Conforming 23,976 to 25

[Alexander K]

Hello,
i'm trying to conform my 23,976fps sound master to the 25fps video my client gave to me. I used a few apps and plug-ins with no luck. Maybe somebody knows a better solution.

My first try was DIGIRACK Time Shift Plug-in with the appropriate Maintain Pitch preset. The resulting audio clip did have nearly the same duration as the video clip (1 frame drift). Then i typed in the exact duration of the video to get a 100% result. But both audio clips were out of sync.

Next try was X-form. Same relusts.

Then i imported the sound master into Pro Tools with pull-up sampling rate. This worked perfectly. The audio clip has the same duration and is in sync with the picture.


So why didn't the plug-ins produce synchronous sound? Was it maybe because of a wrongly conformed video? I think the plug-ins use linear speedup algorithms but i'm not sure it that is also true for the picture conforming. Maybe they speedup the picture not linear …
I also wonder if it's common to use a pulled-up master? Do i have to pitch it down by 4,267% ?

cheers
Alexander

[nucelar]

Then i imported the sound master into Pro Tools with pull-up sampling rate. This worked perfectly.

Because it's the only technically right way of doing it.

25 fps / 23,976 fps = 1,04270937604271

48000 kHz * 1,04270937604271 =50050 kHz

Unless the plug-in has the ability to consider all that decimal numbers, it won't be perfect.
Once imported, you can do a pitch shift if it's needed.
Conforming a video from 23,976 (or 24) to 25 has no secret really. It simply changes the framerate info in the quicktime header, and as a result it plays quicker, it is linear for sure because nothing is done to the frames.
Cheers

[Alexander K]

Hi and thank you.

I'm still confused about the way they speed up the video. They told me that they exported frames instead of a video file and encoded this folder of frames to a new video file with the new frame rate.
Don't know anything about this so maybe i misunderstood it.

Anyway. It's sync, it sounds right after the pitch down and so i'm happy with it.

Thanks.

[D'Animation]

Originally Posted by Alexander K

Hi and thank you.

I'm still confused about the way they speed up the video. They told me that they exported frames instead of a video file and encoded this folder of frames to a new video file with the new frame rate.

They are probably working with image sequences over QT's - thats the way our guys do it and its quicker that way than a complete rendered QT