frames as the two fields get averaged thru processing.

A quick perusal of the Color forum produced this post with tips for dealing with field problems in Color.

http://discussions.apple.com/thread.jspa?threadID=1893048&tstart=0

One thing to note - before you send to Color, DO NOT resize or reframe your shots. Do that after you get it back from Color.

Patrick

User uploaded file

Feb 7, 2009 1:11 PM in response to RedTruck

Obviously you had to add the telecine to get it on the tape, but at this point, if it's a true telecine, you can remove the pulldown on capture, or after using Cinema Tools and edit in 23.98... That is a better way to go. Once you start editing in 29.97 you'll be stuck there for the duration. If you're going to DVD, the DVD player will add the pulldown on the fly, so you don't need to edit and master in 29.97.


However, if they're delivering to DG Systems, that implies broadcast distribution. If that's the case and they've removed pulldown to edit in 23.97, they need to add the pulldown BACK when they're done. (Seems everything I do these days gets sent to DG for distribution. It's been nearly a year since I actually put something back to tape. Its all MPEG Program Stream, then upload to DG.).

I don't generally remove pulldown from projects that come in with it - except on a shot by shot basis to do efx work. However, when I'm dealing with a 23.98 project (either because it originated on RED or P2) that will go to broadcast, I use Shake to add the pulldown back to the final piece after final grading and downconvert, but I dunno if they have Shake and I haven't been able to convince Compressor to add pulldown. It will remove pulldown, but it doesn't add it back.

Patrick

User uploaded file

Feb 7, 2009 1:29 PM in response to Patrick Sheffield

Our Kona 3 adds the pulldown back automatically if we layback to tape, which we are not doing. Having tested the DG delivery workflow, I can send a 23.98 QT file to Episode using the DG template and it delivers a 29.97 file. Nice. Also Cinema tools will add pulldown I believe.

But... if the pulldown interlaced frames are "normal" in FCP, and they continue to show up in the exported QT file and that is the cause for DG's rejection... does that mean that anything we finish in FCP has to be de-interlaced and/or have pulldown removed and finished 23.98? I'm all for that frame rate. I just know I have finished things (to tape) shot 24 fps on film and not seen these issues in a 29.97 environment before in FCP.

I can see this happening if the field dominance is inverted or set to none where is should be lower. Doesn't having all the same field dominance's set the same do the same thing as the Avid does when it views only 1 field? Isn't it about interpreting field order, like you do in Shake or AE?

Thanks for the link to the Color info, we had resized shots prior to Color in Shake, not FCP but I assume it's causing the same issues. I never would have imagined that all these problems would exist between these bundled software packages. It would be great to have these things talking to each other properly without knowing the secret handshakes.

One last thing... per my earlier simplified question... If we have pulldown and I de-interlace the shot, instead of seeing the interlaced pulldown frames, wouldn't I see two duplicated "frames" as I step through?

Feb 8, 2009 7:26 AM in response to avideditor

You Can in the Kona control panel pause on full frame or single field Kona control panel>Codec tab.
This may or may not help you see whatever issue you may be having.
one of the great things about these bundled apps is the ability to process footage multiple ways. In your avid you select your compression and away you go everything else is thought out for you. In the FCP package you really want to ask where am I going to end up, and how do I get there with what I have to start with. DG will tell you what they perceive as the problem. You don't have to do anything like deinterlacing or frame rate conversions to get stuff out to DG or tape. check the pulldown of your source stepping through a frame at a time with the kona paused on frame, viewing the Kona output on an NTSC monitor.

Feb 9, 2009 7:36 AM in response to avideditor

First off, I appreciate the helpful comments to date. I believe that I have come to the solution by information in the FCP manual, but I wonder who out there is working this way and how this impacts other simple FCP workflows. Responses are welcome.

Volume IV-170: "The telecine process adds duplicate video fields to make 24 fps film footage fit within 29.97 fps video. The film–to–NTSC video case is particularly complex: the film is slowed from 24 to 23.98 fps during the telecine process to match the discrepancy between 30 and 29.97 fps. Simultaneously, film frames are repeated in a 3:2 pattern, resulting in duplicate video fields. *Once your video footage is captured to disk, you need perform a reverse telecine operation to remove the 3:2 pull-down. You can perform the reverse telecine operation on media by choosing Tools > Cinema Tools Reverse Telecine."*

+FYI... In Avid it is not necessary to remove 3:2 pull-down just to edit, certainly if you were doing opticals, but not as standard workflow.+

Appendix C, p. 419: "If you edit 3:2 pull-down footage without removing the pull-down first, you need to be particularly careful to match the five-frame pull-down cadence at every edit. Edits with
broken cadence, such as a repeating or out-of-order frame (for example, A, B, A, B, C, D) can confuse reverse telecine operations. *In general, you should avoid editing 29.97 fps pull-down footage. Instead, remove the pull-down of your footage first, edit at 23.98 fps, then reinsert pull-down during output."*

Question: Is this the standard workflow for most people out there? Do you always remove 3:2 pulldown with Cinema Tools first and edit at 23.98?

Questions: What about digitizing pre-edited masters, that maybe came from other edit systems like Avid where you don't need to remove pull-down. In order to digitize a master and export a file from it, if that tape has pull-down footage within it, do you need to remove pulldown just to have it export properly? And if this master is mixed with pulldown and non pulldown footage?

Question: If I am recapturing clips from a project already edited in Avid @ 29.97 with out removing pulldown, how do I convert that into a timeline I can capture to in FCP with pulldown removed?

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Big Problem: 2 frames interlaced, no 3:2..!!!

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