The fact that you cite 25 Mbps per source points to NDI-HX. You must be using PTZ cameras or Newtek Sparks.

NDI auto aggregates bandwidth across connections. If you add a second (or 3rd) network connection to your vMix host you will increase the available bandwidth proportionally, even with no change to vMix itself.

Check NDI Router from Zen Computer. It allows to switch and route NDI sources on the fly in order to avoid the need of "loading" these 50 sources all together as I believe you don't need them all at once

Guillaume

Network is not the main/only issue. Don't forget CPU power needed for 50 NDI streams on a single host


I totally agree, but I don't think it's possible to "monitor" (I mean monitor not just barely see if sthg's moving) with vMix's input bar. Thus multiview is required. For 50 inputs, that's at least 3 monitors with 16 inputs each. That's a lot and imho risky. For critical operations, I'd go for a multi computer setup only for monitoring, +1 for routing to the production unit. This does not solve the bandwidth issue (it simply multiplies it) but at least, if one computer crashes, you don't lose everything.
When you're about to design a solution for 50 NDI inputs, you must have the appropriate budget to make it work in terms of networking and hardware. Expecting to use a single vMix for this is just a joke or insanity...

Guillaume