# System Video Input

System Video Input lets OmniScope use OS-level capture devices such as webcams and USB capture hardware.

## Supported Devices

| Device Type       | Examples                                 |
| ----------------- | ---------------------------------------- |
| Webcams           | Built-in cameras, Logitech, Razer        |
| USB Capture Cards | AJA U-TAP, Elgato Cam Link, Magewell     |
| HDMI/SDI to USB   | Blackmagic Web Presenter, Atomos Connect |
| Virtual Cameras   | OBS Virtual Camera, NDI Virtual Input    |

## Platform Notes

### macOS

OmniScope uses AVFoundation-based system capture.

Since 1.11.25, USB capture on macOS was rewritten with better hot-plug handling and synchronized audio support. In 1.11.37, audio monitoring for USB capture devices (e.g. AJA U-Tap) was further improved to stay in sync with live video cadence, avoiding missing, looped, or malformed audio.

### Windows

Since 1.11.25, Windows system capture supports a DirectShow path for broader USB device compatibility and improved MJPEG capture behavior.

## USB Driver Choice (Windows)

In **Options > Preferences > Sources**, choose the USB capture driver:

* **Media Foundation**
* **DirectShow**

Changing this setting requires an app restart.

## Audio Support

{% hint style="info" %}
**1.11.25+** - USB input audio is supported on both macOS and Windows.
{% endhint %}

For devices with embedded or associated audio:

1. Select the video device.
2. Confirm the audio source in input settings.
3. Use the Audio Meter scope to verify levels.

### System Audio Capture

You can also capture system audio from your computer output:

1. Open input settings.
2. Enable **System Audio**.
3. Choose the audio output/source to monitor.

## Troubleshooting

### Device not listed

* Reconnect the device and verify OS detection.
* Close other apps that may hold exclusive access.
* Check camera permissions on macOS.
* Check Device Manager on Windows.

### No audio

* Confirm the device actually carries audio.
* Verify selected audio source in input settings.
* Check OS-level microphone/audio permissions.

### Unstable performance

* Lower resolution or frame rate.
* Prefer USB 3.0+ ports.
* Use vendor-native integrations (DeckLink/AJA) for high-end workflows.

## Related

* [Screen Capture](/nobe-omniscope/sources/screen-capture.md)
* [DeckLink & UltraStudio](/nobe-omniscope/sources/decklink-and-ultrastudio.md)
* [AJA](/nobe-omniscope/sources/aja.md)


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