vMix Setup Guide

vMix is almost always used as a destination in SRT Matrix — the 3-slot vMix-shaped destination this whole system was originally built around. vMix receives routed sources as SRT inputs, and its program-out (or any of its own outputs) can be sent back to the field as a return feed.

Menu wording can shift slightly between vMix versions — the settings and values below are what matters; if a label has moved, look for the nearest equivalent (vMix has supported native SRT input/output for several versions now).

Setting up vMix to receive routed slots

vMix never needs to know about SRT Matrix's routing — it just needs 3 SRT inputs sitting and listening, ready for SRT Matrix to dial into whichever one is currently routed.

In SRT Matrix, add a destination with type "vMix / OBS (SRT, 3 slots + program-out)", with Host set to this vMix machine's own LAN IP. Note the 3 slot ports shown on its card (e.g. 12011, 12012, 12013).
In vMix: Add Input → SRT (listed under the network/streaming input types).
For each of the 3 slots, add one SRT input:
- Mode: Listener (vMix waits for a connection — SRT Matrix is always the one calling in to a destination).
- Port: the matching slot port from step 1 (input 1 → first slot's port, input 2 → second, input 3 → third).
- Latency: vMix's default (typically 120ms) is fine to start — the gateway also defaults to 120ms on its side. If you need to raise it for a rough network path, you can either raise it here in vMix, or override it gateway-side via Edit ports on the destination's card (whichever's more convenient — SRT negotiates the higher of the two ends' latencies anyway).
- Leave passphrase/encryption off unless you've specifically set one on the SRT Matrix side — click Edit ports on the destination's card to check/set one. If a passphrase is set there, vMix needs the exact same one entered here or the connection is refused.
Repeat for all 3, so vMix has 3 inputs sitting in Listener mode on the 3 slot ports. They'll show as black/no signal until SRT Matrix actually routes something into that slot and dials in — that's expected, not an error. Once routed, a traffic stat should appear next to that slot's status dot in SRT Matrix — if it stays at 0 B even with a green dot, vMix isn't actually receiving data yet.

Setting up the return/program-out feed

This is how you send vMix's own output (or any input) back out to the field, through SRT Matrix, as a source's return/preview feed.

In vMix, decide what you want to send back — usually Program (vMix's live output), but it can be any input.
Add Output → SRT (this is a separate step from the 3 inputs above — vMix outputs and inputs are configured independently).
- Source: Program (or whichever output you're sending).
- Mode: Listener.
- Port: the destination's program-out port shown on its card — always 14000, fixed and shared across every SRT destination (not overridable from the dashboard).
Start that output in vMix. SRT Matrix's gateway will dial in and start pulling it automatically — nothing further to configure on the vMix side.
Back in SRT Matrix, route a source's return to this destination's program-out (drag the destination's header onto the source's return zone) to send this feed back to that specific field encoder.

Two vMix instances on one machine

If you're running two vMix instances (or vMix + OBS) on the same physical box, they can't both use the shared program-out port (14000) — it's fixed and not overridable from the dashboard. Today, the only ways around this are:

Run the second instance on a different host or VM (each destination is disambiguated by IP address, not port, so this is the simplest fix), or
Only rely on program-out from one of the two instances on that box, and skip return/program-out routing for the other.

Quick reference

What	vMix side	SRT Matrix side
Receiving a routed slot	Add Input → SRT, Mode: Listener, Port: slot port	Destination card shows the 3 slot ports; traffic stat shows next to each slot once routed
Sending a return/program-out	Add Output → SRT, Mode: Listener, Port: program-out port	Always `14000`, fixed — not overridable
Passphrase set on the destination	Enter the same passphrase in vMix's SRT input/output	Check via Edit ports on the destination's card