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Teranex Xantus and 3:2 pulldown


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#1 steve waschka

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Posted 23 June 2015 - 05:11 PM

Perry Paolantonio you may be the best resource for this. But, I tried to PM you and it wouldnt let me. I just converted an Eclair NPR to 30fps wild when it was 24fps sync to match +/- 30psf sd video. Then just saw an old BM forum post you wrote about the xantus and its 3:2 capabilities. Is it good enough for me to put the camera back to 24 sync and use the xantus? I have never used it for anything but video processing.


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#2 Robert Houllahan

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Posted 23 June 2015 - 09:54 PM

3:2 Pulldown is added in Telecine to 24 FPS Film to make it go into 30FPS interlaced video.

 

So the 3:2 part is video FIELDS and one frame of film goes into 2 fields (1 frame) then the next frame goes into 3 fields (1.5frames) then the next frame of film goes into 3 fields (the other .5 frame and the next frame) in an ever repeating 2:3:3:2 pattern.

 

If your camera was running at 30fps (matching the 30fps video) no pulldown would be applied and the film and video would have a 1:1 ratio.

 

The 30fps film is basically slow motion when played back at 24fps.


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#3 steve waschka

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Posted 23 June 2015 - 10:12 PM

I keep thinking there may be some magic in the xantus I am not taking advantage of when it comes to taking a telecined 24fps film on SD tape and outputting to 29.97psf. But I decided not to burn film and test it before converting this camera. Everything I have shot has been at 30fps. So I have no reel laying around to try it out. I guess I could send in an old print of something.


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#4 David Mullen ASC

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Posted 23 June 2015 - 10:22 PM

Are you aware that you can put 24P on a DVD or Blu-ray and the player adds the pulldown if necessary?  It's only SD tape-based storage that needs 60i, and who uses SD tape anymore?


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#5 Perry Paolantonio

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Posted 24 June 2015 - 07:19 AM

Hi Steve,

 

The Xantus (and other Teranex models) are designed to deal with the type of material that Rob describes: footage that originated as 24p but was encapulated in a 29.97i video signal (HD or SD). The way the machine works is to take an SDI or HDSDI video input, and if it detects pulldown, it removes it. In this way, any processing it may do internally (up/down conversions, noise reduction, aspect ratio conversion, etc). is all done on a progressive image, which gets you a better result and is easier to do. Then on the output side, the Teranex will let you either reconstruct the pulldown as it was, clean it if it's broken, or on some models just remove it and output a 24p signal. 

 

We bought ours several years ago to deal with the middle situation. What a lot of people don't realize is that if they transfer a film or 24p content to 29.97i with 3:2 pulldown, and *then* edit it further, they're breaking the pulldown pattern. The teranex detects and fixes these breaks in real time, and can then output a clean 29.97i signal with unbroken cadence. And it does an amazing job of it. We had masters that were impossible to make into progressive DVDs because of broken cadence (the encoder just couldn't keep up with the cadence breaks), but capturing it through the Teranex fixed it. 

 

 

You may be able to create a 24p output from the 30p footage, but I think it would depend on the model and the options installed. Also, it would either need to interpolate or simply drop frames to go from 30->24, so there will likely be some artifacting. 

 

@David Mullen: We still get a lot of HDCAM masters for Blu-ray that have 3:2 pulldown. Sometimes they're just several years old, sometimes they're made by facilities still doing telecine work to this format. But it's out there, in large numbers, even in HD. 

 

-perry


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#6 steve waschka

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Posted 24 June 2015 - 11:06 AM

Perry- I think I need to leave my film cameras at 30fps to match the video cameras. Because one video camera cannot do 24p. and the other one isnt any good at it unless you have the matching edit deck. I am not buying anymore edit decks.

 

David- I know its dinosaur. But I can do SD video well with what I have. I cannot do HD properly without major investments. And I have barely flexed the muscles of this equipment. If I need to do HD or 35mm I will have to rent and someone else is gonna have to pay.


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#7 David Mullen ASC

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Posted 24 June 2015 - 01:00 PM

Considering we've had video cameras that could do 24P for fifteen years now, and videotape has almost entirely disappeared, you really must be working with old gear.  I guess the question is why spend the money to shoot in 16mm film if only to finish to 60i SD videotape?  Particularly since you don't even have to work with videotape in post anymore, you could get your film footage delivered on hard drives as 24P (480, 720, 1080, etc.) and put it directly into your computer for editing, and release it in 24P on numerous platforms: DVD, blu-ray, Quicktime files online, etc.  I think it's probably time to retire your 60i camcorder if that's the one element holding you back.

 

Also, your 60i camcorder isn't shooting 30P so even if you run your film camera at 30 fps, it isn't a perfect match in look anyway, so what's wrong with 24 fps film with a 3:2 pulldown cut into a 60i project timeline?


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#8 steve waschka

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Posted 29 June 2015 - 09:40 PM

David: I am not certain 24p in a 3:2 will be an issue. And no the 60i camera' footage goes thru the teranex and converted to 29.97psf if going onto hard drive. When put into a 30p timeline the computer knows no different. However, the deinterlacing of the teranex does soften the image. So the camera's scope of use is somewhat limited to close shots. Even the 30p camera's image will be fairly soft on wider shots compared to film. So film will be my vehicle into HD. Honestly video, for me, was supposed to be the tool for interviews and sports footage where i had to take long runs to get the shot. When I started using it I had no idea how much tech I was going to have to learn. I guess the 2/3" prism block sensors becomes an acquired taste as the look grew on me. Although I hated the aliasing. The past few years have been testing of tons of deinterlacing programs and scripts, expensive filters, and modifying shot technique to limit it. I started using a standard 4:3 2/3" sensor and shooting anamorphic and widening with a scaler. Looked pretty cool but the footage was now in HD size. My MacBook pro choked on it. Couldnt edit it at all. Then I went to the widescreen sd cameras and things got easier but I still was having issues with adobe's transitions and various DVD burning programs glitching. So I already had the edit decks for the camcorder's tapes. It was just less heartbreak to edit on them. But it was interlaced again. So I knew a bit about psf from studying deinterlacing but had never really tried it. So I tried a few times to get the signal right and saw nothing but a mess. Until I finally properly connected the decks with ref signals. Then I successfully played back a 29.97psf image on a BSP tape and recorded it with a BM shuttle. Put it on the computer and there was a 29.97p image. Then I took the 60i footage and skipped the computer and put it straight on a standalone dvd recorder and played that back. Looked like progressive because I wasnt messing with the links in the chain. So I don't hate interlacing anymore. But I don't like motion stuttering which is my concern for the 3:2 footage. But I am ignorant to properly done 3:2 mixed with video. If I am careful it may not be an issue at all. I read that Perry had worked with a very similar Teranex unit to the one I'm using and I was hoping it might be a big part of the answer for film on video. But I really need to get this NPR finished so I can get on the next project and just see for myself and stop bugging you guys. I was just curious and "armchair filming" I suppose.


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#9 steve waschka

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Posted 29 June 2015 - 10:04 PM

Not that there isnt plenty of the footage out there already... But samples:

 

The bvw-d600ws processed to 29.97psf on the Teranex [horrifyingly humid shoot... the lenses are better than they come across here. And dont ask what I white balanced on. I should have color corrected before I let that one go. For whatever reason I did not]

 

The sdx-900 recorded on 30p setting and output thru onboard SDI straight to BM shuttle.


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#10 steve waschka

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Posted 07 July 2015 - 08:32 AM

And thankyou David. I look for your responses when reading others topics. I respect your opinions. And to everyone else helping me fumble through.
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