[SOLVED] Video Import Export Audio is asynchronous

Hey guys!

I have a problem with the built in “Video Export” in Nuendo.
When I do an Video Export and an additional Audio Export (WAV 48kHz 24bit), and then import the video and the bounced audiofile again,
the extracted audio track from the video is not a 100% synch to the original exported audio file. Also the length of the extracted audio from the video is not correct! It is about 0.5 to 1 frame longer than the video / original exported audio file. What’s wrong here?

This is a more serious issue when I convert the exported video to a smaller, more compressed video file. I use XMedia Recode to do so.
Importing the smaller video file results in an even more asynchronous result. There is a difference from 1 to 1.5 frames!!!

Can anybody recreate this issue or tell me what’s the problem here?
Thanks in advance and all the best

Here is a picture from an imported H.264 / AVC (30fps) video in Nuendo and ProTools.
The video is exactly 35 seconds long. In both DAWs, the extracted audio doesn’t match the correct video length, but in ProTools the waveform seems to end correctly, whereas in Nuendo the waveform is longer than the video itself.

Never work with H264, not in Nuendo, not in ProTools or any other workstation.
DnDx, ProRes and Photo Jpeg are the only codecs that guarantee you frame accurate sync.

And embedded audio can NEVER be used as reference.

Fredo

Hi Fredo,
thanks a lot for your fast reply.
Yes you are right, this problem does not occur with DNxHD or ProRes. But most of the times, production companies just deliver small crappy mp4s or movs as h.264… unfortunately
But yeah, lets say this issue is solved when you work with these lossless codecs.

But one thing still remains. In the end, lots of the stuff gets finally rendered to this smaller compressed codecs for web (social media, youtube, etc…).
So in this case, the audio track gets asynch again, or?!

Or is this just a rendering / “codec interpretation” problem of DAWs, when importing these compressed videos / codecs?

Thanks

Will try to explain, but will have to cut corners.
Audio needs to be offsetted in compressed video.
During playback of a compressed video, the audio lags behind.
So there is an offset applied to the audio during playback. And during playback only. When stopped, the audio should also be in sync.
The amount of offset applied during playback depends on the playback machine.
So it’s unpredictable. There are settings and ways to compensate and/or limit the problems, but we (the end users) can’t possibly know if it was applied and applied correctly.

So, the only way to work correctly in a DAW is to convert the video to a correct codec and import the audio from an AAF/OMF.
Or have a 2pop & white flash rendered with the video.

Then you can work properly in syc.
To deliver to the client, convert your HQ video back to H264 and you will stay out of trouble.

There simply is no other solution.
If you can make it work with H264 material, the it is purely a question of being lucky.

Here’s a great (the very best) tool to vconvert your video’s.
https://audiospot.audio/audiospot-creativetools
There is also a good reading about the sync issue somewhere in the documents.

Good luck!
Fredo

thank you very much!