Audio imported from a video is different between DAWs - can anyone explain why?

Nuendo
#1

I’ve imported the same h264 .MOV video (with .aac audio) into every program I have access to and it looks like there’s up to a 2 frame difference between Nuendo 7 and Pro Tools. Picture here: https://imgur.com/O5UbIMa

My guess would be that it’s something to do with how different programs deal with compressed formats. I’ve noticed this happening with N7 a lot before so I always go by the AAF / OMF’s audio as being the true sync rather than trusting any audio imported from a video. Is there any reliable way of knowing which DAW is providing the most accurate decode of the video’s audio?

If you ever have to sync content to the reference track of a video how do other people deal with this sort of situation and how do you know which one is correct?

#2

There may be some clues here:
https://www.steinberg.net/forums/viewtopic.php?f=275&t=145539&p=782560#p782560

#3

Hmm yeah I did have a look through that but it deals more with video. Interestingly I just made my own test video (h264 .mov 128bit aac) and Pro Tools seems to be sample accurate with the original WAV whereas Nuendo 7 is a frame and a half off as you can see here: https://imgur.com/ZhYVNEh

I had a very professionally embarrassing day yesterday as a result of this issue. I was working with someone in Pro Tools and they were asking me to accurately sync things up to the reference track which I WAS as far as I was aware, so I looked like a total idiot. Apparently Nuendo’s accuracy with .aac audio from an h264 seems to be off for some reason - are they planning on fixing this in future?

#4

For what it’s worth I’d advise against ever using h264/mp4 video or any mp3/aac Audio ever, anywhere in audio to picture work. It’s too prone to exactly this kind of thing due as you said to the compression which literally breaks down the notion of discrete frames. This compressed audio also gives issues in video editing apps … it’s a delivery technology not a production format.

Ask for ProRes LT ( or Proxy) from your video source … most AV apps can export it even on PC where OS level support has been deprecated.

The video will play great, your audio will stay in sync … you won’t look back.

#5

I can’t repeat it enough.
There are 2 things that are crucial for anyone working in audio post.
(And that goes for the video editors as well)

2pop front and back (usually @ 48 frames)
BITC

Those two things will prevent any sync issue and guarantee proper sync throughout the process, from rushes to final master and pull.

I really don’t understand what is so difficult about it.

Fredo

#6

I mean on the one hand sure in a perfect world I can totally see where you’re coming from, but on the other it certainly seems like something’s not right and is worth pointing out if other DAWs can do this correctly? There are actual glitches in the imported audio of the latest video I’m working on - as you can see the start is chopped up and different to the (totally correct) Pro Tools import.

To answer your question, the difficult part is saying to clients, “I don’t use Pro Tools and sadly my DAW is not as accurate at importing audio so can you export out a reference WAV with 2 pops as well just to be on the safe side?” especially if it’s a short project or a quick 24hr turnaround where I don’t have time to explain what 2 pops are to an editor who’s never done them before

#7

Sorry man, 2pops (white frame for video editors) and BITC are standard procedure in audio post, no matter what DAW you are working with.
Asking for it (or better, making it part of your delivery specs) should make you look as a real porfessional, not the other way around.

Fredo

#8

Well this is a Nuendo forum, so really regardless of whether or not we ask for a 2-pop it would be better if Nuendo imported audio from a video file correctly, assuming there is such a thing.

If Pro Tools imports audio correctly and Nuendo doesn’t, then a 2-pop is a workaround. It seems absolutely fair to me to request Nuendo to do this right.

PS: I can’t remember the last time I got a 2-pop for TV shows. Fortunately I’ve been working 99% in Pro Tools recently so it hasn’t been a problem. ;-/

#9

No it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem, no it’s an industry problem

fade to black

#10

OK, so far for offering solutions and giving advice how to work around a problem.

This forum is meant to be a place where “users are helping users”, but if you prefer it to be a place just for complaining, fine be me.

Fredo

#11

Agreed.

I import the video, plus the OMF/AAF given to me by the editor that was exported from Premier Pro.

I don’t do any shifting. When I compare the audio from the video VS. the audio I extracted from the OMF, there’s at least a 2 frame difference.
When I play both, you can literally hear a doubling effect.

I figured it’s safer to keep the OMF audio files where they are, rather than shifting them, but I really don’t know.

Any ideas?

#12

Agreed! I used to think 2-pop was essential, nowadays hardly any of my clients really give a sh*t about it.
The point is, 2-pop doesn’t help with any sync issues. See my other message above. I don’t see how adding a 2-pop is going to help.

#13

Absolutely.

#14

That is unfortunate for both of you.
I insist having 2pop in the beginning and in the end. I would not work without. If someone refuses to put those in I have to ask why? It isn’t time consuming nor difficult. We use always self made white paper that gives simple but strict info about how video and audio must be delivered to us.

Also when making frame rate conversions, with these two 2pops I can make sure my conversions are spot on…
Bye / Tumppi

#15

Reason the more that you have to insist on it.

The point is, 2-pop doesn’t help with any sync issues. See my other message above. I don’t see how adding a 2-pop is going to help.

Mind me saying, you are wrong about that.

A 2pop is lined up with a white video frame @ 48frames before picture start and –ideally- 48 frames after the last frame.
So you always have a proper reference of audio vs. video.
When working with multiple people/studios on a project (Composer/sound designer/Foley studio/Remote Post-Sync/ADR) a 2pop is indispensable.
If there is one thing that is unreliable, then it is video length.
One editor delivers video from first frame, another one leaves a few seconds of black, etc … You can’t possibly know.

What if the picture starts with a few seconds black, or a fade in?
How can you possibly know where the first frame is? How many library music tracks have you seen which have a half- or whole- second of silence at the start, so that the music starts later than the video. That is what video editors do.

They are unreliable, and so is the reference audio that is included in the videotrack.
Logo’s, reference tones, countdowns, start- and end credits are added long after the final lock of the picture edit.
The Colorgrading and VFX people are also sending out video’s to different persons.
And most likely, these versions will not have the same length, because Titles, Opening Sequences, closing credits and other stuff is worked on by other people. And yes, someone will give instructions to another person using “another” video edit than yours.
So at one point many different versions of the “locked” video are circulating.

Just a month ago, I worked on a movie where the director has made a cue list for the composer using a video (without BITC) where a 5 second Billboard was added at the start. The composer was working on the same video as we had. (and has added a 2pop)
The poor man has composed his complete score to cues which were 5 seconds off.
I can go on for a while if you want…

So, please don’t tell me that BITC and 2pops are of no use.

Fredo

#16

Not really. I haven’t had a sync/tc/frame rate problem sneak up on me for a long time. I can’t even remember the last time it happened.

I don’t think either of us are saying that 2pops are bad or should be avoided or are useless or anything, I think the point was simply that it’s possible to end up in a situation where asking for a redelivery of something that already works fine just because you want a 2pop is going to make you look annoying. It would cause more work for the editor for what they perceive as no good reason. The fact that including the 2pop makes for some sort of insurance should something go wrong doesn’t change the fact that if everything is working fine then you asking for a redelivery is just you wasting their time.

I was personally just saying that I’ve had more projects than I can remember - on Pro Tools - where I received content without a 2pop and it all worked fine. On top of that deliverables for some content requires that there is no 2pop, and there were cases over a year ago when the video editor asked me in an annoyed way to re-export and send mix/stems back without the pops. But that’s really a different issue I suppose.

But ‘yes’, of course it’s a convenient and releatively easy thing to include on the timeline for the editor, and it’s very useful for us.

#17

I don’t read it that way. The way I read it was this:

  • Importing content gives a problem.
  • Having a 2pop shows that problem.

but

  • Having a 2pop doesn’t solve that problem.

In other words, a 2pop doesn’t help sync. It just makes it easier to see if something is off and by how much. Now, all a 2pop is is a piece of audio in an agreed upon location on the timeline. If you have one video file and you rip audio out of that file into different applications and the audio ends up in different positions then having a 2pop doesn’t make that not happen. It still happens. In addition to that you can still see it. I agree, having a common frame of reference makes it easier to line up the audio correctly, but the technical issue remains.

I think that was the point.

#18

Yes it does.

  • It shows that the import is wrong, and how much it is off-sync
  • It allows you to shift the audio to the place where it needed to be upon import.

Does ot solve the problem our beloved application has? NO
Does it offer a workaround for the problem: YES.

And that is exactly what this forum is for. Helping other people.

Fredo

#19

Okay, with or without the 2-pop, the main problem still remains.

imported OMF/AAF from Premiere Pro/FCP - is a few frames off, when comparing to the audio direct from the video. When playing both, doubling effect is heard.

But I choose to stick with the the OMF/AAF provides, rather than trust the audio from the video, like the OP.

What do we do here? Is this a Premiere Pro to Nuendo translation problem? Do any settings need to be tweaked in Premiere Pro, before exporting the OMF/AAF to a Nuendo user?

#20

Damn, haha that sucks.