24p to 25p?

[Jayo2007]

Thanks for the fast reply. So by speeding up the audio and dropping the pitch I can keep the same duration of the audiotrack? It feels like i’m missing something. Since the image is projected at 25fps instead of 24fps, the duration of the video will be shorter, right?

[Jayo2007]

I’m sorry but I’m still very confused about the audio. In another forum I’m told that I can use the original audiofile (a music track) and that it’ll match up with the conformed 25fps footage. But I can’t see how that’s possible.

If I have a 1 minute song, with 24fps video to it, and then conform to 25fps, the video and the audio will speed up by appox 4%, correct? Which mean that the conformed video footage will have a shorted duration than earlier, and not match up with the original audio. Or am I wrong (again)?

[Peter Dewit]

Have you tried just doing it first? If the program is that short the sync loss is going to be pretty minimal.

I’d make a backup of everything before conforming stuff just in case

[Jeremy Garchow]

[jayo2007] “If I have a 1 minute song, with 24fps video to it, and then conform to 25fps, the video and the audio will speed up by appox 4%, correct? Which mean that the conformed video footage will have a shorted duration than earlier, and not match up with the original audio. Or am I wrong (again)? “

Nope, you are totally right. So, since most people won’t miss or notice change in duration, they might pick up on the difference in audio pitch (since after all, the music is king in your video). So what you can do is pitch down your conformed audio, or take your 24p audio and speed it up 4% and while keeping the pitch. When you conform to 25p using Cinema Tools, the audio will get sped up (therefore pitched up) and resampled to 50.050 kHz. So if you hand this off to an audio house for a pitch down, make sure to alert them to that fact. Or you can do the pitch down/resample yourself in Soundtrack Pro and your mileage may vary.

Jeremy

[Gary Adcock]

[Dave LaRonde] “When European film makers — guys like Truffault, Bergman and Fellini — wanted to show their films on… oh, let’s say Deutsche Welle, you know what they did? They projected their films at PAL’s 25fps. They dealt with it. They lived with slightly off-pitch audio. “

Dave
you do not work in PAL -and since you have said prior that you have never shot 25fps film you should be careful.

In film projection the Audio is Not part of the film projection, it is delivered on a separate disk and sync’d with a timing track for the projection, so there would be no need for the audio to playback off speed.

Films in Europe are not shown at 25fps, they are shown at 24.o fps the same as it is here.
35mm and 16mm film is often shot at 25fps for direct conversion to when the output is for commercials or episodic work. Theatrical work for release is not ever shot at 25.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows

[Bob Flood]

Gary

isnt that DTS? ie one of the several digital film sound release formats IS a seperate disc, actually a CD.

but other formats, like dolby, are digital optical tracks printed on the film.

or has a sperate sound file on disc replaced the “interlock mag” of yore

just curious, as its been a while since i had to print a film.

“I like video because its so fast!”

Bob Flood
Greer & Associates, Inc.

[Michael Gissing]

I have MPEX3 software on a Pyramix system that does pitch/length conversion extremely well. I haven’t tried the tools in Soundtrack Pro.

For a short video the change from 23.98 to 25 is a whisker over 4% and the pitch correction is approx three quarters of a semi tone. I would advise talking to sound post people about doing the soundtrack correction, not trying to do it FCP.

Sync will not hold in spite of a previous comment. Every second it goes out by one frame. One long form projects I have had to calculate 23.98 to its real value which is more like 23.9759xxx. It took six decimals to make sure that the program remained frame accurate over two hours (Farscape the Movie).

And to clarify Dave & Gary – PAL broadcasters in my experience ran 24 frame prints at 25 for broadcast with the pitch going up uncorrected. Cinemas run at 24 in PAL countries.

[Jayo2007]

Thanks for all the support. I finally got a chance to mess with Cinema Tools. Well, after conforming the footage to 25fps, the duration of the file is now about 9 seconds shorter than before.

So what I have to do with the audio is to correct the pitch with approx three quarters of a semi tone? What’s happening with the duration of the track?

How do they, let’s say, send Britney Spears new video to play in the UK? (assuming they shot in 24p)

[Michael Gissing]

Most clips that I see coming from the US into Australia are converted from 29.97 or 23.98 to 25 via a device like a Teranex that creates a PAL 25 frame version the same length (and therefore pitch) of the NTSC. These devices do this by creating hybrid fields & smart frame interpolation.

The approach you have taken is to varispeed the frame rate up. If you want to do that and correct the pitch then that is one way, but to answer the question, what normally happens, the standards conversion is not done as a varispeed.

[Jayo2007]

I’m just exploring all the options. And still up to this point I can’t see how the speedup process would help me since I’m working with a Music Video where the audio has to stay original.

So besides the speed up process, what’s the smartest solution. Buy Nattress and go crazy with the settings?