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30p converted to 24p


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#1 Daniel Carruthers

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Posted 05 December 2006 - 06:40 PM

hey im shooting a feature with the dvx100a and i accidentally shot a entire scene in 30p mode!!!
i did some slow motion shots before that scene shooting in 30p to convert to 48frames and i forgot to switch the camera back to 24p advanvced.
so my question is can the 30p footage be convereted back into 24p in post production, we are hoping to get a theatrical release and dvd release, will this cause any problems, will we just be better of re-shooting that scene?
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#2 Eugene Lehnert

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Posted 05 December 2006 - 08:47 PM

If it's not too expensive I would reshoot the scene. Otherwise you can convert the footage to 24p but the footage will suffer and it will be either time consuming or expensive.

You can actually use Compressor to convert the footage from 30p to 23.98. The amount of motion there is in the video will determine how well the video looks when you convert it. If there isn't a lot of motion it might be passable.

There are more expensive services like using a SNELL UKON converter but that will be pricey and in my opinion compressor can do just as good a job. The UKON will do it in real-time though. Where as Compressor could take days depending on your computer.

http://www.dvfilm.com/ Has a product called DVFilm Maker wich is about $100 I think. It's fairly fast and does a pretty good job. Just don't use it on a cut piece. Only use it on raw uncut footage. It doesn't handle cuts very well as it just mixes frames together.

I hope this helps.
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#3 Daniel Carruthers

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Posted 05 December 2006 - 10:34 PM

If it's not too expensive I would reshoot the scene. Otherwise you can convert the footage to 24p but the footage will suffer and it will be either time consuming or expensive.

You can actually use Compressor to convert the footage from 30p to 23.98. The amount of motion there is in the video will determine how well the video looks when you convert it. If there isn't a lot of motion it might be passable.

There are more expensive services like using a SNELL UKON converter but that will be pricey and in my opinion compressor can do just as good a job. The UKON will do it in real-time though. Where as Compressor could take days depending on your computer.

http://www.dvfilm.com/ Has a product called DVFilm Maker wich is about $100 I think. It's fairly fast and does a pretty good job. Just don't use it on a cut piece. Only use it on raw uncut footage. It doesn't handle cuts very well as it just mixes frames together.

I hope this helps.


thanks for the help.
but lets say we just left that scene as 30p would it cause problems distributing it on dvd or possibly film??
i know you can convert 30p to 48frames by slowing the footage down to 80% and playing it back in a 24p timeline, could you just speed up the footage by a couple percent and play it back on a 24p timeline,would that work?
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#4 Allen Achterberg

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Posted 05 December 2006 - 11:43 PM

There is a great program out there for After Effects called Twixtor. Use this in conjunction with Reelsmart's De Interlacer to get 60P. From there you can convert it to 24P no problem, I have done with with amazing results (when I had an XL1S)

Although the Plug does require getting to know it, there are no presets and every scene will render differently with the same settings, so tweaking is crucual to get the smoothest results.

If you need Further Help, messege me.

All The Best,
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#5 Thomas Worth

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Posted 05 December 2006 - 11:59 PM

Use this in conjunction with Reelsmart's De Interlacer to get 60P.

He can't do this because the footage was shot 30p -- there's nothing to deinterlace. If he had shot 60i, it would have been easier to fix the problem.

If you get a DVD release, you may be able to avoid the 30p --> 24p conversion. Your 24pA material can be converted (back) to 29.97 using the 3:2 pulldown method instead of the 2:3:3:2, which will look smoother. And then your 30p scenes will drop in as-is, since they are already 29.97. The resulting MPEG2 stream for DVD would be encoded as 29.97 (60i) instead of 23.976p. This is not a great solution (your entire movie will be interlaced), but a solution nonetheless.

Although it is possible to convert 30p to 24p, it is the worst possible perdicament for 24p conversion. Any other frame rate would have provided a better result. The best thing to do would be to use Twixtor (without FieldsKit). Twixtor will try to do some motion compensation to the image, but it's not going to be perfect. There may be a "gloopy" look to the footage after conversion.
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#6 Allen Achterberg

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Posted 06 December 2006 - 02:33 AM

----Yes he can, I've done it, turns out smooth. A Progressive source can be seen as interlaced, no problem (at least I never ran into one) Even if it WOULD create a problem, he can use Twixtor's Re-Interlacer to do this, and do as I suggested. (although I never needed to do such)


"Drop the scene in as-is"

THE PROBLEM with that is, is that the motion won't match 24P, and 30P have distinctive looks. A difference will be seen. If you want all of your motion to match, including fade ins/outs it should be editied in the same timeline with the same frame rate. This option is not a good idea for the other reason, He thinks a film out is possible. It will need to be 24P in the end regardless.


Will look better than 30P regardless.

Use the fieldskit, it will look choppy if you don't. Create an interlaced file from it, then do the conversion. I've noticed the Fieldskit will give you best results, even if from an progressive source.

it should go 29.97--->60P---->23.98. that's your 24P, without too much quality loss. Just do as much testing as possible if you decide to go this route.

All the Best

Edited by Allen Achterberg, 06 December 2006 - 02:35 AM.

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#7 Thomas Worth

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Posted 06 December 2006 - 03:27 AM

Yes he can, I've done it, turns out smooth. A Progressive source can be seen as interlaced, no problem

A progressive source being seen as interlaced would result in double frames. The only point in deinterlacing footage is to extract full-frame spatial data from the video stream (in the case pf 60i, that would be 60p). You already have this full-frame spatial data with a progressive stream (30p). I don't see how "doubling up" frames would give you any advantage. You can simply set Twixtor's input to 29.97, and its output to 23.976, instead of what you suggest, which would be 59.94 and 23.976.

THE PROBLEM with that is, is that the motion won't match 24P, and 30P have distinctive looks.

The motion isn't going to match anyway! The footage was shot at 30p. It doesn't matter what you do, it's never going to look the same as footage originally shot at 24p. At least with the "as is" method, the footage will be free of post artifacts.

The issue really comes down to what's acceptable to Daniel. Personally, I agree with you, I'd probably deal with a mediocre looking 30p-converted-to-24p scene for the sake of preserving the 24p timeline. But this might not be acceptable to everyone. I'm just offering an alternative.
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#8 Allen Achterberg

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Posted 06 December 2006 - 03:46 AM

conversion to 24P It will be a closer match, I think I'll do a test, and post it online. I own a HVX200, I'll shoot 30P have it converted and compare it to 24PN footage.

Will be up shortly.

All the Best.
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#9 Thomas Worth

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Posted 06 December 2006 - 04:50 AM

conversion to 24P It will be a closer match, I think I'll do a test, and post it online. I own a HVX200, I'll shoot 30P have it converted and compare it to 24PN footage.

That would be great. Don't be afraid to encode your web movie at a large frame size with a high bitrate. The higher quality, the better.
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#10 Allen Achterberg

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Posted 06 December 2006 - 05:35 AM

Have any suggestions as to where I can host it? The only place I've really uploaded video is on youtube, and it's awful.

Thanks,
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#11 Allen Achterberg

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Posted 06 December 2006 - 06:10 AM

the test will have to wait, I'll try to have it up tomorrow evening.

All the Best
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#12 Daniel Carruthers

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Posted 06 December 2006 - 08:10 AM

the test will have to wait, I'll try to have it up tomorrow evening.

All the Best

thanks for your suggestions i would really like to see your tests.
since its only 1 scene out of entire feature i would really like to convert the 30p to 24, instead of interlacing the whole movie.
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#13 Daniel Carruthers

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Posted 11 December 2006 - 10:03 AM

hi allen,
where you able to do the test yet?
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#14 chloemarqz

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Posted 27 November 2009 - 03:36 AM

The Plug does require getting to know it, there are no presets and every scene will render differently with the same settings, so tweaking is crucual to get the smoothest results.




yours,
chloe

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#15 John Sprung

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Posted 27 November 2009 - 05:26 AM

we are hoping to get a theatrical release and dvd release,


For a theatrical quality fix, Twixtor won't be good enough. Take it to a post facility such as FotoKem that has the new Arri Relativity software. Relativity does real motion vectors, not just blur-betweens.

Cut the scene in 30p, then add 15 frame handles on both ends of every shot. Put it thru Relativity with the long handles, tell the operator about the handles so they won't try to tweak the cuts. Then take the 24p that comes from Relativity and trim off the handles. Handles give Relativity motion information it can use to get the vectors right before and after the places you really want your cuts.



-- J.S.
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