Talkback / IFB for live production inside a Zoom meeting.
ZComms gives a director or producer a desktop comms panel for cueing talent through Zoom's talkback channels. Talk to one person, build a group line, or use ALL CALL. Panelists listen through their ordinary native Zoom client; they do not need ZComms, virtual audio cables, or an additional account.
Download for Windows · Release history · Report an issue
| Platform | Status |
|---|---|
| Windows x64 | Desktop app available. Latest published release: v0.1.14, September 2, 2026. |
| macOS | In development. The audio core, shared talkback logic, and macOS SDK adapter have build/test coverage; the desktop app and live-meeting integration are not yet available. |
The Windows release includes a per-user installer and a portable ZIP. The
installer places the app in %LOCALAPPDATA%\ZComms\app without requiring
administrator rights and includes the Zoom Meeting SDK runtime. Builds are
currently unsigned, so Windows SmartScreen may prompt on first launch.
- Person-based talk keys. Eligible participants are assigned to individual talkback channels as capacity allows, with their names on the panel.
- Direct, group, and all-call comms. Hold a person's key, latch a channel, or key the whole bank. EDIT TALENT lets you change channel membership and create shared lines. Zoom supports up to 16 channels with 10 listeners each.
- Extern audio feeds. Route a single input channel or a stereo pair from a multichannel capture device to a talkback channel. Stereo pairs are downmixed to mono. Each feed has its own gain, latch, and input meter.
- Signal-driven ducking. Active talkback audio reduces the channel listeners' meeting-audio level. Operator speech also ducks an extern feed beneath the voice; a silent latched feed does not trigger ducking.
- Breakout-room awareness. The panel shows participant room information and unavailable destinations. The station-room selector lets the operator move between rooms when Zoom permissions allow.
- Microphone controls. Input gain, look-ahead limiting, ramped talk transitions, sidetone monitoring, device selection, and a test tone through the microphone processing chain.
- In-app meeting controls. Sign in, paste a meeting link or ID, enter a passcode when requested, and leave a meeting without closing the app.
- Operational feedback. Connection and transmit lamps, input meters, channel membership, send counters, and an expandable event history.
Use a headset for monitoring. Talkback is designed for production cues: repository measurements of the Zoom talkback path recorded approximately 165 ms median / 194 ms p95 one-way latency in one test setup; actual latency depends on the devices, network, and meeting.
- Install and open ZComms on Windows. Connect a microphone and headset.
- Select SIGN IN to authorize Zoom in your browser. Normal app use joins
meetings as your signed-in Zoom account. Stored tokens are encrypted with
Windows DPAPI under
%APPDATA%\ZComms. - Paste a Zoom meeting link or meeting ID and select CONNECT. Enter a passcode or wait for admission if the meeting requires it.
- Have the host make ZComms host or co-host so it can create talkback channels. The app retries channel setup while you arrange the role. When it is host, it also admits participants from the waiting room.
- Open SETTINGS to choose microphone and sidetone output. Check the destination assignments in EDIT TALENT, then hold a person's key to talk.
Panelists need a native Zoom desktop or mobile client that supports receiving talkback. The Zoom web client cannot receive it. Talkback also stays within the station's current room; it does not cross breakout rooms.
On a listener's machine, talkback may use the operating system's default communications output rather than the speaker selected in Zoom. Check that output when preparing a multichannel interface for a show.
| Control | Action |
|---|---|
| Hold a person or group cell | Momentary talk to that channel. |
| Digits 1–9 | Key the first nine displayed destinations while the panel has focus. |
| SPACE or ALL CALL | Momentary talk across the channel bank. |
| LATCH | Change cell/all-call presses to toggle transmission on and off. |
| EDIT TALENT | Add or remove participants using the numbered channel chips. |
| SETTINGS | Select devices, adjust processing, configure feeds, or move the station between rooms. |
| LEAVE | Leave the current meeting and return to the connection panel. |
Key colours reflect channel activity and known membership/reach information; they are not a measurement of sound at a panelist's headphones. The LINK, MTG MIC, CHANNEL, and TX lamps show the station's meeting and transmit state. Click the status strip to expand its event history.
In SETTINGS, choose a SOURCE, its input CHANNEL, and the destination under HEARD BY. You can use a console bus, a Dante interface, or another capture device exposed to Windows. Each destination slot can carry one feed; its controls let you latch, adjust gain, or remove it.
Input meters remain active while the feed is unlatched. They cover
−60…0 dBFS over 12 segments, with the −50 dBFS activity threshold marked.
Below that threshold the system treats the feed as inactive for ducking and
status; this does not mean the audio has been muted. A latched feed can show
latched · silent while low-level input is still present.
Feed device selections, channel picks, gain, and latch state are saved in
%APPDATA%\ZComms\feeds.env and restored at launch. HEARD BY describes the
current occupants of the destination channel; check those assignments when
changing meetings or reconfiguring a rig.
ZComms is early software. The core talkback path, channel isolation, and breakout-room awareness have been exercised in live meetings. Extern-feed end-to-end delivery and extended operation, breakout creation/assignment, and desk-to-desk chat signaling still have live validation work ahead. Rehearse the intended setup before using it on a production.
Development on main since v0.1.14 adds Windows and macOS CI, a shared
TalkbackSdk interface, tests for the channel layer, and the macOS talkback
adapter. These are source-tree developments, not a new packaged release.
The local command API also includes breakout administration and chat cue / assignment-notice commands. These are developer/integration surfaces; they are not all exposed as controls in the desktop panel. A ready-made Stream Deck or Companion module is not included.
See release history for version-specific changes and the macOS port plan for platform work. Planned work includes the macOS desktop app, named party-line channels, a dedicated ZComms Zoom Marketplace identity, code signing, and further live qualification.
Every run writes a log to %APPDATA%\ZComms\logs, including launches from a
console. Logs can be read while the app is running, rotate by size, and keep
the last ten runs. The application also records heartbeat and stall
information for troubleshooting.
When reporting an issue, include the app version, what you were doing, your audio devices, and the relevant log. Review logs for meeting or participant information before posting them publicly.
Windows x64, a Visual Studio C++ toolchain (Visual Studio 2022 or newer), and CMake 3.20 or newer are required.
Supply the Windows Zoom Meeting SDK 7.1.5+ under
third_party/zoom-sdk, with lib/sdk.lib, h/, and bin/ in that directory.
The SDK is not included in the source repository. The WebView2 SDK is fetched
at configure time.
cmake -S . -B build -A x64
cmake --build build --config Release
ctest --test-dir build -C Release --output-on-failureWith the Zoom SDK present, the build includes the zcomms desktop app.
Without it, the audio engine, SDK-independent tests, and diagnostic tools
still build. tools/release.ps1 stages the Windows ZIP and NSIS installer.
The current macOS target is the engine and talkback adapter, not an installable desktop app. With Xcode command-line tools and CMake installed:
cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build
ctest --test-dir build --output-on-failureFor the SDK adapter, place the macOS SDK's ZoomSDK.framework under
third_party/zoom-sdk/ before configuring. Without it, the SDK-independent
core and tests remain available. CI currently uses Zoom SDK 7.1.5 on both
platforms.
zcomms --list-deviceslists capture/playback devices and reported native channel counts.zcomms-engineexercises the audio engine without a meeting.zcomms-tapdetects test audio on Windows playback endpoints for end-to-end verification.spikes/a-tx-latency/contains the latency measurement harness.
The Windows panel is embedded HTML hosted in WebView2, with a browser-window
fallback. It uses an HTTP control surface on 127.0.0.1:7350: GET / serves
the panel, GET /events streams state with SSE, and POST /act accepts
one-line commands. This interface is for local controls and integrations.
The audio engine is independent of Zoom; the shared talkback layer uses platform-specific SDK adapters. See CLAUDE.md for engineering notes and recorded platform behavior, and docs/PLAN.md for the original architecture rationale. Dated plans include historical designs; the source and current platform status above describe what is implemented.
ZComms' own source is MIT — see LICENSE.
Bundled or fetched dependencies retain their own terms:
- Zoom Meeting SDK: Zoom's license and distribution terms. Supply the SDK separately for source builds; Windows release packages include its runtime.
- speexdsp: BSD-style license; see COPYING.
- miniaudio: public domain or MIT-0, at your choice.
- WebView2: Microsoft's terms; its SDK is fetched during configuration and the Windows loader is packaged with the app.
The MIT license covers ZComms source, not the third-party components. Review those components' terms before redistributing a build.