Question / Help Audacity & OBS audio drift out of sync.Why?

Gaz

New Member
I record audio commentary with Audacity and gameplay with OBS.
OBS records 2 audio tracks : the game audio and my microphone, so that I can sync up the microphone recording from Audacity by simply overlaying that track in Sony Vegas Pro when editing the video.

I count down and do a tap to sync up the audio perfectly at the start of the video. However after mere minutes the audio track that was recorded with Audacity will start drifting out of sync, with a recording of 20-30 minutes it can get as much as a full second or more out of sync.. The audacity track will start getting ahead of the OBS recording. It either starts going faster, or the OBS recording goes slower.

Audacity is set up to record at 48khz with 32 bit-float quality. It is suggested to leave it at 32 bit for editing purposes and then export it into a .wav 16 bit file.
OBS records the video on CBR at 30fps and the audio on 48khz with a 160 bit rate (this audio gets muffled anyway, so the quality here is not important). I'm not sure if OBS records in 16 or 32 bit, I can only assume it's 16.
Sony Vegas Pro is set up to use 30 fps and 48khz.

I am not sure what I am doing wrong or what could be a possible cause of the 2 audio tracks drifting from perfect sync to out of sync. As it stands currently I am spending forever splitting my audio track and moving it around manually to keep it synced up with the recorded game audio&video from OBS.

Please help :)
 

Gaz

New Member
Yes, I use Audacity to record microphone audio because of all the editing you can do in Audacity.
Noise reduction, bass/treble boosts, normalizing audio levels, hard limiting, compression, etc.
It's really easy to use and produces great audio quality and OBS simply doesn't have that capability.

With OBS I've realized it sometimes doesn't even pick up my microphone audio.


Regardless of that though, I just don't understand the technical aspect behind this sync issue.
I can sync it up perfectly in the beginning and then at the end of the track it'll run a second or two ahead of the OBS track.
I've tried simply stretching out the track to make it the exact same length as the OSB track, but then other areas will go out of sync.

What could be the cause of that?
 

Simes

Member
It could be caused by errors in the recording, which (as I said) I've experienced with the Media Foundation audio encoder OBS uses by default. I'd recommend installing the CoreAudio encoder and seeing if that fixes it.
 

ooftv

New Member
This can happen if your video is dropping frames. One way to troubleshoot is to find out when it first starts losing sync and see what's happening there.
 
hey man, having your exact same issue here.
I record on two separate channels piano + vox for tutorials
A workaround could be:
1) record everything in OBS
2) import the recording in your video editing software
3) extract audio only before doing any video editing
4) import that audio in Audacity
5) do all the fixing and corrections Audacity enables you to (which I agree, they are awesome)
6) get rid of the old audio tracks in the video project and substitute with the fixed audio track exported from Audacity

hope it helps
 
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