---
title: isRenderingOffline
framework: audiotoolbox
role: symbol
role_heading: Instance Property
path: audiotoolbox/auaudiounit/isrenderingoffline
---

# isRenderingOffline

Communicates to an audio unit that it is rendering offline.

## Declaration

```swift
var isRenderingOffline: Bool { get set }
```

## Discussion

Discussion A host should use this property when using an audio unit in a context where there are no realtime deadlines. An audio unit may respond by using a more expensive signal processing algorithm, or allowing itself to block at render time if data being generated on secondary work threads is not ready in time. This version 3 property is bridged to the version 2 kAudioUnitProperty_OfflineRender API.

## See Also

### Optimizing Performance

- [latency](audiotoolbox/auaudiounit/latency.md)
- [tailTime](audiotoolbox/auaudiounit/tailtime.md)
- [renderQuality](audiotoolbox/auaudiounit/renderquality.md)
- [shouldBypassEffect](audiotoolbox/auaudiounit/shouldbypasseffect.md)
- [canProcessInPlace](audiotoolbox/auaudiounit/canprocessinplace.md)