---
title: "init(streamDescription:)"
framework: avfaudio
role: symbol
role_heading: Initializer
path: "avfaudio/avaudioformat/init(streamdescription:)"
---

# init(streamDescription:)

Creates an audio format instance from a stream description.

## Declaration

```swift
init?(streamDescription asbd: UnsafePointer<AudioStreamBasicDescription>)
```

## Parameters

- `asbd`: The audio stream description.

## Return Value

Return Value A new AVAudioFormat instance, or nil if the initialization fails.

## Discussion

Discussion If the AudioStreamBasicDescription specifies more than two channels, this method fails and returns nil. Instead, use the init(streamDescription:channelLayout:) method.

## See Also

### Creating a New Audio Format Representation

- [init(standardFormatWithSampleRate:channelLayout:)](avfaudio/avaudioformat/init(standardformatwithsamplerate:channellayout:).md)
- [init(standardFormatWithSampleRate:channels:)](avfaudio/avaudioformat/init(standardformatwithsamplerate:channels:).md)
- [init(commonFormat:sampleRate:channels:interleaved:)](avfaudio/avaudioformat/init(commonformat:samplerate:channels:interleaved:).md)
- [init(commonFormat:sampleRate:interleaved:channelLayout:)](avfaudio/avaudioformat/init(commonformat:samplerate:interleaved:channellayout:).md)
- [init(settings:)](avfaudio/avaudioformat/init(settings:).md)
- [init(streamDescription:channelLayout:)](avfaudio/avaudioformat/init(streamdescription:channellayout:).md)
- [init(formatDescription:)](avfaudio/avaudioformat/init(formatdescription:).md)
- [init(cmAudioFormatDescription:)](avfaudio/avaudioformat/init(cmaudioformatdescription:)-8rdfj.md)