Couldn’t you do this a lot easier by just using running OBS on the second machine and use the capture card for whatever your input is?
But I suppose you could full screen OBS on the first machine and then use the input card on the second to grab the preview. The second machine would essentially be an extra monitor thru your capture card.
I'm trying to have multiple OBS audio tracks get sent through the capture card as well.
The main reason is I'm playing PCVR and trying to offload the main encoding work to a streaming PC -
1. Without having to send audio from each PC to the other and route it correctly
2. Be able to control things in OBS and other streaming programs without having to take my headset off
NDI works alright, but it was lagging pretty bad last time I used it for some reason.