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  #11  
Old 08-31-2011, 09:25 AM
SZE SZE is offline
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Default Re: 24p - 23.976 fps video & 24 fps audio

I think the NTSC-compatibility thing is the the main reason they want to keep it at 23.976 for now (NTSC screenings, etc).

Quote:
As the final process Iīd pull up the master to 24P and deliver 24.00@48k
pretty easy.
Frank, sorry if this seems like a very basic question, but how do you actually do your pull up to 24 at the deliverables stage? And when you say you do all the work at 23.98 (no pull-up) do you mean you work at 23.976?

Thanks

Last edited by SZE; 08-31-2011 at 09:30 AM. Reason: Additional request for info
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  #12  
Old 08-31-2011, 09:30 AM
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minister minister is offline
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Default Re: 24p - 23.976 fps video & 24 fps audio

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Originally Posted by SZE View Post
I think the NTSC-compatibility thing is the the main reason they want to keep it at 23.976 for now (NTSC screenings, etc).
Tape. HD Cam and HD Cam SR are 23.976. TV, Festivals, Distribution Deliverables......
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  #13  
Old 08-31-2011, 11:09 AM
Frank Kruse Frank Kruse is offline
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Default Re: 24p - 23.976 fps video & 24 fps audio

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Originally Posted by minister View Post
Tape. HD Cam and HD Cam SR are 23.976. TV, Festivals, Distribution Deliverables......
Yes but they HD can easily run at 24 PsF.
Just wondering why force the whole chain to pull-down when only one segment (TV, DVD) needs NTSC picture. Wouldnīt it be easy to do a 24 to 29,97 transfer only for those future niche media?

24 to 29.97 has been done for decades why force the HD cameras to 23.98 now. Just wondering.
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  #14  
Old 08-31-2011, 11:11 AM
Frank Kruse Frank Kruse is offline
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Default Re: 24p - 23.976 fps video & 24 fps audio

Quote:
Originally Posted by SZE View Post
I think the NTSC-compatibility thing is the the main reason they want to keep it at 23.976 for now (NTSC screenings, etc).



Frank, sorry if this seems like a very basic question, but how do you actually do your pull up to 24 at the deliverables stage? And when you say you do all the work at 23.98 (no pull-up) do you mean you work at 23.976?

Thanks
You simply re-import your master to a new session with SRC and pull-up enabled. The result is a 48k master running at 24.00
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  #15  
Old 08-31-2011, 12:22 PM
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Default Re: 24p - 23.976 fps video & 24 fps audio

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Originally Posted by Frank Kruse View Post
Yes but they HD can easily run at 24 PsF.
Just wondering why force the whole chain to pull-down when only one segment (TV, DVD) needs NTSC picture. Wouldnīt it be easy to do a 24 to 29,97 transfer only for those future niche media?

24 to 29.97 has been done for decades why force the HD cameras to 23.98 now. Just wondering.
Every TV show and Amerikkan film I work on has an HD version and a NTSC SD version. 23.976 and 29.97 means they are the exact same running time. For the time being, in many instances, they broadcast both.

The European films I have worked on have had 24, 25, and 23.976 versions.
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  #16  
Old 08-31-2011, 01:00 PM
tom_lowe tom_lowe is offline
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Default Re: 24p - 23.976 fps video & 24 fps audio

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Originally Posted by Frank Kruse View Post

24 to 29.97 has been done for decades why force the HD cameras to 23.98 now. Just wondering.
Yes it has, but 24 doesn't go into 29.97, but by 2:3 pull-down, it would go into 30. Ergo, to get 24 in to 29.97 you have to drop the film speed by 0.1% to 23.976 so that you can get 29.97. Shooting 23.976 avoids this.

If cameras shot at 24 dead and then played out on an NTSC system, they would have to drop the speed by 0.1% or do frame rate conversion by means other than 2:3.
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  #17  
Old 09-01-2011, 12:18 AM
Frank Kruse Frank Kruse is offline
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Default Re: 24p - 23.976 fps video & 24 fps audio

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Originally Posted by tom_lowe View Post
Yes it has, but 24 doesn't go into 29.97, but by 2:3 pull-down, it would go into 30. Ergo, to get 24 in to 29.97 you have to drop the film speed by 0.1% to 23.976 so that you can get 29.97. Shooting 23.976 avoids this.

If cameras shot at 24 dead and then played out on an NTSC system, they would have to drop the speed by 0.1% or do frame rate conversion by means other than 2:3.
I know, but hasnīt this been done for decades with 24fps film? The only difference is that the HD camera shoots at pull-down rate directly instead of doing the pulldown during telecine?

What I meant was why not do the entire post at 24.00 and ONLY pull down the image for NTSC media (TV, DVD).

Since BD, DCP, prints etc. all support true 24.00 why force the entire post-chain incl. camera-speed to 23.98 if only a small part (and even smaller in the future) of the release media can only play 29.97?

Why "terrorise" everyone with pull-down confusion for a future niche product. Why not do the pull down at the end only for the media that needs pull-down?

(Speaking strickly of theatrical film here)
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  #18  
Old 09-01-2011, 07:01 AM
tom_lowe tom_lowe is offline
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Default Re: 24p - 23.976 fps video & 24 fps audio

I guess it's down to simplifying it. Say you shot at 24 and then had to display on a screen only capable of 60i, as is the case with lots of older and low-end displays. The camera would either have to pull-down, or you'd have to put it in to an edit suite, pull-down and then export.

23.98 means it's close enough to 24P to pull-up if required, but for TV where it has to be compatible with old NTSC standards, 23.98 means you can deliver for HD and SD without having to do any conversions, and if everything is 23.98, it avoids confusion over what has been pulled-down and what has to be pulled-down.

It would be nice if there was a clean start with HD running at 24 or 48, but then maintaining compatibility with SD systems unfortunately stops that. They could have done it with DVB and ATSC too, but that had to maintain compatibility with analogue sets.
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  #19  
Old 09-03-2011, 09:43 AM
SZE SZE is offline
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Default Re: 24p - 23.976 fps video & 24 fps audio

Thanks for all the replies.

We are starting with a trailer of the film, so a few days ago I received a QuickTime MJPEG 720p @ 23.976 fps. This was imported into a Pro Tools session also set to 23.976 fps, and when the OMF was imported into Pro Tools, everything sync up, so I presume the OMF is also 23.976?

Now I have some more doubts and am still a bit confused about what is actually happening here.

When I record my master in Pro Tools ready to pass on pic. editorial, the new audio files created show up in the Workspace as 48kHz files. Doesn't 48kHz equate to 24 fps, and shouldn't my new files be 47,952 files as my session is running at 23.976 fps?

My principal concern is how my master audio is going to sync up / playback in FCP, as the film is being kept at 23.976 fps right up until deliverables / printmaster.

What do I need to do to output a file for them that will sync up and will not be pulled up/down or messed about with in any way by FCP?

Thanks
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  #20  
Old 09-03-2011, 09:46 AM
Frank Kruse Frank Kruse is offline
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Default Re: 24p - 23.976 fps video & 24 fps audio

Quote:
Originally Posted by SZE View Post
Thanks for all the replies.

We are starting with a trailer of the film, so a few days ago I received a QuickTime MJPEG 720p @ 23.976 fps. This was imported into a Pro Tools session also set to 23.976 fps, and when the OMF was imported into Pro Tools, everything sync up, so I presume the OMF is also 23.976?

Now I have some more doubts and am still a bit confused about what is actually happening here.

When I record my master in Pro Tools ready to pass on pic. editorial, the new audio files created show up in the Workspace as 48kHz files. Doesn't 48kHz equate to 24 fps, and shouldn't my new files be 47,952 files as my session is running at 23.976 fps?

My principal concern is how my master audio is going to sync up / playback in FCP, as the film is being kept at 23.976 fps right up until deliverables / printmaster.

What do I need to do to output a file for them that will sync up and will not be pulled up/down or messed about with in any way by FCP?

Thanks
48k doesnīt equate to 24fps. It equates to what ever the original camera shooting speed was, assuming sound was recorded at 48k. Itīs all relative. If your film was shot at 4 fps and release format is 4fps then 4fps is 100% speed running in sync to 48k audio. a digtal audio recorder captures at a given sample rate and wether it will run in sync or not depends on the playback clock i.e. sample-frequency.

Again: In PT the TC ruler is only a counter. Nothing else. Unless you set the session setup to pull up/down it will run at 48k no matter what TC you chose.

Like I said before: in the digital world sound speed it set by sample frequency not TC.


If your film was shot at 23.98 and post is done at that speed and release format is also 23.98 you donīt need to pull anything up or down.

You could even set your session to 25fps and everything will still play back in sync. only the TC in picture will not match PTīs TC ruler.
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