NDI Sources

NDI (Network Device Interface) is a widely used standard for sending video over a local network. pMix.studio can receive NDI sources from cameras, software (OBS, vMix, Wirecast), and hardware devices.

Adding an NDI source

Tap + on an empty source slot
Select NDI
pMix.studio discovers NDI sources on your network automatically via mDNS (Bonjour)
Select the desired NDI source from the list

The source connects and begins displaying in the slot. NDI sources include both video and audio.

Discovery

NDI discovery uses mDNS multicast. For sources to appear:

All devices must be on the same local network (same subnet)
Your router/switch must allow multicast traffic (most consumer routers do by default)
Some managed switches may need mDNS/multicast forwarding enabled

If a source doesn’t appear, try refreshing the source list. You can also check that the NDI source is visible from other NDI receivers on the same network.

An NDI source whose sender was offline when you loaded the project keeps its name and shows as waiting, rather than looking like an empty slot. It reconnects on its own when the sender comes back.

Bandwidth

Each NDI source has a bandwidth setting in its properties:

Setting	Behaviour
Force HIGH (default)	Always request the full-quality stream
Automatic	Let NDI drop to the low-bandwidth proxy stream when the source isn’t being shown large

Force HIGH is the default because a source that quietly proxies down looks soft the moment you cut to it. Switch a source to Automatic when it’s only ever a thumbnail — a confidence feed you never take to program — and you want the network back.

PTZ control

If your NDI source supports PTZ (pan-tilt-zoom), pMix.studio can control it via NDI PTZ commands:

Pan and tilt — Directional control
Zoom — Zoom in and out
Presets — Recall saved camera positions
Image — IRIS, GAIN, SHUTTER, RED and BLUE

PTZ controls appear automatically when you select an NDI source that advertises PTZ capability. Cameras that don’t support PTZ simply won’t show the controls.

Commands can go over NDI PTZ or direct to the camera over VISCA over IP — chosen per source in Edit Properties. See NDI PTZ Control for setting VISCA up, what the NO VISCA warning means, and how the image controls report what a camera actually confirmed.

Audio

NDI sources carry audio alongside video. The audio appears in the mixer automatically at the same slot number as the video source. You can adjust volume, mute, and routing independently.

Lip sync

An NDI camera’s sound normally reaches pMix.studio ahead of its own picture — around 100 ms on the bench, and 133–200 ms reported on a BirdDog X4 — because the NDI receiver queues audio before the app can see it. Settings → Diagnostics → NDI Camera Lip Sync chooses how much of that pMix.studio corrects:

Mode	What it does
Full Correction (default)	Holds the audio with its picture, releases it at the right moment, and cancels the receiver’s own queue delay. On the bench this brings 100 ms of error down to about 11 ms; in the field it is in sync to the frame on a BirdDog X4
Hold Only	Holds the audio with its picture whenever the mixer is delaying that camera, but does not cancel the queue delay
Off	The older playout behaviour, with no correction

Full Correction holds each NDI camera’s picture a little longer to make room, so cuts and PTZ moves on NDI cameras feel slightly further behind. The setting affects NDI cameras only — iPhone cameras, SRT, media files and the iPad’s microphone are untouched.

If audio from an NDI camera starts sounding early, or you hear dropouts, step down to Hold Only or Off. This is the first setting to try. The change applies to cameras added after you change it, so re-add the camera or restart pMix.studio.

Common NDI software sources

Any NDI-compatible software on your network can be received:

OBS Studio — Enable NDI output plugin
vMix — Built-in NDI output
Wirecast — NDI output support
NDI Studio Monitor — For testing
Skype / Zoom — Some video call apps can output NDI

Performance tips

NDI uses significant network bandwidth (typically 100–150 Mbps per 1080p60 source)
Use a wired Ethernet connection for NDI sources when possible (via USB-C Ethernet adapter on iPad)
If using Wi-Fi, ensure your network has enough throughput for all simultaneous NDI streams
NDI HX (compressed NDI) sources work well over Wi-Fi at lower bandwidth