Program and preview, keying, mix/effects, streaming and recording — the vocabulary of live switching sounds like broadcast jargon until you see what each control is for. This is the ATEM feature set explained in plain language, drawn from Blackmagic Design’s documented capabilities.
A video switcher (or “vision mixer”) takes several video inputs and lets an operator choose, in real time, which one — or which combination — is sent to the audience. That single chosen output is the program. Everything else on the panel exists to control how you get to that program feed and how you move between sources cleanly.
An instant switch from one source to the next — the cleanest, most common transition. On an ATEM the CUT button takes preview to program with no effect.
A timed cross-fade between two sources. The AUTO button performs the transition over a set rate for a smooth, deliberate change.
One source is revealed over another along a moving shape or line. ATEM switchers include a library of wipe patterns.
The digital video effects engine can push, squeeze, or slide sources on and off screen for motion transitions and picture-in-picture moves.
Keying is how a switcher overlays one image on another — a lower-third title over the shot, or a presenter composited onto a virtual set. ATEM switchers provide upstream and downstream keyers, documented in Blackmagic’s manuals.
Removes a solid colour — the classic green screen — so the subject appears over another background. Even lighting on the screen is what makes a clean chroma key.
Keys based on brightness, used to lay graphics and titles with transparency over the program image.
Applied inside the mix/effects processing, these composite sources and graphics into the program before it leaves the M/E.
Sit at the very end of the chain, ideal for logos and lower-thirds that must stay on screen through cuts and transitions underneath them.
M/E stands for mix/effects — a complete processing block that combines sources, transitions, and keys into one output. Larger switchers have several M/Es; the compact ATEM Minis center on a single, capable M/E. SuperSource, available on the ATEM Mini Extreme and larger models, is a compositing engine that arranges multiple sources into one layout — the picture-in-picture boxes you see behind a news anchor, built as a single composed source.
Multiview is the operator’s dashboard: a single monitor output divided into panes showing every input plus the program and preview feeds at once, so you can see all your cameras and cue the next shot at a glance. The ATEM Mini Pro and Extreme output a multiview; it is one of the most valued upgrades over the base model.
Where the ATEM Mini line reshaped the market is by folding a streaming encoder and recorder into an affordable switcher. Here is how the models differ, per Blackmagic’s published feature set.
| Model | HDMI inputs | Streaming & recording |
|---|---|---|
| ATEM Mini | 4 | Outputs program over USB as a webcam source for a computer to stream; no built-in encoder. |
| ATEM Mini Pro | 4 | Built-in hardware H.264 encoder streams directly over Ethernet; records to a USB disk; multiview output. |
| ATEM Mini Pro ISO | 4 | Everything in the Pro, plus records each input as an isolated file and writes a DaVinci Resolve project for re-editing. |
| ATEM Mini Extreme / Extreme ISO | 8 | More inputs, more keyers, SuperSource, dual USB recording, and additional multiview and output options. |
All of these are controlled by hand on the unit or through the free ATEM Software Control application, which exposes the full palette — keyers, media pool, audio mixer, macros, and camera settings — on a computer. And because every one of these switchers is fanless, keeping it cool is part of keeping it reliable: see ATEM Mini cooling. Ready to build the rig around it? See the live production setup guide.
Program (PGM) is the feed that is live on air right now. Preview (PVW) is what you have queued up next. You build your next shot on preview and then take it to program with a cut or transition, so unfinished shots never reach the audience.
M/E stands for mix/effects — a processing block that combines sources, transitions, and keys into one output. Large switchers have several M/Es; the compact ATEM Mini switchers focus on a single capable M/E.
Upstream keyers composite sources and graphics into the program inside the mix/effects processing. Downstream keyers (DSK) sit at the very end of the chain and are ideal for logos and lower-thirds that must stay on screen through cuts happening underneath them.
Per Blackmagic’s specifications, the ATEM Mini Pro, Pro ISO, and Extreme models include a built-in hardware encoder that streams directly over Ethernet. The base ATEM Mini outputs its program over USB as a webcam source for a computer to encode and stream.
It is Blackmagic’s free companion application that exposes the switcher’s full feature palette on a computer — keyers, the media pool, the audio mixer, macros, and camera settings — beyond the buttons on the physical unit.