FORUMS: list search recent posts

DVCAM offline 29.97 / online to HDCAM 23.98

COW Forums : Avid Media Composer

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
JD Marlow
DVCAM offline 29.97 / online to HDCAM 23.98
on Jan 2, 2013 at 3:22:48 am

Hi everybody,

I'm a recent convert from Final Cut to Media Composer and have a common workflow question.  I've got a project that was primarily film originated - transferred to HDCAM at 23.98 fps.  Downconverted DVCAM tapes were made at 29.97 NDF, and these were digitized improperly at 29.97.  They have already been used to cut with, and so we now have the obvious problem of having to online these back to the HDCAMs.

I know on the timeline level you can remove pulldown using a Motion effect and precompute that into your sequence.  But I haven't figured out a way to effectively create new clips for each tape that was captured, so that we effectively have the equivalent of digitized 23.98 tapes.  In the Final Cut world I would run a reverse telecine in Compressor or Cinema Tools, but just don't have enough Avid experience to solve this problem.

If anyone has suggestions I would be glad to hear them!

Thanks in advance,

JD

JD Marlow
jd@jdmarlow.com
http://www.jdmarlow.com


Return to posts index

Richard Sanchez
Re: DVCAM offline 29.97 / online to HDCAM 23.98
on Jan 2, 2013 at 5:26:40 am

You offlined from 29.97 downconverts of 23.976 masters? You mentioned that this was mostly film transferred material, do your 29.97 downconverts include edgecode or any information that would correspond to your 23.976 masters? If not, you're going to have to overcut. Not fun, not fast. Sorry.

Richard Sanchez
Los Angeles, CA

"We are the facilitators of our own creative evolution." - Bill Hicks


Return to posts index

Michael Phillips
Re: DVCAM offline 29.97 / online to HDCAM 23.98
on Jan 2, 2013 at 1:41:54 pm

Aside from the metadata issues that Richard mentions, you can always open your 29.97 bins in a 23.976 project. If you edit directly from the clips, they will have a motion adapter automatically applied which is in essence a pulldown removal in this scenario. If you transcode the master clips in the bin, they will become native 23.975 and have a 24fps timecode- this assumes that someone else is keeping the database for KeyKode and such for any film needs as that is usually tracked on the clip as well in context of editorial.

Michael


Return to posts index


JD Marlow
Re: DVCAM offline 29.97 / online to HDCAM 23.98
on Jan 2, 2013 at 2:01:23 pm

Hi guys,

Thanks for your thoughtful responses. I don't know yet if there are proper picture burn ins for either TC or KeyKode for these downconverts. The program is for broadcast and will likely not be going back to the film, though. The 29.97 clips have already been cut with in a 23.976 project so the motion adapters are probably already on there.

But I've done a few tests where I consolidate a sequence with 29.97 clips inside a 23.976 project and the condoliated clips are still 29.97 - AVID doesn't create new subclips with the motion adapter "baked in".

So the alternative is, as you mentioned, transcoding the original clips to 23.976 and cut the new clips back into the sequnce (I wouldn't be able to re-link the clips in the existing sequence to this new media, would I?). I'm wondering: If I go to the trouble of doing this, will I eventually be able to batch capture from the HDCAM originals using the 23.98 timecode on the transcoded clips? If that were to work I'm assuming there would be some +1/-1 frame adjustments that would be needed. It's a shame when you transcode 29.97 to 23.98 at the bin level you have no control over properly removing pulldown cadence. I am considering just re-digitizing all the tapes properly and cutting them in again, depending on how many there are. I've also looked into some EDL conversion workflows which might be a more clever way of dealing with this (http://www.24p.com/30_24.htm).

Thanks again,

-JD

JD Marlow
jd@jdmarlow.com
http://www.jdmarlow.com


Return to posts index

Michael Phillips
Re: DVCAM offline 29.97 / online to HDCAM 23.98
on Jan 2, 2013 at 3:24:05 pm

You can transcode the sequence as well to get the 2"3 removal baked in to the sources. From there, an EDL or timeline will be fine for a recapture from the original HDCAM. Creating an EDL will be matchback as well, with a +/- 1 frame adjustment. If you do the transcode, then that is the frame, so farther adjustments needed if what you see is what you want.

This assumes that the 2:3 removal is correct. In most cases, and assuming a proper downconvert form the HDCAM to the SD tapes, that it was done NDF and "A" frames fall on timecodes ending on :x0 and :x5. If there is no burn-in on the original sources, then it will be difficult to see what the timecode relationship is/was in the process.

This needs to be done in a 100p/23.976 as SD will always count as NTSC as 24fps is a manufactured count, and SMPTE does not define 24fps timecode in SD sources (NTSC or PAL). Avid does this as a metadata template on the media to track both 30 and original 24fps timecode and the proper cadence for each clip.

And by the way... I am the MichaelP of 24p.com... :)

Michael


Return to posts index

JD Marlow
Re: DVCAM offline 29.97 / online to HDCAM 23.98
on Jan 2, 2013 at 6:38:12 pm

Michael,

Thanks for this info. I'll try out transcoding the sequence. I don't really want to re-capture or transcode all of the original material if I don't have to.

We are working in an HD project (1080p, 23.976). The only stuff that's SD are these downconversions from original film transfers. So if you're saying that, once we lock picture, I can transcode the entire sequence to some DNX codec (baking in motion adapters removing 2:3 on the SD clips) and then batch in the new clips that came from HDCAM tape then that sounds good to me. What I'm hoping is that once I transcode the sequence and decompose, there will be some *.new clips for the previously 29.97 clips, but now at 23.98 that I can use to batch with.

I had no idea the web site was yours - it's been a great resource for me!

Best,
JD

JD Marlow
jd@jdmarlow.com
http://www.jdmarlow.com


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]