Split Stereo NDI audio into 2 mono tracks

[Skutov]

Hi all,

I'm having some trouble figuring out how to achieve something and would like some input.

I have an AVMATRIX PTZ camera outputting and NDI feed of video with embedded audio, the audio comes from an audio input jack on the camera and has a stereo audio feed. This stereo feed has 2 microphones feeding it, one on the left channel and one on the right. I want to split this stereo audio feed into two seperate mono tracks within OBS so I can mix them seperately.

I have found this thread which discusses the effect I wish to achieve but does not for for an NDI source because the NDI source does not appear in the audio devices list.

Can anyone help me figure out how to achieve this either using OBS or another external program to route/split the audio.

Thanks in advance,

// Skutov

 

[AaronD]

Same hack as for any other stereo source that you want as dual-mono: make two copies of it, set both to mono, and pan/balance them hard to either side.

That works because the mono switch is *after* the pan/balance, which is backwards from pretty much every pro rig, and it means that they're both stuck in the center because the pan/balance is already tied up to separate the channels in the first place.

If you want anything different from that, you need to do it outside of OBS and bring in the finished result. At that point, you might as well do ALL of your audio work externally, and bring the final soundtrack into OBS as its ONLY audio source, to pass through unchanged.

Then the problem is getting NDI into that external tool. You might have to dedicate OBS's Monitor to that alone, feeding a loopback that goes to a DAW, then the DAW separates the stereo feed and does everything else, and then the final result goes through another loopback, back into OBS to pass through to the stream and recording alone. If you use headphones or studio speakers, those are fed directly from the DAW, not OBS.
Likewise if you replace the DAW and loopbacks with a physical console and USB line-in/out.

 

[DRI374]

Did you find a good solution for this? I'm in the same boat. I ended up using three NDI streams from the "camera", one video without audio and and two audio-only. The two audio channels I mixed to mono and panned each way in the advanced mixer.

However, while the audio sources where in perfect sync, the video lagged.

 

[AaronD]

However, while the audio sources where in perfect sync, the video lagged.

Sounds like you have a different problem.

Fiddle with the Properties for the video source, and then set them right. Often that cuts the latency down. (seems like a bug to me, but at least there's that workaround)

Then use the Sync Delay in the Advanced Audio Properties to delay the audio a little bit to make it all line up. The headphones (annoyingly) tap off before the Sync Delay, so you'll need to record some, play it back, tweak it, record some more, etc.
Or watch your own stream while being careful to not let it feed back, and remember that there's likely a 10-second delay or so through all of the "cloud" stuff. So don't "see that it's not doing much" and grossly overshoot.