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# init(pcmFormat:frameCapacity:)

Creates a PCM audio buffer instance for PCM audio data.

```
init?(pcmFormat format: AVAudioFormat, frameCapacity: AVAudioFrameCount)
```

## Parameters

`format`

The format of the PCM audio the buffer contains.

`frameCapacity`

The capacity of the buffer in PCM sample frames.

## Return Value

A new [`AVAudioPCMBuffer`](/documentation/AVFAudio/AVAudioPCMBuffer) instance, or `nil` if it’s not possible.

## Discussion

The method returns `nil` due to the following reasons:

- The format has zero bytes per frame.
- The system can’t represent the buffer byte capacity as an unsigned bit-32 integer.

## See Also

[`frameLength`](/documentation/AVFAudio/AVAudioPCMBuffer/frameLength)

The current number of valid sample frames in the buffer.

[`frameCapacity`](/documentation/AVFAudio/AVAudioPCMBuffer/frameCapacity)

The buffer’s capacity, in audio sample frames.


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