Reverse telecine option is greyed out?

Question

Level 2

233 points

Reverse telecine option is greyed out?

I have 29.97 fps interlaced material that I'm pretty sure has been telecined from 24 fps. The giveaway is that in FCP, when viewing the material at anything other than 100% size, it looks like every 4 frame is duplicated, but at 100% you don't see that effect.

However when I load it into Compressor (4.2.2) to try to reverse-telecine it into 24fps, the "reverse telecine" option is always greyed out no matter what I do or what transcoding setting I am using (e.g. Pro Res). I followed the Compressor user guide to the letter - applying a setting to the material, going to the video inspector, setting the frame rate as 29.97 - but under "retiming quality" reverse telecine is always greyed out and can't be selected.

Help!

Mac Pro, OS X El Capitan (10.11.2), 3.2 GHz Quad-Core Intel Xeon

Posted on Sep 10, 2016 3:59 AM

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Answer 1

BenB

Level 6

13,324 points

Sep 11, 2016 3:55 PM in response to Brendan Jones

That means there is no telecine metadata in the file. What is the origin of the file?

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Answer 2

Brendan Jones Author

Level 2

233 points

Sep 14, 2016 5:51 AM in response to BenB

The file is an interlaced MPEG 2 file. I was not aware that an MPEG 2 file could store telecine metadata. Is there any way to "force" reverse telecine?

Working out the cadence is trivial if the source is genuinely telecined, and if not the result will be rubbish anyway and the user will then know the source isn't telecined. So the metadata isn't really required, why grey the option out?

I would assume people using Compressor actually know what they are doing and don't need this kind of UI "protection".

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Answer 3

BenB

Level 6

13,324 points

Sep 15, 2016 6:31 PM in response to Brendan Jones

Once a file is MPEG-2, you're in a delivery codec, not a post-production codec. MPEG-2 doesn't telecine.

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Answer 4

Brendan Jones Author

Level 2

233 points

Sep 16, 2016 6:14 AM in response to BenB

Well you may be right from a specification perspective, but that doesn't change the fact that this particular 29.97 fps MPEG could, in fact, be reverse telecined. It doesn't take long to view the fields in the file to clearly see the cadence AA BB BC CD DD.

So it would be entirely possible to analyse the fields, detect the cadence, pull out the fields A B C D, and play them back at 24 fps progressive (or 23.98), and whaddya know - MPEG file successfully reverse telecined.

It's pretty ridiculous that basically I am forced to write my own software to do this when a commercial package has that capability built in but won't let you apply it.

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