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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

24P or 23.976P? That is the question.

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Frank Cueto

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I have a film-maker who is hell bent on shooting at 24fps his next project. His reasoning is that since he is aiming strictly for festivals, there is less chance of something going wrong since festivals request prints (24fps) or DCPs (also at 24fps).


I understand his concerns, but I really think that 23.976 will provide for a cleaner workflow when it comes time to generate all the other deliverables. Not only that, I know most digital productions run at 23.976 and most of the pipeline/workflows are expected to go along those lines and I would HATE for someone halfway thru the post to inadvertently produce something at 23.976 therefore throwing a monkey wrench.

Are there any guidelines regarding this or very heavy reasons to pick one or the other or are they freely exchangeable?

thanks

P.S. This is a repost from the ask mike most anything thread.
 
Most digital movies shoot at 23.976, not 24... I think Sony was even thinking of dropping the 24 option because too many people have tripped themselves up in post with it.

It's really not a picture issue. You can show 23.976 at 24 fps and vice-versa, it looks the same, there is no conversion needed. It's a sync issue for editing and mixing audio. Once you create a final master with audio at 23.976, I don't think there is any conversion necessary to show it at 24 fps, but I'm not sure. But I've shot about ten features at 23.976 and the only one where we had problems was the first digital feature I shot, where I used 24, not 23.976. The editor said that the audio during the mix kept slipping in sync. So I've never used 24 since then.
 
24.000 is mainly used in Europe and PAL based countries when not shooting 25.000. 23.976 has become the "new" frame rate standard whenever broadcast, television and such are the primary deliverable. If delivering to both 23.976 or 24.000 one of then will need a sample rate conversion somewhere in the process - either on the final audio stems etc.

Michael
 
In the interest of avoiding wrong info on this thread.

To my knowledge, 29.976 is a WRONG rate. The proper one is 29.97.
 
When it comes to the Project settings of 24fps vs 23.976fps

No matter what if you are putting this footage into digital editing and going to television it is going to end up turning 23.976 at some point so begin as 23.976.

Your film maker shooting for Festivals, DCP, is great fine not a problem.
There is no penalty at all for shooting in 23.976. No matter if its DCP's, DSMs, Tape outpout, Web output, DCDMs, DVD and even FILMs.

Stick to 23.976

THE only 1 time that we have been able to come up with that you would even consider going 24 solid.
Is in STOP MOTION Animation, please do not make it hard on you in post with potential problems. I just shot a feature where they switched to 24 1/2 way threw the project and this cost issues and problems that took lots of time and headache to deal with in post.
Make sure to have your camera and Audio BOTH set up for 23.976 and you shall have happy trails.



Best of luck
Luis
 
In a film workflow 24 is fine as long as all departments know to sync sound at 24.00 as well

23.98 is a North American standard and places nicer with NTSC. I shoot 24.00 in Europe (easy to go to 25) and no problems with DCPs, but if I am shooting for North America I shoot 23.98.

as Julio says film runs at 24 without any problems.

David
 
Johnny Friday said:
Michael,
you mention TV....but aren't all/most tv delieverables 29.976 ?
Click to expand...

Yes, deliverables can be anything from 29.97 with pulldown, 25fps with 4.1% speed up etc. I like to think of a production master and everything else as a deliverable from that. If delivering to both theatrical and US broadcast for example, there will be a sample rate conversion on one of them as 48kHz will need to be in sync with both picture rates. The same for a 23.976 to 25 with 4.1 speed up (frame for frame).

Michael
 
By the way, I wrote up a quick universal mastering workflow guide for 23.976p, 24p and 25p at http://24p.com/wordpress/
Although written for Media Composer, process and math would work for any system.

Michael
 
I just worked on a film where we made the decision to shoot 24 straight rather than 23.976.

At the time we didn't know who some of our post vendors were going to be; if we went to established post houses or used freelancers and so on. The need to exchange EDLs between multiple vendors is always a source of confusion and solving one issue by going "Well, most programs see an edl and default to 24fps straight unless the user intervenes, it's a safer bet than cleaning up edits during final conform"

The conversion in either direction is easy and minimal.
 
Tell him that you will shoot it in 24fps because its trusted by the film industry. You can shoot 24fps but in post you will edit in 23.95 and it will be fine, how do I know?? I shot two feature films 24fps on a digital camera and Vegas pro ask for 24fps in film or 23.95. I went with 23.95 in post ,the video and sound sync no problem. This guy is old school so don't waist your time just tell him what he wants to hear, if he was educated he would know the new standards and what works.
 
Tony Harris said:
Tell him that you will shoot it in 24fps because its trusted by the film industry. You can shoot 24fps but in post you will edit in 23.95 and it will be fine, how do I know?? I shot two feature films 24fps on a digital camera and Vegas pro ask for 24fps in film or 23.95. I went with 23.95 in post ,the video and sound sync no problem. This guy is old school so don't waist your time just tell him what he wants to hear, if he was educated he would know the new standards and what works.
Click to expand...

In this scenario the audio was either recorded at 48.048kHz and played back sample for sample at 48kHz. Anything else will be a sample rate conversion in a project/timeline that is 23.976@48kHz.

Michael
 
This brings up an interesting issue.

THE ONLY REASON 23.98 (23.976) is in play, is that it "was" easily converted to 29.97 (a legacy format for analog transmission, and CRT TVs - were are moving away from this - most already have).

The time base set at 23.98 corrupts exposure of faster frame rates under cycled light. Example: 23.98 Time base - shooting at 48fps. True fame rate is 47.96. This may not sound like a big issue, but you will never find HMI safe speeds in a 23.98 Time base. Can't be done. The math isn't exact - like it needs to be - has to be, especially when using a rolling shutter. You get flicker or other visual anomalies. So bad, for the occasional high speed shot, I'll change the timebase to 24 and let the post guys deal with it.

I was happy to see that RED recently changed the display frame rates in the varispeed menu to their accurate speeds (I.E. 47.96 as mentioned above). 30, 40, 60, 120 (safe speeds) are not available in the menu when using a 23.98 Time Base. Many will write back and say "adjust your shutter". Not possible. Safe speeds are safe at any angle.

What that really means is that your normal frame rate -23.98 isnt HMI safe either. you may not notice it for brief shots, but try scubbing through a lengthly locked off shot at 23.98 lit under hmi, or any discharge lamps, and you will see the variance. Funny how .02 of a second makes such a difference, and even more the further you get from 23.98.

Unfortunately many accessories cant deal with 24fps - for instance I cant get IDX Wevi's to transmit 24fps, and some monitors choke and end up delaying images for a few frames when displaying 24fps.

Shoot at 24, post in 23.98 if that makes everyone happy.

For production - I vote to kick 23.98 off the island.
 
You are right I did change to audio to 16 48004HZ to sync with the video
 
bjonsson said:
This brings up an interesting issue.

THE ONLY REASON 23.98 (23.976) is in play, is that it "was" easily converted to 29.97 (a legacy format for analog transmission, and CRT TVs - were are moving away from this - most already have).

The time base set at 23.98 corrupts exposure of faster frame rates under cycled light. Example: 23.98 Time base - shooting at 48fps. True fame rate is 47.96. This may not sound like a big issue, but you will never find HMI safe speeds in a 23.98 Time base. Can't be done. The math isn't exact - like it needs to be - has to be, especially when using a rolling shutter. You get flicker or other visual anomalies. So bad, for the occasional high speed shot, I'll change the timebase to 24 and let the post guys deal with it.

I was happy to see that RED recently changed the display frame rates in the varispeed menu to their accurate speeds (I.E. 47.96 as mentioned above). 30, 40, 60, 120 (safe speeds) are not available in the menu when using a 23.98 Time Base. Many will write back and say "adjust your shutter". Not possible. Safe speeds are safe at any angle.

What that really means is that your normal frame rate -23.98 isnt HMI safe either. you may not notice it for brief shots, but try scubbing through a lengthly locked off shot at 23.98 lit under hmi, or any discharge lamps, and you will see the variance. Funny how .02 of a second makes such a difference, and even more the further you get from 23.98.

Unfortunately many accessories cant deal with 24fps - for instance I cant get IDX Wevi's to transmit 24fps, and some monitors choke and end up delaying images for a few frames when displaying 24fps.

Shoot at 24, post in 23.98 if that makes everyone happy.

For production - I vote to kick 23.98 off the island.
Click to expand...

I believe what you are saying holds true for HMI's with magnetic ballasts not electronic ones. And with magnetic ballasts, I believe the only way 24.000 FPS becomes safe is if you use a 144 degree shutter, b/c this gives you a 1/60th shutter speed.
 
I always use 25fps for anything I do (I don't shoot features..but if I did I would).. 25fps converts to everything (ie, play back at 24 and adjust audio pitch, then convert that to 30fps if necessary..).. international release sorted ;) ..and is European tv friendly..which is what I most care about if im honest..
 
In my experience, audio is not recorded at a specific fps (especially when recorded externally). I have converted various short film projects to DCP, as a feature length compilation for the Digi60 Spring 2013 filmmaker's festival in Ottawa Canada this year. Audio has to be sped up 100.1% if the project originates as a 23.976fps video to keep sync with a 24fps DCP. There are settings within OpenDCP to handle this and I'm sure commercial tools provide that facility as well.

I created a guide which includes lessons learned and photos from actual exhibition using various DCP servers and projectors. Take a look and let me know if you've found anything different in your experience.

Cheers,
Jith.


http://dcp.treepotmedia.com
 
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