# System Audio Capture

{% hint style="info" %}
Requires **macOS 14.4** or later. Windows support uses WASAPI.
{% endhint %}

System Audio Capture lets OmniScope monitor your computer's audio output without any external cabling. Audio from any application — DAW, NLE, media player — is captured directly and fed into OmniScope's **Audio Meter** and **Goniometer** scopes for real-time analysis.

<figure><img src="/files/CrmFUihI7r9tyqPSHH0S" alt=""><figcaption><p>System Audio Capture window</p></figcaption></figure>

## How It Works

OmniScope taps into the system's audio output device using platform-native APIs:

| Platform    | Technology                        | Minimum Version |
| ----------- | --------------------------------- | --------------- |
| **macOS**   | Core Audio Tap (ScreenCaptureKit) | macOS 14.4      |
| **Windows** | WASAPI loopback capture           | Windows 10      |

The captured audio is delivered as **32-bit float** samples at **48 kHz stereo** and routed to OmniScope's audio pipeline — the same path used by hardware audio sources.

## Opening System Audio Capture

Open the window from the **Options** menu or the toolbar:

**Options > System Audio Capture**

## Controls

| Control                  | Description                                                                                   |
| ------------------------ | --------------------------------------------------------------------------------------------- |
| **Start / Stop Capture** | Begin or end system audio capture. On macOS, the first start may trigger a permission prompt. |
| **Output Device**        | Select which audio output device to tap. Defaults to the system's current output device.      |

## Audio Meter & Statistics

While capturing, the window displays:

* **Audio meter** — real-time L/R peak meters with hold indicators and dB readout
* **Audio format** — sample rate and channel count
* **Statistics** — frames captured, buffer overruns, capture latency, and processing load

## macOS Permissions

On macOS 14.4+, system audio capture requires **Screen & System Audio Recording** permission. If permission has not been granted:

1. Click **Start Capture** — macOS will prompt you to allow access
2. If previously denied, click **Open System Settings** and enable OmniScope under **Privacy & Security > Screen & System Audio Recording**

## WAV Dump (Debug)

For diagnostic purposes, you can record captured audio to a WAV file:

1. Enter a file path in the **WAV Dump** section
2. Set the **Max Seconds** limit (1–120 seconds)
3. Click **Start WAV Dump** to begin recording

The output is a 32-bit float PCM WAV file.

## Use Cases

* **Audio QC without hardware routing** — monitor loudness, stereo imaging, and phase directly from your NLE or DAW output
* **Remote review sessions** — combine system audio capture with NDI output to stream both video scopes and audio analysis to a remote client
* **Quick A/V sync checks** — pair system audio with a video source to verify lip sync without dedicated audio I/O

## Related

* [Audio Meter](/nobe-omniscope/scopes/audio-meter.md)
* [Goniometer](/nobe-omniscope/scopes/goniometer.md)


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