Export longer than film

Nuendo
#1

Hello,

can someone explain the following. I am working on a feature film. The mp4 of the film is exactly 01:28:44:10 long at a frame rate of 23.98fps. Everything is at 48kHz of course. I have exported a stereo downmix of this film and send it to the editor. He complained that the wav file is a bit longer than the film and therefore out of sync. And indeed the length of the stereo wav export is 01:28:49.741 (741 being ms). However, when I import this stereo export into my Nuendo session, it syncs up exactly with the length of the film. Where do the extra 5+s come from and go respectively?

Best wishes,

Max

#2

Does the editor use FCP 7.x ?

#3

Hi Max


Where do you read out this numbers? I take it that on Nuendo tracks picture and mix have same lengh. Which one?
Where do you read the other lengh?

Oswald

#4

Samplerate mis-match.
If the movie has BITC (which it shouldalways have), then there can be no discussion about file length.
Movies says it is xxx-long, and audio is also xxx-length.
If it doesn’t line up at someone elses place, then it is not your problem. (So to speak)

Fredo

#5

ok thank you for your replies. The Movie has BITC. And within Nuendo everything syncs up. So even if I re import the stereo export, it syncs up. What I do not quite understand is, in Nuendo the film and the stereo export is exactly 01:28:44:10 long. But if I am opening the stereo export with a different program, like say snapper or quicktime outside of Nuendo it says the length is 01:28:49.741. Where do these extra 5+s come from? And why do they disappear again when I import it into Nuendo? Seconds should be seconds, whether I divide them into frames or ms.

Thanks!

Max

#6

This 5 sec sort of reminds me of 23.98 fps versus 24 fps on a lengh of 90 min. Is Nuendo giving it to you in 23.98fps while other systems are not able to give 23.98 and give it in 24 frame?

Oswald

#7

I see, that is a good point. I just notice that the mp4 file of the film played in Quicktime is also 5s longer. So maybe Quicktime is playing it in 24fps. But why is the stereo wav export on its own, outside of Nuendo, 5s longer and then 5s shorter within Nuendo? Wav is based on sample rate not frames?

Best wishes,

Max

#8

I agree that it’s probably a frame rate issue:

Dividing the longer file in seconds (incorrectly rounded) by the shorter; 5329/5324=1.0009
Dividing 24/23.98=1.0008

So that’s a pretty close value, roughly rounded, and not accounting for just how these frames are allocated specifically (because I just don’t know). But it’s certainly closer than 48/44.1=1.088.

If you are in Nuendo and select import audio and navigate to the exported file and select it (but don’t import it), does it give you the longer duration or the shorter? Just trying to figure out if there could be a problem with how the other programs measure the file rather than Nuendo…

And lastly, if you pick a different non-compressed file format, does the length still vary?

#9

But why is the stereo wav export on its own, outside of Nuendo, 5s longer and then 5s shorter within Nuendo?

I can not explain that, as Frame Rate is not even part of BWav Metadata…A far as i know Quick Time Player can not even know that it is generated in a 23,98 session.

Who exactly outside Nuendo is telling you that the file is longer? The audio file, independent of picture?

Oswald

#10

Hi Mattias,

If I go to import and click on the file, it says that the file is 01:28:49, so again 5s longer. But if I then go and import it into Nuendo, and I just tried it with a completely fresh session, it is again 5s less. I don’t understand this. So this is Nuendo itself giving me a different length when importing than when it is in the session.

Best wishes,

Max

#11

Exported at the wrong samplerate?
System clock not correct?
Session Pulled by mistake?


Fredo

#12

+1 to Fredo’s questions.

#13

  • I have exported it at 48 kHz, same as the session. I have also exported it now more than once, with the same result.

  • System clock? I am not syncing it with any other devises if that is what you mean.

  • session is not pulled, I checked that first. But if it was, wouldn’t that mean that the file after I re import it would be longer?

I actually don’t think that this is the issue with the editor though. He now told me it was only a few frames longer in his session. So maybe that is a problem on his end. It looks like that Mac os is interpreting the length differently from Nuendo. The only thing contradicting that narrative is that Nuendo also showed the file to be longer during import. But maybe it takes the length from Mac OS somehow?

Best wishes,

Max

#14

And you’ve tried different file formats? I mean, could it be that somehow the header gets messed up by a different application?

#15

I have tried MP3 and Wave, both with the same result. And the film file that I got from the editor also is 5s longer outside of Nuendo. And it is also 5s longer as it should be according to the editor. So Nuendo gives me the length that should be correct.

#16

There are plenty of “area’s” in Nuendo (and other applications) where you can check the length & framerate of the video. What does the Original video say in the Pool? according BITC? In QT? In G-spot or another application.
What doesyour audio shows in these same area’s?
Import audio from video file. What is the information of that audio file?

If there is a difference between your exports and the stuff you received from the editor, then something is wrong with your system/setup. This really sounds like you are clocked to the wrong samplerate. Which is possible since you are not using a House/Sync clock. So gather all the information you can, and compare the stuff you have been receiving with the stuff that you have send back.

Fredo

#17

The Pool tells me that all these files, including the original video, which is obviously not my export, are 5s longer than they should be. But the timeline of Nuendo says something different.

How can I be clocked to the wrong sample rate? There seems to be two ways I can set a sample rate. I can set it on my fireface, which is set to 48kHz, and in the project setup in Nuendo, also set at 48kHz. And if I was clocked to the wrong sample rate, why does it only matter in this project? I just exported and delivered a set of audiofiles for another feature film. They all had the correct length, were synced correctly and passed the QC.

It looks to me like all these files have the same length. The length is just read differently by different programs and even differently by Nuendo, depending on whether I look it up in the pool or in the timeline. How is that possible? The most consistent reading is the 5s longer version. Even the original film file from the editor is read as 5s longer as it should be. The only thing that is reading it at the length that the editor tells me it should be, is the timeline in Nuendo.

Best wishes,

Max

#18

Can you maybe post up the files for us to double check? Like one file which is correct which is then imported into Nuendo, and then one that has been exported and is then incorrect… So we can make sure if it’s Nuendo or your system or the files…

#19

Ok, here you can download the left surround channel of the film.

https://mab.to/gvWyVs6PAYN

MacOS tells me that it is 01:28:49:741 Long. If I import the file into a Nuendo session with 48kHz and 23.98fps it is 01:28:44:10 long. So is there anything wrong with this file? Would be good to know what you think the real length is.

Thanks,

Max

#20

Ok, I’ve tested a few things now:

1: In Nuendo 7.1 the import dialog tells me it is “1:28:49”. I imported the file and placed it exactly at 01:00:00:00, and the end of the file is 02:28:44:09.79. Length is thus exactly 1 hr shorter in Nuendo.

Windows Media Player ends at 1:28:49, same in
VLC media player ends at 1:28:49.

I’m seeing exactly what you’re seeing…

2: I opened up a TV post I did that read 53:11 in VLC, and it reads 53:11 in Nuendo’s import audio dialog box, yet if I place it at 1hr it ends up finishing at 01:53:08:01. This was a file that was delivered to the production company so I opened up that project again and it does indeed read 01:53:08:01.

3: Last thing I tried was to re-export using “insert broadcast wave chunk” which made no difference.

So I don’t really know what’s going on here.