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Fixing Incorrect standards conversion

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Jack Bonnett
Fixing Incorrect standards conversion
on Jun 19, 2013 at 10:14:16 am

I've been asking quite a lot of standards conversion questions recently and I fear I know the answer to this one already but I'll ask it anyway.

We have been sent a load of files from a supplier to edit into shorter versions and reels. The files are very high quality .tp files with custom metadata. Already tricky. We have to rip these files with MPEG Streamclip, as it and VLC are the only two try to maintain 5.1 audio and then edit the files. Even more tricky.

The files are all at 29.97 and we're in PAL land which further complicates things with other suppliers. The question is some of this content has clearly been converted from 23.98 to 29.97 simply by adding a repeated frame every fifth progressive frame. Is there a way to remove this repeated frame without having to go through each of the clips, manually delete it, play the file back out without the frame, reconform to 23.98, and then try and then retime, resyc and potentially pitch shift the audio?

I'm guessing not.

Cheers again guys


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Rafael Amador
Re: Fixing Incorrect standards conversion
on Jun 19, 2013 at 10:40:03 am

That is call "Added pull-down", and there are ways to remove it automatically.
You have to do what is "Remove pull-down" or "Reverse Telecine" to get rid of the repeated fields.

I have no much experience on this because I'm in PAL-Land, but I know that there are different kind of pull-down and depending of the kind you are working with you will need to use ne application or another.
In this page, Apple explain about how to deal with certain kinds of PD in FC and CinemaTools:
http://documentation.apple.com/en/cinematools/usermanual/index.html#chapter...
Compressor can as well do "Reverse Telecine":
http://forums.creativecow.net/readpost/8/1080600

AE can also (I've tried) remove easily some PD patterns.
There is a lot of info in this forum (SEARCH: pull down removal) and in Google.
rafael


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Jack Bonnett
Re: Fixing Incorrect standards conversion
on Jun 19, 2013 at 11:33:50 am

Thanks Rafael,

I'm in PAL land too which is partly why this is proving such a headache all round. This footage that we have also has to be edited in with files that appear to be true 29.97 files with no pulldown added and I think, with me at least, this is what is going wrong. In the past I think that each of these clips has gone out as it's own discreet file and the display TVs have been left to sort of removing the pulldown etc.

Going forwards any advice from anybody on what the best way to work with this material is considering there's just me to do everything? At the moment I'm thinking conform everything to 23.98 and work with that but I'm not sure what this will do to audio sync etc.

I expect I'm going to get sent some PAL content too in the future just to further confuse things.

My ongoing thanks all.


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Rafael Amador
Re: Fixing Incorrect standards conversion
on Jun 19, 2013 at 11:59:33 am

[Jack Bonnett] " At the moment I'm thinking conform everything to 23.98 and work with that but I'm not sure what this will do to audio sync etc."
That makes no sense.
The only you will get is to making the stuff running slower (80%) and the pull down will still be there.
How you gonna edit that?
rafael


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Jack Bonnett
Re: Fixing Incorrect standards conversion
on Jun 19, 2013 at 12:30:08 pm

Fair enough...... So live with the pulldown in the content with and make sure that the clients know it's there?

They've complained about some of the footage being jerky before......is all

Could I remove the pulldown with repeated frames and then add interlaced field render pulldown back in for example as that would give a smoother result? As this is going out on TV screens.....

Or am I missing something?



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Jack Bonnett
Re: Fixing Incorrect standards conversion
on Jun 19, 2013 at 2:14:18 pm

Sorry I shouldn't have said 'conform' in the earlier post that was the wrong terminology and confused things.

At the moment in order to mix these files together I'm thinking I need to reverse telecine the 29.97 files with repeat frames to remove them and give me an original 23.98 file and then add the pulldown back in from AE or Compressor with blended fields so that I get smoother motion when played back on a screen and combined with the genuine 29.97 footage.

Does this sound like a logical workflow or have I overcomplicated the issue?

I'll cross the PAL bridge when I get to it.



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Mark Spano
Re: Fixing Incorrect standards conversion
on Jun 21, 2013 at 5:20:55 pm

Reverse telecine only works with proper 2:3 pulldown. It will not work at all for what you are trying to do, which is to remove every fifth frame. For that, you need to do it manually, as there is no automatic solution. In the past, I've invoked FCP and MadRuby. Drop the offending clip into a matching FCP timeline, and with MadRuby you can have it learn a keyboard sequence to step forward four frames, mark in, mark out, ripple delete. Then MadRuby can fire this learned macro off as many times as you want (to save you the carpal effects). When done, export same as source, and then load into Cinema Tools and conform to 23.98. Now you have the original 23.98 clip with the offending pulldown removed.



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