25FPS to 24FPS

I have avoided this until now but I have a client who needs to create a 24P for festival circuit. Anybody with tips and techniques to offer will be rewarded with that nice fuzzy warm feeling you get from knowing you have helped a colleague in need!

I'd just slow it down. Nobody will notice the difference if they don't have absolute hearing of pitch.

Any other method will introduce artifacts.

I'd render the whole thing out at 25fps, then pull that file into a 24fps session and render that version out at 24fps using Change Attributes. It will be 4% slower, so the question is whether you want to use pitch correction to get the music and/or dialogue back to normal.

thanks for the response.

They are going to do a pitch change for it when they do the 5.1. I had thought of doing it through AE and Twixtor but its long and the possibility that twixtor will add something unexpected. I think I will propose what you said and just "re-brand" it to 24FPS and let the audio guy fix the pitch.

I'd render the whole thing out at 25fps, then pull that file into a 24fps session and render that version out at 24fps using Change Attributes. It will be 4% slower, so the question is whether you want to use pitch correction to get the music and/or dialogue back to normal.

ooo! Pitch correction? Is that in there too? Will it work on 5.1? Do you use easyDCP? Should I bight the bullet and get it?
....with all these questions it might seem like I spend way too long in a dark room on my own!

Which OS, Roen ?
On mac, try the good old Cinema Tools

Which OS, Roen ?
On mac, try the good old Cinema Tools

CT doesn't work on QT files from Resolve for some reason. Best best is to do as Mark says and bring it into a 24fps project and go from there.

Pitch correction for 5.1 is not trivial. You need to use good tool which keeps all channels in phase.
This is decent tool: https://www.zynaptiq.com/timefactoryii/
You can easily screw it- don't use apps which are not designed for 5.1 or clearly state how they process 5.1 files.

isn't fairlight capable to re-pitch an audio file?

walter that would be a good test if it does!

isn't fairlight capable to re-pitch an audio file?

This is the problem. You even don't know if it can. Another story is to know exactly how it does it
I would not test it with 5.1. Stereo is good for the beginning
In order to know if 5.1 is fine you need proper listening setup ( or you need to know that software is made and trusted to do 5.1 re-pitching).

isn't fairlight capable to re-pitch an audio file?

This is the problem. You even don't know if it can. Another story is to know exactly how it does it
I would not test it with 5.1. Stereo is good for the beginning
In order to know if 5.1 is fine you need proper listening setup ( or you need to know that software is made and trusted to do 5.1 re-pitching).

I don't do audio, that is why i asked.
My assumption is that a professional mixing package should do it, and with professional quality... (like protools does)

I assumed it would be a plug in in Fairlight and couldn't find any...I don't have 5.1 monitoring anyway.
I can see no mention of pitch for audio in the manual. There is 18 references for pitch as rotate.

If you want to try a 3rd party app, Wayne Norton's 'Dali' (PC) or V-mac (Mac) have a cute speed change facility which uses some neat processing to render 25p to 24P with or without speed change. We use it regularly for 25P>24P transcoding camera files. http://www.hdcinematics.com/

V-mac GUI

VMacMainUI.png (436.33 KiB) Viewed 14671 times

isn't fairlight capable to re-pitch an audio file?

This is the problem. You even don't know if it can. Another story is to know exactly how it does it
I would not test it with 5.1. Stereo is good for the beginning
In order to know if 5.1 is fine you need proper listening setup ( or you need to know that software is made and trusted to do 5.1 re-pitching).

I don't do audio, that is why i asked.
My assumption is that a professional mixing package should do it, and with professional quality... (like protools does)

Problem is that ProTools, WaveLab etc use MPEX, ZTX, ClearScale etc algorithms, which needs to be licensed (and they are not cheap as they represent top end solutions). Pitch correction is as difficult as motion adaptive framerate conversion, so you need to use very good method for good results. Multichannel audio brings another issue as you can't treat each channel separately- but you have to keep them in phase. If particular software doesn't support it then result will not be optimal.

If you want to try a 3rd party app, Wayne Norton's 'Dali' (PC) or V-mac (Mac) have a cute speed change facility which uses some neat processing to render 25p to 24P with or without speed change. We use it regularly for 25P>24P transcoding camera files. http://www.hdcinematics.com/

VMacMainUI.png

This is not going to do high quality pitch correction for 5.1 for sure. It's ffmepg driven, so don't expect miracles.
Do you actually know if it's doing pitch correction or just resampling?
If you have proper 5.1 mix which was done by some audio studio then I would rather not do pitch correction at all- it will be less damaging overall.

I was told of a 25FPS DCP that hit a cinema that could only do 24 so they played it 24. I am not sure how as I thought it would reject it. The director said he cringed all the way through it: noticing pitch and the slight slowness but he said that no one else appeared to notice.

I have avoided this until now but I have a client who needs to create a 24P for festival circuit. Anybody with tips and techniques to offer will be rewarded with that nice fuzzy warm feeling you get from knowing you have helped a colleague in need!

The best would be to ask if place accepts 25p DCP. Many places do these days. If you can avoid fps conversion then this is the best solution.

I was told of a 25FPS DCP that hit a cinema that could only do 24 so they played it 24. I am not sure how as I thought it would reject it. The director said he cringed all the way through it: noticing pitch and the slight slowness but he said that no one else appeared to notice.

And this is quite often "better" than trying to do pitch correction, specially crappy one.
Most DVDs in Europe are just speed up, without pitch correction.

I second this – at least for anything but productions aimed at an audience focused on music, like opera. Most other audiences won't notice and you avoid all the potential problems with surround phase. Or have it done by a facility specialized in such tasks.

BTW, "Titanic" was a few minutes shorter on European TV, but there was no censorship

Of course, the director would have noticed, having heard it all so many times.

I was told of a 25FPS DCP that hit a cinema that could only do 24 so they played it 24. I am not sure how as I thought it would reject it. The director said he cringed all the way through it: noticing pitch and the slight slowness but he said that no one else appeared to notice.

I call this ******** on theater: both player and projector will automatically sync at 25 of the dcp is such made...

Is not goddamn film.

You won't even notice 1fps difference. It's not 50 or 60p.
24p and 25p are basically the same for viewer- both are low fps with a lot of motion blur.

You won't even notice 1fps difference. It's not 50 or 60p.
24p and 25p are basically the same for viewer- both are low fps with a lot of motion blur.

It's the pitch of the audio the issue, not the video per se

If they "forced" 24p playback out of 25p master than yes- pitch will be affected. If resampling method is decent then it will be about the same as you doing it up-front. There won't be most likely pitch compensation, just speed change by pure re-sampling.
Sony SR decks offer playing back 24p/25p at opposite speeds, even have pitch correction setting (on some firmware), but it's poor quality and better to turn it off.

If they "forced" 24p playback out of 25p master than yes- pitch will be affected. If resampling method is decent then it will be about the same as you doing it up-front. There won't be most likely pitch compensation, just speed change by pure re-sampling.
Sony SR decks offer playing back 24p/25p at opposite speeds, even have pitch correction setting (on some firmware), but it's poor quality and better to turn it off.

I am not sure of resampling-it's just clocking the frames out at a different rate. I assume the audio syncs accordingly.

I recall the mid 90s (maybe a little later) when the Americans had big seminars at our local Sydney SMPTE conference promoting the virtues of the 24P Universal master. All other delivery formats would be struck from that: 23.nn, 29.nn & 25 fps. So the proposal was we would start making everything in 24P. A passionate old technician from the ABC (Australian Government broadcaster like BBC) got up and asked "How will we make the 24P into our 25fps for broadcast?" He was told: "simple, just speed it up by a frame a second!" well the guy hit the roof! He told them it was just aesthetically wrong: the actors performances are not true to the moment, their voices are different and the music is wrong. Thanks but no thanks!
In Australia, from the beginning of TV, we would get most US glossy programming on film and do just that - speed it up rather than standards convert and end up with pull down. I would have to retune my guitar to play along with the theme tunes.

You won't even notice 1fps difference. It's not 50 or 60p. 24p and 25p are basically the same for viewer- both are low fps with a lot of motion blur.

I have done many, many feature transfers where we output both 24fps and 25fps versions of the same film. The 25fps versions are too fast, altering the pacing and the timing of the cutting, and it's very noticeable if you're aware of the original film. 4% is actually quite a big change.

I concede that an audience that has never seen the original 24fps film and doesn't have that to compare to probably won't notice. The sound is a bigger problem than the picture.

If they "forced" 24p playback out of 25p master than yes- pitch will be affected. If resampling method is decent then it will be about the same as you doing it up-front. There won't be most likely pitch compensation, just speed change by pure re-sampling.
Sony SR decks offer playing back 24p/25p at opposite speeds, even have pitch correction setting (on some firmware), but it's poor quality and better to turn it off.

I am not sure of resampling-it's just clocking the frames out at a different rate. I assume the audio syncs accordingly.

...

I mean audio re-sampling to speed it up.
Video will use original frames, just played faster.

You won't even notice 1fps difference. It's not 50 or 60p. 24p and 25p are basically the same for viewer- both are low fps with a lot of motion blur.

I have done many, many feature transfers where we output both 24fps and 25fps versions of the same film. The 25fps versions are too fast, altering the pacing and the timing of the cutting, and it's very noticeable if you're aware of the original film. 4% is actually quite a big change.

I concede that an audience that has never seen the original 24fps film and doesn't have that to compare to probably won't notice. The sound is a bigger problem than the picture.

Yes, so time to stop this nonsense that USA can't watch 25fps originated content.
Hollywood have to also go further- it's not anymore 80s or 90s or even 2010

Now we have streaming services so framerate should not be anymore a "problem". Maybe it's time for TV manufactures (who seams to be running whole show now) to simply unlock 25fps in USA models. Somehow it doesn't bother them to have European models supporting 24p and NTSC framerates.

24p is always better choice when you are going to output to 35mm.
for DVD/Blueray mastering you can speed up your film (both video and audio).

If you work with FCP, you can always use Cinema Tools for this kind of conversion. It is fast and straightforward.

24p is always better choice when you are going to output to 35mm.
for DVD/Blueray mastering you can speed up your film (both video and audio).

If you work with FCP, you can always use Cinema Tools for this kind of conversion. It is fast and straightforward.

1) 35mm for distribution is dead. Sorry. I love film but is extremely unlikely you will eever see your movie in the treaters in that format.

2) dcp and projector play 25 just fine

Now we have streaming services so framerate should not be anymore a "problem". Maybe it's time for TV manufactures (who seams to be running whole show now) to simply unlock 25fps in USA models. Somehow it doesn't bother them to have European models supporting 24p and NTSC framerates.

American TV sets already can handle 25fps with no problem. At least, the sets I use and have seen.

When are we going to rise up and put an end to this nonsense?
I nominate 50P as the global standard......but can we wait until SSDs get a little cheaper?
I once heard a sage opinion that 24 wasn’t an asthetic, it was an “economic”: celluloid was very expensive and 24 FPS was as little celluloid they could get away with without making people sick.

And now there is a fairlight effect to pitch the audio?

And now there is a fairlight effect to pitch the audio?

I think elastic wave was there for a while, but it has been updated at some point in the last version or two with better more specialized algorithms for vocals/dialog, general purpose (music, Foley, SFX) and variable speed.

The audio panel in the inspector has pitch controls as well.

Pitch: Each clip has two pitch controls for altering clip pitch without altering clip speed. You can control pitch in Semi Tones and Cents.

Speed Change: Any adjustments made using Elastic Wave are reflected here.

Elastic Wave retiming is a fast and easy keyframe-based way of dynamically retiming audio, squishing and stretching different parts of a waveform to subtly retime audio playback for a variety of reasons, all while maintaining constant pitch. For example, if you’re using the audio from another take to replace that of the current take, but the performer’s timing is just a little bit different, you can use Elastic Audio to make small adjustments to retime the second performance to match the first.

When are we going to rise up and put an end to this nonsense? I nominate 50P as the global standard......but can we wait until SSDs get a little cheaper?.

Don't forget that 24fps has been the worldwide motion picture standard for almost 100 years, since the dawn of sound film in 1927. I think 24fps has a better look than 25fps, but I do film remastering for a living, and that tradition is important to me and the way I look at movies.

Well, I doubt that any untrained eye will really notice, as long as the shutter speed is right.

24 fps was an economical consideration. While silent film already showed the illusion of motion above 16 fps (often hand cranked, so around that value), 24 fps was introduced with optical sound. 24 fps was considered good enough for the sound quality, but not using too much footage per minute.

And a world-wide standard? Dream on. I'd already be quite happy not to see interlace any more.

Don't forget that 24fps has been the worldwide motion picture standard for almost 100 years, since the dawn of sound film in 1927. I think 24fps has a better look than 25fps, but I do film remastering for a living, and that tradition is important to me and the way I look at movies.

I posted my dismissal of 24FPS in 2017! I, in part, formed my opinion after reading a fabulous essay by a US cinematographer who explained that 24FPS was established after anything slower was found to make people sick from perceived strobing. (I can’t remember his name) Motion ‘resolution’ is improved by increased frame rate but motion blur is often lost and ideally put back to soften fast movement. What about 48FPS? Or just ditch all this new-fangled digital nonsense as we long for the purity of the past?

I don't think it was because of strobing, since any decent movie projector was avoiding that by interrupting the light beam at least two times, but normally 3 times per frame.

A Defense of 24 FPS and Why It's Here to Stay for Cinema

Don't forget that 24fps has been the worldwide motion picture standard for almost 100 years, since the dawn of sound film in 1927. I think 24fps has a better look than 25fps, but I do film remastering for a living, and that tradition is important to me and the way I look at movies.

I posted my dismissal of 24FPS in 2017! I, in part, formed my opinion after reading a fabulous essay by a US cinematographer who explained that 24FPS was established after anything slower was found to make people sick from perceived strobing. (I can’t remember his name) Motion ‘resolution’ is improved by increased frame rate but motion blur is often lost and ideally put back to soften fast movement. What about 48FPS? Or just ditch all this new-fangled digital nonsense as we long for the purity of the past?

I think it was more about actual smooth motion. Something which for the eye looks fine.

There are competing explanations for why 24fps became the established standard. The usual one is not visual, but the demands of sound: the optical track has its own requirements, for fidelity and synchronization, which a minimum of 24fps met.

Is there still raging debate over higher frame rates for movies? It's years now since some big budget filmmakers tried higher rates. Most viewers hated it. The added temporal resolution destroyed the dramatic/situational illusion.

Who is still flogging this one?

I've been doing this repeatedly recently for festival screenings and here's a simple reliable method.

Output a clip of the complete film/video. And re-import it into a bin.

Make a 2nd duplicate copy.

Next use Clip Attributes to change the frame rate of the original clip from 25fps to 24fps.

Drop this altered clip into a new 24fps timeline. The video should play instantly.

The audio won't be correct though, so delete the audio track from the timeline.

Now drop the second copy of the clip onto the timeline and delete the video track, leaving the unchanged audio.

Finally, use 'Change Clip Speed/Duration' and adjust the speed on this audio-only clip to 104.1667% (=25/24). You should now see that the video clip and the audio clip are the same length, and that the lip sync is perfect. (You can also type in the required duration to do the same thing and you can get this from your altered video clip.)

The point about this method is that the quick change to the clip attributes means that your 24fps timeline instantly recognises the video as being the correct frame rate, and it doesn't try to start doing lengthy calculations. Then it's a case of adjusting DaVinci's audio 'calculation' to match the video.

You can use the same method to adjust 23.976 to 24fps.

A nice addition from the Blackmagic coders, would be to automatic retime the audio in the Clip Attributes menu, when adjusting frame rates. Then this re-timing operation would take just a few seconds.

@paultom

You do know that if you create a project with the mixed frame rate preference set to "none", you can just drop your 25fps program into a 24fps timeline, and it will run (and export) at 24fps -- sound and image both? There is no interpolation and/or added or dropped frames, it's frame for frame.

@paultom

You do know that if you create a project with the mixed frame rate preference set to "none", you can just drop your 25fps program into a 24fps timeline, and it will run (and export) at 24fps -- sound and image both? There is no interpolation and/or added or dropped frames, it's frame for frame.

Excuse my ignorance John, but how does that work? How can it be "frame for frame" when 25fps is played back on a 24fps timeline?

Clock your frames out at 24 instead of 25 = 4%(?) slower = audio needs attention

but how does that work? How can it be "frame for frame" when 25fps is played back on a 24fps timeline?

When mixed frame rate preferences are set to "none", the timeline becomes a machine which only runs at one frame rate (set for the timeline), regardless of the original frame rate of the clip.

So, if you put a 120fps clip on that timeline, that clip will run at 24fps (slow motion). If you put a 12fps clip on that timeline it will run at 24fps (fast motion).

Clock your frames out at 24 instead of 25 = 4%(?) slower = audio needs attention

I doubt many people will notice a 4% pitch change on its own, if in the fact the system doesn't auto-correct for it (it may; I'd need to go back and check). But assuming it doesn't, you can change the pitch easily enough.

but how does that work? How can it be "frame for frame" when 25fps is played back on a 24fps timeline?

When mixed frame rate preferences are set to "none", the timeline becomes a machine which only runs at one frame rate (set for the timeline), regardless of the original frame rate of the clip.

So, if you put a 120fps clip on that timeline, that clip will run at 24fps (slow motion). If you put a 12fps clip on that timeline it will run at 24fps (fast motion).

Yes I understand that, but my question regarding 25fps playing back on a 24fps timeline remains. How is that possible 'frame for frame' as you describe without interpolation, dropped frames or some other form of truncation? There are 25 frames per second in the original clip, and 24 frames playback and render. 'Frame for frame', what happens to the extra frame?

Taking 25 to 24:
Frame 25 becomes 01:01 in 24.

Yes I understand that, but my question regarding 25fps playing back on a 24fps timeline remains. How is that possible 'frame for frame' as you describe without interpolation, dropped frames or some other form of truncation?

Sorry, but I don't think you do understand. Imagine a projector which works at only one speed -- 24fps. You have a movie that was recorded at 25fps. Same film size, same sprockets, but recorded at 25fps.

What will happen when you put that 25fps film in a 24fps projector? Will the projector interpolate the 25fps program? Will it add or drop frames to come out even? Or will it play back the program the only way it knows how - at 24fps?

When you select "none" in mixed frame rate preferences, that's what your telling the system to do. Ignore the original frame rate and play back everything at the timeline rate.

Exactly. You can tell easily, since it'll run a bit longer.