How to sync audio and video from two different sources

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RobSab

New Member
I provide interpreting services. What this means in practice is that I usually have the following setup:

  1. video comes in via ndi and I pick it up in OBS Studio
  2. audio comes in via a third party application which automatically plays the source volume at 100% if there is no interpretation. If there is interpretation (source is in a different language then the one that we desire), we interpret and the third party application reduces the source sound volume to 30% and overlays the interpretation at 100% of the volume.
  3. I add the audio with delay or sync offset as it is called in OBS Studio (by trial and error) to get the audio and video in sync and then RTMP stream by language to required destinations.
Does anyone have a clever (more automated) way to get the audio and video in sync in OBS Studio in the scenario described above?
 
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Lawrence_SoCal

Active Member
Here is what I used for House of Worship streaming with NDI PTZ camera and a professional mixer. There are other ways, but in case you don't get a better response, maybe this will help. In terms of automation... I'm sure there is a way, but at what cost? and probably not with OBS. Are you willing/prepared to spend big $$$.

Streamgeeks https://youtu.be/LXY69tuBfV4
http://418770.hs-sites.com/sync-your-obs-audio-and-video
Download this video - https://www.dropbox.com/s/w4z6e6z0nwy0h87/Audio Video Sync Test done.mp4?dl=0
Here is the guide - https://www.dropbox.com/s/aokyu48jy9ma26d/OBS Audio Syncing Tool.pdf?dl=0

I put the test video clip on a tablet, and filmed/mic'ed the tablet, and then record in OBS. I can then adjust manually from there.. not elegant but free
 
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RobSab

New Member
@Lawrence_SoCal thankyou. I appreciate your input.
Actually I have become pretty good at lip reading and adjusting the delay in the audio in OBS.
My challenge is that I need to adjust the delay several times during an 8 hr conference as it drifts backwards and forwards depending on changes in latency within my network (ndi in use) and for latency in the global Internet / ZOOM network / processing data centres etc........

I have heard of having a 20kHz generator sending a sync "beep" every 5 minutes and a pixel generated at the same time in a frame and these two pieces of information are used to automatically sync the video and audio..... but have not come across anything like this in the $$$ range that I would consider as viable.
 
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RobSab

New Member
Brilliant Fbosman. Not a Mac person, but will look for an equivalemt on Android.

Edit: Found an Android APP AVSync - will test it and give some feedback.

Robert
 
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