Sync Issues!!!!!!!!!!!

Hey All,

I’ve been given the task to sync an audio description version of a show to picture. The original video file has been sent to me as an MKV file and I’ve been sent a seperate WAV file which features the added audio description. After Muxing the file with MkvMerger the audio gradually goes out of sync.

I exported the original audio from the MKV file using VLC Player and imported both audio files into Cubase. I noticed that audio description file is about 20 seconds shorter than the original audio.

I tried time stretching the audio description wav but it didn’t seem to work either.

Any ides!??!

Hi,

Make sure, you set the same sample rate of your project, of the WAV file, and of the audio part of the video file.

And then, make sure, you set the same frame rate in the Project Setup, as the frame rate of the video is. You can easily get the Frame Rate from the Video, in the Project Setup.

Hey Martin,

I tried the standard sample rates that the file could be. I’ve had similar issues where a file header has the wrong sample rate than that the file was currently in. The way I solved that before was some combination of importing the file into a project with a given sample rate without allowing Cubase to convert the file. Then Changing the project sample rate and allowing Cubase to convert it, which treats the file as the current project sample rate. Very confusing but that normally works.

This time that solution doesn’t seem to work. I think the likely answer is to use the ‘process>re sample’ option with the correct % value. I worked out the % difference in length of the two audio files. This produced a closer match to the original, however it still went out of sync. But… (it may be my imagination) it seemed to take longer before the sync issue became apparent.

My question is now… How could I go about working out a closer % for the re-sampling? I’ve uploaded the two audio files as this may make it easier for you to understand. You can download the WAV files here: https://drive.google.com/file/d/0B4kl1vEOrG7lZXNfVmEyb205VXM/view?usp=sharing

Thanks for you patience everyone!

P.S. Things I know: Video is at 25fps with audio 48k, Additional WAV is at 44.1. I believe both audio are in 16bit.

Hi,

OK, if you have different Sample Rate of the original video, and the WAV file, you have to resample it. So I would recommend to do it this way:

  1. In the Project Setup [Shift + S], set the Sample Rate to 48.000 kHz.
  2. Import the video file with the audio (which is 48kHz).
  3. Import the WAV file.
  4. In the Import Options dialog, Cubase will ask you, if you want Convert to Project: Sample Rate (44.100 kHz to 38.000 kHz).
  5. Enable this option, and click OK.

Now, your WAV file is in the same sample rate as the video source sound track, and it should be completely in sync.

If you can affect it, I would rather recommend to already export the WAV file as 48kHz. This resampling decrease the sound quality.

Does it work to you?

Hey Martin,

Afraid that didn’t work. The file says it’s in 44.1 but I highly doubt that to be true. When I up-sample it to 48 using the method you have described it is about 20 seconds shorter than the original video file after I have lined up the first sounds of each file. It’s only after about 10-15 seconds when the audio becomes noticeably out of sync with the original audio file and video. I have managed to cobble together a solution, however it is by no means perfect and I’d really love to know the quicker and more accurate way of solving similar issues for the future.

The only way I managed to solve it was to cut the video up into 5 second clips at the very start of a spoken line or loud sound and line up the wave form. Then crossfade it with the previous clip. For an hours worth of audio you can imagine that took some time.

In general, most of the audio sync problem arises from the time axis damage. Check this article and learn more about how to Fix the Problem of Audio not being in Sync with Video