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Audio out of sync with video

I am having audio matching video over a live stream. Any suggestions?


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Hi Michael,


Thank you for reaching out to us for some suggestions on A/V sync issues.


So this can be a tricky issue to solve depending on the exact setup that has been deployed.


I will do my best to address this from a generic point of view to try and assist.



As this issue is not uncommon most production software & hardware has an option to adjust the Audio and Video sync using a delay.


Note: Different production solutions may title this option in different ways... "A/V Sync", "Audio Delay", etc... 


This setting often asks you how much delay, in msec, to add to the audio feed which is great because we can make micro adjustments to try and synchronize the A/V.


But this often raises the question, for a lot of users, how much delay is there that I need to add without just randomly guessing...


In the following link is an example, using OBS as the platform, on how to take an instantaneous measurement of the delay.


StreamGeeks OBS Audio Sync Tool: https://streamgeeks.us/how-to-fix-obs-audio-and-video-sync-issue-with-a-new-tool/


Note: In IP environments this delay can change with time but the measurement taken will help to minimize the overall / average delay


While possibly not specific to your setup the overall information is applicable to a variety of platforms



Note: Our support team is always available during regular business hours to assist using their knowledge of the specific software & hardware you have and what has been known to work best for our clients using similar setups to eliminate or minimize the synchronization issues you have noted.



If there is any additional support you believe we can offer via the forums please don't hesitate to come back.

I also started having audio sync issues after I did the latest upgrade (the one that includes freeze image)…and it’s a progressive issue. When we stream ( using VLC)…at first it starts in sync at about 20 minutes it starts coming out out sync by about 500 ms..by the time of 30 minutes,it’s at least a second out..by 60 minutes it’s a full two seconds out of sync? Any ideas?

Hi Omar,


This document should go over most of those issues. https://help.ptzoptics.com/support/solutions/articles/13000083024-synchronizing-multiple-ptzoptics-ip-video-streams-audio


I would make sure the cameras have the most recent firmware and make sure to use NTP functionality to keep the cameras in sync with each other and keep the latency set in a more manageable spot. 


https://ptzoptics.com/firmware-finder/

Andrew Thanks for the documents. I have found a work around…the issue is this..I have running VLC version 3.012. which was the latest version. All was well. I then did the camera firmware update (the one with the freeze image update). So..I did a 30 minute test using different set point and enjoying the freeze mode update. In the following Sunday I did the normal recording as in the past. I transferred the VLC file to a portable hard drive and gave it to our editor of videos. She gave me a call and had me look at the 46 minute mark..the audio was lagging, but only slightly noticeable to the trained eye. She then had me look at the 51 minute mark. The audio had now started lagging by a 1.3 seconds, and from that point on lagged by 4.2 seconds at the end..65.3 mark. At this point I went and did the normal checks; making many videos..with no success.. I didn’t want to “undo” the camera firmware update, then I went a different route after searching many internet sites professing almost the same issue. Some folks undid the firmware upgrade..with success, but as I said earlier I wouldn’t do this . The other “correction” was to roll back the version of VLC. Most of these people had mentioned the were using OBS (I am not) but later found out the OBS uses “VLC” in this app. Very long story short, I rolled back VLC releases until I found one that worked (this took a huge amount of time as my issue occurred about 46 minute mark)…Ultimately found VLC version 3.010 worked!! I just reviewed our 68 minute service and found zero(perceptual) lag in the audio . While this is a “true” correction, maybe y’all can put my issues in a magical bag,and throw me out a solution. I do want to keep all my software current. And as I said earlier, I had no issues using the latest VLC revision 3.012, UNTIL I did the camera firmware update. Thanks again for all that you do for this customer. You have a blessed day, Omar Simpson

Hi Omar,


Yeah OBS does leverage VLC, I didn't even think the issue could be the VLC version though. I'll keep this in mind for future customers with the issue and let the rest of the support team know about this one.  

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