NDI is not free just because it stays on your LAN
It finds the other machine on its own and just works. Then you add a third source and the whole thing falls over, on a gigabit network you were told was plenty.
NDI sends video over your network. No capture card, no cable to run, discovery handled for you.
The setup is so easy that people skip the part where they work out what it costs.
What one stream needs
Full NDI uses light compression on purpose. It keeps quality high and latency low. It pays for both with bandwidth.
Budget roughly 100 to 160 Mbps for one 1080p60 stream. A gigabit link carries a handful. After that, everything else on the network gets squeezed.
Two cameras and a screen share is half your gigabit. That is before the return feed to a monitor.
NDI HX compresses hard and needs a fraction of the bandwidth. It costs latency and some quality. For a camera feed into a scene, take the trade.
What breaks first
- WiFi. Full NDI over WiFi does not work in any dependable way. Use HX, or use a cable.
- Cheap switches. An unmanaged switch with a small backplane will not carry several NDI streams at once, whatever the port label says.
- The uplink between switches. Two switches joined by one gigabit link. Every stream crossing it shares that one cable.
- Discovery across subnets. NDI finds sources by multicast. Put machines on different subnets and they stop seeing each other until you run a discovery server.
Building it so it holds
| Setup | What it supports |
|---|---|
| Gigabit, unmanaged switch | Two or three full NDI streams. More on HX. |
| Gigabit, managed switch | Same bandwidth, but you can see where it goes and control multicast. |
| 2.5 gigabit or 10 gigabit | Full NDI at production scale. The right answer for a fixed studio. |
| Dedicated video network | Video traffic never competes with anything else. What broadcast does. |
The cheap discipline
Put the video machines on their own switch. Give each one a cable. Keep internet traffic on a different path where you can.
Then test at full load before you need it. NDI answers contention by dropping frames. It does that during the show, not during setup.
Sources
The Rig Wire reports on streaming technology from public documentation, source repositories and vendor releases. We did not bench-test what is described here. When we have tested something, we say so.