Question / Help Echo'ing audio / delay of one audio source

[mpi-jakob]

Hey all,

I am working in a research instutite and we are currently preparing a study. The setup is the following:

Windows PC with
- two PCIe DeckLink HDMI Recorder cards
- two GoPros attached
- OBS Studio running

We are recording the GoPro's two video singnals into one video. When we start recording, the audio is sync. After a couple of minutes the audio is not sync anymore and we hear an echo. Disabling one camara's audio helps, but also decreases audio quality in generel because we need the to mics to get a good recording.
Restarting the OBS Studio helps for the moment until the problem comes back agian.

I also swithed from 44kHz to 48kHz what seemed to help. But the latest recording still has the echo in it, even it has been recorded with 48kHz.

Does anyone has an idea where this delay comes from and how we can get rid of it?

Thanks a lot!
Jakob

 

[Beardedbob]

Hi Jakob,

Could you post the OBS log, you can find out how @ https://obsproject.com/forum/threads/please-post-a-log-with-your-issue-heres-how.23074/

 

[mpi-jakob]

Dear Beardedbob,

thanks for your help.

I've attached two log files where we used the same settings for recording.
ECHO.txt is the latest recording with the echo
NO-ECHO.txt is a working recording just a couple of days before the last recording.

Thanks again,
Jakob

 

[mpi-jakob]

Dear all,

I have more information. I just got a new computer here for our lab and installed windows and obs freshly. And unfortunately, I'm experiencing the same issue. This time, I went to Windows 7's Recording Devices while OBS Studio was opened and enabled "Listen to device" for both Blackmagic Audio devices. Whenenver OBS is opened now, I can hear the GoPros through my headphone. Once I close OBS, they stop playing.

It turned out, that when ever I start OBS, the audio delay between both GoPros is different. Sometimes there is no delay, sometimes just a litte bit, somtimes a few 100 ms.
A workaround for me is now to start OBS Studio so many times until I have no delay. But this not really convenient.

Does anyone has an idea where this delay comes from?

Thanks,
Jakob

 

[mpi-jakob]

Ok, sorry. It turns out that the delay I can hear when I use the recording device "listen to" is not related to the delay in the video. Even if I can hear a delay through the "listen to", there isn't necessary a delay in the recorded video.

But still: same settings. Sometimes there is a delay, sometimes not.

// Edit: Another thing I was able to do is to add two "Audio Input Capture" to OBS. Doing this results into the same audio delay in video like I can hear with help of the "listen to" function.