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# AudioConverterFillBuffer

```
extern OSStatus AudioConverterFillBuffer(AudioConverterRef inAudioConverter, AudioConverterInputDataProc inInputDataProc, void *inInputDataProcUserData, UInt32 *ioOutputDataSize, void *outOutputData);
```

## Parameters

`inAudioConverter`

The audio converter to use for format conversion.

`inInputDataProc`

A callback function that supplies audio data to convert. This callback is invoked repeatedly as the converter is ready for new input data.

`inInputDataProcUserData`

Custom data for use by your application when receiving a callback invocation.

`ioOutputDataSize`

On input, the size, in bytes, of the buffer available for the converted data. On output, the number of bytes written to the output buffer (pointed to by the `outOutputData` parameter).

`outOutputData`

On output, the converted audio data.

## Return Value

A  result code.

## Discussion

Converts audio data supplied by a callback function.

### Special Considerations

This function is deprecated. Use the [`AudioConverterFillComplexBuffer(_:_:_:_:_:_:)`](/documentation/AudioToolbox/AudioConverterFillComplexBuffer(_:_:_:_:_:_:)) function instead.

---

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