The OnAirCut manual

What OnAirCut is

OnAirCut is two apps in one, for Mac. The Live Switcher changes your ATEM’s cameras to whoever is talking, reading each microphone on its own from a multichannel USB console. The Podcast Editor builds the multicam edit of a recording for Final Cut Pro, Premiere Pro or DaVinci Resolve, without cutting by hand.

What you need

• A Mac with Apple silicon (M1 or later) and macOS 14 Sonoma or later.
• For the Live Switcher: an ATEM — any of the family — connected by USB or Ethernet, and a USB console that sends one person per channel to the Mac (a Mixcast 4, for example). A console that only sends the stereo mix isn’t enough.
• For the Podcast Editor: one audio file per person (or a multitrack file with one person per channel) and each camera’s video. It doesn’t need the ATEM or the console.

What stays on your Mac

• The console’s audio is analysed on your Mac, as it happens, to know who is talking. It’s only written to your disk when you record — with ▶ while Always REC is on (it comes on by default), or with ● REC if you turn it off — and it never leaves the Mac, nor is it used to train anything.
• The ATEM is controlled over your local network or USB, never through the internet.
• Your sessions, recordings, videos and edits stay on your Mac. The editor reads them from your disk and writes its exports next to them.
• The app goes online only to check the licence and to look for updates (on from the factory; it can be turned off in Settings). Fault reports are sent only if you ask. The details are in the privacy notice.

Opening it

The first time, macOS asks for permissions. Allow them: the microphone, to read the console, and the local network, to find the ATEM over Ethernet. The camera is asked for only if you turn on the ATEM preview.

• Live Switcher (key 1) switches the ATEM’s cameras by who is talking. It connects to the ATEM and the console. Only one copy can run live: two apps sending cuts to one ATEM would fight.
• Podcast Editor (key 2) builds the multicam edit of a recording. It doesn’t use the ATEM or the console, so it opens even while another copy is on air. Closing it brings you back here.
• At the foot: Manual (this manual, in your browser), About (the trademarks and every third-party licence) and Licence.

⌘, opens Settings from here too. Without the live window open, it shows only the licence and the language:

Connecting the ATEM and the console

Open the Live Switcher with the ATEM and the console plugged in. OnAirCut finds them on its own and shows them at the right of the top bar:

• The ATEM: its model and whether it’s on USB or the network. It looks on USB first and then on the network, and reconnects by itself if the cable or the network drops. If your ATEM is on another network, Devices → Use a fixed IP….
• The console: click it to choose another input. If it’s unplugged or plugged in after opening the app, OnAirCut picks it up again on its own.
• Any ATEM model works: Mini, Mini Pro, Mini Extreme, SDI, SDI Extreme ISO, Television Studio… On connecting, the app sees how many inputs it has and adds them under Cameras, unticked: tick the ones with a camera.

The live window

The top bar

• The pages: Live, Mics and Cameras.
• At the right: the ATEM, the console, Analyze (the magnifier over a waveform, which opens the assistant), the gear for Settings (⌘,) and AUTO, which turns the automatic switching on or off.

The strip, on every page

• On air and for how long.
• Last cut, with its reason and how long ago — it doesn’t change every second, so you can read it.
• Speed and the session, like a recorder: ▶ starts it, ■ stops it and ● REC records. ■ only works with the session running. With Always REC (Settings → General, on by default), every ▶ records too and the recording goes with the session: ● REC doesn’t stop it, only ■, which asks first. If you turn it off, ● REC pressed before ▶ stays armed and records as soon as the session starts; pressing it again disarms it.
• The clock starts at zero when recording starts (the tests before don’t count) or when you decide (⌘T), right away or with a countdown first — in amber, with a “−” and “STARTS IN” above it, in step with the guests’ clock. With a countdown, recording starts at zero: meanwhile ● REC shows armed, and pressing it records at once. The clock turns red while recording and stays at the final time when it stops. Click it to open the recording clock in its own window.
• Under it, how much recording fits on the disk (“Disk: 9 h”), in amber when it’s less than an hour, and how many markers the recording has.
• Notices (the pause after a manual cut, AUTO off) appear once, discreetly, at the bottom. If something needs setting, the notice brings its Fix… button.

Live

• Mics: the meter bridge, one meter per mic, with a white light on whoever has the floor. With more than 6 mics the meters get narrower so you see them all (up to 12; with more, the bridge scrolls sideways).
• Cameras: one monitor per input, like the ATEM’s multiview. Red border = on air, green = what’s coming. Below each one, the meters of the people it shows. A click cuts to it. With more cameras the monitors get smaller and simpler; if they no longer fit, the program gives way a little, so none overlaps.
• The program: the ATEM’s output, live, when the ATEM preview is on (see Settings → General). It comes over the ATEM’s USB-C cable: over Ethernet alone there’s no picture.
• Last 60 seconds: who spoke and which camera was on air. It explains every cut. When you stop (■) it stays as it was, until the next ▶. With many people the rows get thinner so everyone fits.
• The cut log: the automatic cuts, yours and the ATEM’s. Above it, Saved sessions… and Podcast Editor… (with the session stopped).

Mics

• The meter bridge, in dB. The white LED says who is talking.
• The triangle is each mic’s threshold: grey = automatic, amber = set by hand.
• A click or a drag on the meter sets it by hand; a double-click returns it to automatic. A click on the name changes nothing.

Cameras

• Each input with a camera, who it shows, how long it’s been on air, what % of the time and how many cuts. The counters start from zero when you record a session, or from Session → Reset camera counters.
• Minimum: how long that shot lasts at least. Auto uses the one in Settings.
• Maximum: if someone stays on the same camera for a long time, the app puts up a variety shot for about 4 seconds and comes back. From a single shot it goes to the tightest camera with more people (a shared one or the wide); from a group shot, to whoever is talking. Recommended: 60 s on single cameras.

The ATEM preview

The big monitor at the right, the program, can show the output the ATEM sends over USB-C as a webcam: press Show ATEM signal (or turn it on in Settings → General, or View). It’s off by default; the first time, macOS asks for camera permission. macOS lets several apps use that camera at once, so OBS keeps working the same.

The assistant: Analyze, once per profile

Press Analyze in the top bar (or Devices → Analyze (assistant)…). In a few minutes it learns which mic belongs to whom, which camera shows whom, the room’s noise and each voice. You do it once per profile; when the studio changes, run it again. Opened from ▶, it can be skipped with Skip and start.

Step 1 · Mics

Turn on, in the row of keys, only this session’s channels. Talking into a mic lights a white bar under its number, so you can tell which is which. Two neighboring keys marked MIX always sound exactly alike: that’s the console’s stereo mix, so leave them off. OnAirCut doesn’t guess the other channels: you know which mic is whose.

Step 2 · Cameras

• Mark the inputs that have a camera and give them a name.
• Tick who appears on each one. One person: their single shot. Several: a shared camera (used when any of them talks). Everyone: the wide shot. Nobody: the input is used only by hand.

Step 3 · Silence

Four seconds with nobody talking: it measures each mic’s background noise (air conditioning, hum), so noise never counts as a voice.

Step 4 · One by one

Each person talks alone for about 10 seconds (from 6 seconds you can carry on). The app confirms their channel, measures their normal level and learns how much of their voice leaks into the other mics — the bleed. Then the next person:

Step 5 · At once

• About 8 seconds talking at once — first the people of each shared camera and, at the end, everyone, like an argument.
• In the photo, four people and only the wide shot to share: a single test (1 of 1), with a card per mic — one per person. With more mics, the cards get smaller so they all fit.
• Each person has a card with their waveform and a voice light. At the right you see live which camera the app would put up, with a green frame when it’s the right one.
• If the bleed protection hides someone who talks softly, the app loosens it just enough, without letting in the bleed it measured with each person alone. If even so someone stays hidden, it says so: move their mic closer or the mics apart.

Step 6 · Summary

The bleed table, the result of the tests at once and any warning. Save and activate: AUTO switches on.

How it decides

• One person talks: the tightest camera they appear on.
• Several talk at once, sustained (1.5 s by default): the tightest camera that shows all of them. The wide shot when at least the number you set talk, or everyone.
• A short “uh-huh” or a brief comment doesn’t take the shot from whoever has the floor.
• If someone off camera clearly carries the conversation for a while, it goes to them.
• Silence: stay, go to the wide shot or go to a camera you choose.
• It respects the operator: after a manual cut — in the app, with the keys or on the ATEM — it waits a few seconds. It never cuts over a logo, black or the media player you put on air from the ATEM; Resume auto ends that pause.

The four speeds

Speed sets four times at once. If you change one by hand, it becomes Custom.

It learns during the show

• Each person’s level: if someone starts shy and then opens up, or lowers their voice on a delicate subject, the app follows their normal level. Everyone is compared with their own voice, so a loud guest doesn’t take the shot from a quiet one just by talking louder.
• Bleed: if someone moves their mic closer or further, the bleed is learned again — only when one person is clearly talking alone.
• Closer or further: if someone leans back from their mic or comes closer during the show, the app notices and keeps them on camera, instead of going to the wide shot as if everyone were talking. When two people really talk at once, it still opens the shot.
• Constant noise (air conditioning, hum) isn’t mistaken for a voice.
• What it learns is saved every 2 minutes and on closing. It can be turned off: Settings → Voice detection → Learn during the show.

Settings

⌘, or the gear opens Settings. Every setting is a row with its name, a short line and its ?, which explains it when you hover. The window doesn’t block: the live view keeps running while you adjust. On the left go the rules of the active profile, the ones that decide the cuts; on the right, what applies to every profile: General, the Recording clock and its look.

At the bottom, Leave a review takes you to the review form on this site, and Done closes the window.

Licence

While everything is in order it’s a single row: the plan, the days left in the trial or the renewal date, and Details. It opens in full only when there’s something to do. See Your licence.

Cuts

Voice detection

Under them, Bleed learned for N of M mics says how many mics already have their bleed measured (the assistant measures it).

Several people at once

When nobody talks

Manual control

Transition

General, for every profile

Recording clock, for every profile

Clock look, for every profile

Profiles and menus

A profile keeps a studio’s whole setup: its mics, its cameras and who appears on each, the rules in Settings and what the app learned about each voice. Use one per set or per show — Profile menu: switch, New profile…, Duplicate profile, Rename profile… and Delete profile….

Recording the session

For when each camera records its own file — on its card, an external recorder or an ATEM ISO — and you’ll build the edit afterwards. ● REC doesn’t record video: video is recorded on the cameras or on the ATEM; start them yourself at the same time.

1. 1Start recording on every camera.
2. 2Press ▶: with Always REC (Settings → General, on by default) it records too — with a countdown, from the moment it reaches zero. If you turned it off, press ● REC (top right, or ⌘R) — before ▶ (it records as soon as the session starts) or during the session. If the disk has room for less than an hour of recording, it asks first (Record anyway / Don’t record; with ▶, Don’t record starts the session without recording). Without the console, or with no mics in the profile, it records only the cuts and says why (OAC-E5). The app saves, in the session’s folder: every cut with its exact time (automatic, by hand or from the ATEM), a 24-bit WAV per mic in exact sync with the cuts, and who appears on each camera, so the editor has it even if you change the profile later.
3. 3While recording, press M whenever something happens — a good moment for social media, something to cut. Each marker shows on the timeline of the Podcast Editor and goes into the export: markers in Final Cut and DaVinci, sequence markers in Premiere.
4. 4At the end, press ■ or ● REC again. While recording, ■ asks first: OK stops the session and the recording; Cancel (the default, in case you pressed it by accident) keeps recording. ● REC stops recording and the session stays live. Then stop the cameras.

• Sessions go to Documents → OnAirCut → Sessions, a new folder per session (“date time profile”): never written over another. It can be changed in Session → Sessions folder….
• The small clock difference between the console and the Mac is corrected, and if the console drops for a moment the gap is left silent, so the track stays aligned.
• They save themselves every 5 seconds, with everything the editor needs: if the app closes suddenly (a power cut, a hang), the session is whole up to that moment. The editor opens it and says it wasn’t finished.
• If the disk fills up or is disconnected while recording, the app says so at once, and why. With less than 10 minutes of recording left on the disk, it warns you first, at the bottom.
• Closing the app while recording, it asks first.

The recording clock

The recorded time, big, in its own window — for your guests or the studio’s client. Drag it to another screen or a TV; double-click it to fill the screen (Esc brings it back). With Always on top (in Settings or with a right-click), no other window covers it. It opens with a click on the live clock, from View → Recording clock (separate window) or in Settings → Recording clock → Clock window: Open. If it was open when you closed the app, it opens again by itself, on the same screen.

• When does it start? Automatically (the default), with the recording — when you press ▶, since Always REC comes on, or ● REC if you turn it off; the sound check before doesn’t count — and it stops when recording stops; or when you decide, with Session → Start the clock (⌘T) or a right-click on the clock — while it waits, “⌘T TO START” shows next to REC, and ⌘T also works with the clock window in front. ■ always stops it, and stopped it stays at the final time (STANDBY, dimmer).
• How does it start counting? Right away (the default), from 00:00:00; or with a countdown, so your guests get ready: “STARTS IN” counts down the minutes you choose, at zero a message shows for a few seconds (“ON AIR!”, or yours) and the clock counts from zero. Recording starts at zero, so the wait before the show isn’t recorded, while the live show goes on as usual; meanwhile ● REC shows armed and, if someone starts early, pressing it records from that moment. To record the countdown too, turn on Record during the countdown in Settings → Recording clock.
• Whoever is operating sees it too, even without the TV: the app’s clock, next to ● REC, shows the same countdown in amber with a “−” and “STARTS IN” above it, and at zero “ON AIR!”, with a notice at the bottom and a line in the log. Nothing is drawn over the ATEM’s picture.
• While recording, “● REC” and a frame in the recording color light up, like the tally of the camera on air. With a countdown, they light up at zero, together with the message.
• HH:MM:SS or timecode (00:42:17:12), with its frame rate; at 29.97 and 59.94 in drop frame, so it doesn’t fall behind the real clock. The countdown and its message go in hours, minutes and seconds: the frames show once it counts.
• The time of day (off by default): the Mac’s, at the bottom right, in 12 or 24 hours, with or without seconds. Useful when the studio is rented by the hour: the client sees what time it is and how long they’ve been recording.
• Your logo and your colors, in Settings → Clock look. Reset goes back to the defaults: black, white digits and red when recording.
• Right-click: start, stop or reset the clock, full screen, timecode, the time of day, the frame, Always on top and More options… (Settings).

Saved sessions

• Saved sessions… — next to Podcast Editor… in the live window, in Settings → General or in Session → Saved Sessions… — lists the recorded sessions: how long each lasts, its cuts, its tracks and how much space it takes.
• A double-click opens it in the editor; you can also show it in the Finder.
• Move to Trash… (⌘⌫) sends it to the macOS Trash after asking: you can recover it from there, and the space is freed when you empty it. Nothing is ever deleted outright.
• Only the app’s session folders are moved, never the one being recorded. A damaged session also appears, so you can delete it; one that wasn’t finished saving says Unfinished.

The Podcast Editor

It builds the edit for Final Cut, Premiere or DaVinci in four steps — Audio, Video, Cuts and Export. At the top you see which one you’re on, and you can always go back. Open it from the start screen or Session → Podcast Editor… (⌘E). It’s used with the session stopped: while the live session runs (▶ or recording) it doesn’t open.

Where the material comes from

• An OnAirCut session: its tracks are the sync reference. If you also recorded on the console (its card, a recorder, a DAW), choose each person’s audio: it lines itself up against OnAirCut’s track and is the one that stays in the edit.
• Files (without having used the app live): one audio file per person, or a multitrack file (WAV, AIFF or CAF) with one person per channel. The tracks must last the same (the app checks).

The cuts: from the live show, or from the whole recording

• From the live show: exactly the cuts OnAirCut made. The edit is the same as what went out.
• From the whole recording: calculated again, knowing the whole conversation. It separates each voice from the bleed by comparing the waveforms between mics, not just the level; it sees each turn whole (short pauses don’t split it and a quick “uh-huh” doesn’t change the shot); it picks the best sequence of shots respecting the minimum per shot, and every cut lands right where someone starts talking, without the live delay.

Progress: while it reads, syncs, calculates or exports, the bottom shows the step (“Step 2 of 4 · …”), the percentage, the time and how much is left. Stop stops it; closing the window too.

Step 1 · Audio

• Audio files (where it starts): drag each person’s audio, or Choose files…. A multitrack file is split into one person per channel. OnAirCut session: choose a recorded session.
• Each person gets a card with the waveform of the whole recording: white where they talk, grey where they don’t (noise, or someone else’s voice leaking in). Rename them with a click on the name.
• Master track (optional): your final mix, from Auphonic for example. If it lasts the same as the tracks, it starts with them and the sound only confirms it (and measures the milliseconds the processing adds); if not, it’s synced by sound. It goes on top in the edit, with each person’s tracks silent underneath.
• If a file can’t be read (damaged, incomplete or in a format macOS doesn’t know), the app says so and doesn’t add it (OAC-A6).

Step 2 · Video

• Drag each camera’s video (you see its thumbnail), name it and tick who appears on it. They sync on their own.
• The app reads each file’s resolution, frame rate and timecode. Settings… on each camera fixes them if the camera had them wrong:

How it syncs

• By timecode, if the file has it and it agrees with the sound. If the cameras share timecode with each other but not with the Mac’s clock, their timecode is used and the sound only places them.
• If there’s no timecode or it doesn’t agree, by sound: it compares the camera’s audio with the mics’ tracks, to a fraction of a millisecond.
• It also measures each camera’s clock drift (30 ppm, for example, is 0.1 s in an hour) and corrects it on every cut.
• It checks at many points of the recording. If they don’t agree (the video is from another day, say), the card says Unconfirmed sync and the export warns about it. If a camera can’t be heard, its card says why: no sound in the video, a damaged file or a disconnected disk.

Timecode at any frame rate

• 23.976, 24, 25, 29.97, 30, 50, 59.94 and 60. It’s read the way the camera counts it — one at 59.94p usually counts at 30 — and exported the same way.
• Drop frame (only at 29.97 and 59.94; cameras show it with “;”): the file’s is respected, and you can tick or untick it in Settings…. If you type by hand a label that drop frame skips (00:01:00;00, for example), the app tells you before accepting it.
• Between cameras, timecode is compared in real seconds: it lines up even if they started recording minutes apart.

Step 3 · Cuts

• The cuts calculate themselves. A bar shows each camera’s % and shots, so you can review them before exporting. With many people the lanes get thinner and the camera legend shorter, so everything fits.
• Speed, several at once and Max on the same person are adjusted here, and the cuts recalculate in under a second, without pressing anything. The same happens if you change who appears on a camera.
• Max on the same person places the variety shot in a natural pause.
• The markers you added with M while recording show on the ruler, numbered in amber, and go into the export.
• ▶ (or the space bar) plays the edit in the viewer, with the master track if you added it — to review only: the editing happens in your video editor. While cameras sync or cuts calculate, the viewer says so and ▶ waits.

Step 4 · Export

• Choose the editor — Final Cut Pro, Premiere Pro, DaVinci Resolve or Cut list — and, below, the clip type and how the cameras arrive. At the right, the summary of what will be exported.
• Clip type (Final Cut and DaVinci): Multicam (the default in Final Cut) — one angle per camera plus one of mics, so you change the angle of any cut with one click — or Separate clips. Premiere always goes as separate clips: it doesn’t import multicam by XML.
• With separate clips, Each camera on its own track (the default), with the unused footage disabled (each track has its camera’s whole recording, switched on only where it’s used) or cut out (each track has only its used parts); or Merge into one track (only the chosen shots, in order — the unused takes are lost).
• Frames per second of the timeline: the cameras’, or the one you choose. It warns if a camera doesn’t match.
• Markers (the ones added with M while recording) go in every format: inside the multicam clips or gaps of Final Cut and DaVinci, and as sequence markers in Premiere.
• The edit’s audio is each person’s tracks; the cameras’ audio stays off. With a master track, the master goes on top and each person’s tracks stay silent underneath.
• Timecode: in the EDL, the cut list and Premiere’s XML, each camera keeps its own timecode (its frame rate and its drop frame). The timeline goes in drop frame if the cameras count that way.
• Every export goes to a new folder (“Export date time”), with the instruction to open it in that editor: nothing is ever written over another. You can choose another editor and export again.
• The same material carries the same identifier in every export: importing another version into the same Final Cut library doesn’t duplicate the clips.

Your licence

The licence lives at the top of Settings. While it’s in order it’s one row; Details shows who it’s registered to, the Macs using it and the subscription:

• Activate: paste the key from your purchase email and press Activate. The field cleans what sneaks in when pasting (spaces, line breaks, odd dashes, invisible characters, quotes). It works on 2 Macs at once.
• Release: frees this Mac’s seat to use the licence on another one. A licence can change Mac 10 times every 30 days; each change comes back 30 days after it was used. Reinstalling on a Mac that still has its seat isn’t a change.
• The Macs: each with its name and activation date; your own says This Mac. If the list doesn’t load, you can release a seat from the Mac that has it, or write to support@soonus.net.
• Manage subscription: a link to your account arrives by email, where you cancel, change the card or download invoices.
• Offline: it keeps working 14 days since the last time it confirmed the licence. Confirming never stops the live switching.
• Free trials: 7 days each, and each Mac can use two.

When there’s something to do

The start screen only talks about the licence when there’s something to do — it expired, it’s on hold, it’s missing — with a light in the colour of the state, the notice and the button that fixes it. Licence at the foot of the start screen (or Help → Licence…) opens its window:

If a VPN, a firewall or a network filter blocks the check, the app keeps working with the last check and says which domain to allow — onaircut.com, with a Copy button — and Try again. If someone else runs your network, ask them to allow it with its subdomains, over HTTPS. To activate or release a Mac, the app also talks to live.dodopayments.com (Dodo Payments’ licence service): allow it too.

Licence messages

Each message says whose problem it is and carries an OAC-L code for support. Red: the problem is the licence. Grey: it isn’t a fault — there’s something to do.

When something fails

Every error says what failed, why, what to do and whose side it’s on:

• “You can fix this on your side”: a file, the disk, a macOS permission or a device. The notice says exactly what to check.
• “OnAirCut fault”: an error in the program. Press Copy details (the version, macOS, the error and where it happened) and send it to support — or through the contact form.
• The error window never blocks: the live switching keeps cutting. Everything also goes to the log (Help → Open app log).

Keyboard shortcuts

The live shortcuts can be turned off in Settings → General or Control → Keyboard shortcuts.

Built to run during a show

• No App Nap: the app doesn’t slow down even behind OBS, and the Mac doesn’t sleep while it’s open.
• It reconnects: it finds the ATEM by itself, first on USB and then on the network, and reconnects if it’s lost. If the console drops or is plugged in after opening the app, it picks it up again.
• It asks first: before closing while recording or with AUTO on, and before removing mics.
• Settings are backed up on every save; if the file is damaged, it’s set aside and the backup is restored.
• The network never slows the show: the licence check runs on its own thread.
• A log of errors: Help → Open app log.

Full specifications

Cameras and switcher

Microphones and voice

How it switches

Recording the session

Podcast Editor

Export

Mac and licence

Glossary