NDI Camera Video and Microphone input will not sync

[Commdir-SJV]

I am using the most current version of OBS and the NDI-Tools v6.2 in Windows 11 Pro. I have two NDI cameras on the local network (hardwired, not wifi) and a microphone feed that comes into the PC via a usb port. The cameras, the PTZ keyboard controller, and the PC are the only devices on the network.

The audio is always at least 1 second ahead of the video. I have set the cameras to every setting for buffering from standard to none. I have set the sync from Source to Network. In all situations, the video is consistently around .75 - 1 second behind the audio. The delay is the same whether I am streaming or recording locally.

I thought it might be something with the system time of the cameras and the windows PC, so I set the PC up as an NTS server. The cameras and the computer are exactly synced from a system time standpoint. That also made no difference.

Am I missing a setting? Is anyone using the same type of equipment or settings that perhaps has solved this issue? All the comments around syncing seem to be the sampling rate of the audio and video, and I could understand how this would be the issue if the sync came and went. But not consistently off by the same amount over the entire recording / stream.

 

[Mikheil]

If the delay is constant (audio always 0.75/1 second ahead of the video), you could try slowing the audio down to an average value between 0.75/1 second. If the delay varies significantly over time, however, it might be more difficult.

 

[Lawrence_SoCal]

Audio, on separate data path, if orders of magnitude less computationally complex to process, so getting ahead of video is to be expected (completely normal and natural ... long documented).

Your options - combine audio into video before it gets to OBS Studio computer, or set up a sync adjust.
As alluded to above, if sync variance is constant, this is easy to address.. Personally I used https://streamgeeks.us/fix-audio-sync-issue-in-obs/ but there are plenty of other approaches. so use what works best for you
if the sync varies, that 'tends' to indicate an overloaded computer (could be background processes, or ??)