---
title: "setPreferredIOBufferDuration(_:)"
framework: avfaudio
role: symbol
role_heading: Instance Method
path: "avfaudio/avaudiosession/setpreferrediobufferduration(_:)"
---

# setPreferredIOBufferDuration(_:)

Sets the preferred audio I/O buffer duration.

## Declaration

```swift
func setPreferredIOBufferDuration(_ duration: TimeInterval) throws
```

## Parameters

- `duration`: The audio I/O buffer duration, in seconds, that you want to use.

## Discussion

Discussion This method requests a change to the I/O buffer duration. To determine whether the change has taken effect, use the ioBufferDuration property. The audio I/O buffer duration is the number of seconds for a single audio input/output cycle. For example, with an I/O buffer duration of 0.005 s, on each audio I/O cycle: You receive 0.005 s of audio if obtaining input. You must provide 0.005 s of audio if providing output. The typical maximum I/O buffer duration is 0.093 seconds (corresponding to 4,096 sample frames at a sample rate of 44.1 kHz). The minimum I/O buffer duration is at least 0.005 seconds (256 frames) but might be lower depending on the hardware in use. You can set a preferred I/O buffer duration before or after activating the audio session.

## See Also

### Configuring I/O buffer duration

- [ioBufferDuration](avfaudio/avaudiosession/iobufferduration.md)
- [preferredIOBufferDuration](avfaudio/avaudiosession/preferrediobufferduration.md)