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Pulldown through the teranex 23.98-->29.97

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Dan Packman
Pulldown through the teranex 23.98-->29.97
on Jan 24, 2013 at 8:50:48 pm

Hi all,

I'm trying to lay a show from FCP 7 at 23.98 to an HDCAM (Sony 1800) through a teranex 2D to result in 29.97/59.97i HDCAM tape with the show that starts at 01:00:00:00.

I am setting up my sequence and tape to start at 01:00:00:00. When I lay off the tape, the first 7 or so frames are a still frame of the first frame in my sequence. After that, it plays fine.

I adjusted the sequence to start in black at 00:59:50:00 and have the show start 5 frames earlier at 00:59:59:19. I then started assembling on the tape at 00:59:50:00. This yielded a show that starts on the lower field of 01:00:00:00 as opposed to the upper field.

How would I need to set up FCP, teranex, and deck to have the show start on the top field of 01:00:00:00?

Thanks and let me know if you have any questions.

-Dan


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Chad Brewer
Re: Pulldown through the teranex 23.98-->29.97
on Jan 24, 2013 at 10:46:06 pm

What capture I/O card/device are you using with your Mac?

Is that card/device being fed video reference?
Is the HDW-D1800 being fed video reference or is it set for input video?

What's your device control in FCP set to? Is it still on a 23.98 setting like your sequence? If the device control isn't set to a 29.97/59.94i setting, this could account for the inaccurate edit.

Chad Brewer
Senior Videotape Operator
TeleVersions, LLC - Chicago


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Dan Packman
Re: Pulldown through the teranex 23.98-->29.97
on Jan 25, 2013 at 6:55:26 pm

I'll do my best to answer all these as best I can:

Blackmagic Decklink HD Extreme.
It is being fed HD 1080 59.94i reference.
The 1800 is being fed reference from the video.
FCP is set for 23.98 but device control is 1080 59.94i.

Does that answer all your questions or do you need more info?

THANKS!

-Dan


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Chad Brewer
Re: Pulldown through the teranex 23.98-->29.97
on Jan 25, 2013 at 7:38:26 pm

Dan,

I believe you're saying that your program is now starting on field 2 of TC 01:00:00:00 instead of field 1. I've seen this with this same card and same VTR.

It takes some trial and error with doing multiple edits to tape just past the program start time and then going back and checking before committing to the entire layoff, but change your device control setting's "playback offset" option between 0, +1, +2, +3, +4 each time and see if changing that moves the edit one field earlier. This has worked for me in the past when the edit was landing one field late.

Let me know if adjusting the playback offset fixes it for you.

Chad Brewer
Senior Videotape Operator
TeleVersions, LLC - Chicago


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Dan Packman
Re: Pulldown through the teranex 23.98-->29.97
on Jan 30, 2013 at 9:25:33 pm

Hi Chad,

I was finally able to test it and when I went to recreate the issue, It laid off fine. I ended up setting my sequence to start at 00:59:59:00 and have the head of my clip on 0059:59:19. The In point on the tape was 00:59:59:00 and my program started at 01:00:00:00. I believe the culprit in this scenario was the scene detection on the teranex. I had to set it to Film or Video but not Auto Any ideas on why this would work?

THANKS!


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Chad Brewer
Re: Pulldown through the teranex 23.98-->29.97
on Feb 1, 2013 at 7:00:09 pm

Hey Dan,

I'm glad you finally were able to get the tape laid off properly.
I'm only familiar with the Teranex models that were sold under Teranex before they were acquired by Blackmagic, so if your model is a Blackmagic model you might have some different options in your menus than the ones I see, but not sure:
I only have "film/video/auto" selections in the SOURCE option.
The scene detection option I have is simply an on or off setting - the default being set to on.

Changes to either of these settings may change the frame processing delay through the Teranex, thus you getting a different amount of delay that ended up being correct for the edit. These settings aren't meant to adjust timing though, they are to adjust certain aspects of the conversion processes - but which of course can affect timing. For instance scene detection brings the aperture buffer down from 4 fields to 2 fields for the first new converted frame after a cut, if I recall correctly.

I for one, believe the issue you were experiencing is related to sometimes transient polling issues with FCP's device control and various VTR's as I've seen layoffs being 1 frame early or late - RANDOMLY. I can lay off the same exact sequence through the same exact signal path sometimes 10 times in a row and it's dead on. Then I can do it another ten 10 times without changing ANYTHING and 4 out of 10 times it's a frame off. And I'm talking about without doing any signal processing! - no Teranex, no converter or conversion of any kind.

It used to drive me insane as I do tape lay-offs every single day. I'd been over the issue with Blackmagic and AJA at length, and finally gave up and learned that sometimes you have to retry or change device control playback offsets or what have you to compensate for the transient weirdness. At least this has been my experience.

Chad Brewer
Senior Videotape Operator
TeleVersions, LLC - Chicago


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