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# IFFTDeinterleaved

> IFFTDeinterleaved

# IFFTDeinterleaved

This function applies a 2<sup>N</sup>-sample inverse Fast Fourier Transform (FFT). Audio is interleaved first if it is multichannel.

## Syntax

```cpp theme={null}
void DSP::IFFTDeinterleaved(  
         XMVECTOR* __restrict pReal,  
         XMVECTOR* __restrict pImaginary,  
         const XMVECTOR* __restrict pUnityTable,  
         const size_t uChannelCount,  
         const size_t uLog2Length  
)  
```

### Parameters

*pReal*   \_Inout\_updates\_(((1 \<\< uLog2Length) \* uChannelCount) / 4)\
Type: XMVECTOR\* \_\_restrict

Real components of the FFT. It must have at least (1 \<\< *uLog2Length* × *uChannelCount*) ÷ 4 elements.

*pImaginary*   \_Inout\_updates\_(((1 \<\< uLog2Length) \* uChannelCount) / 4)\
Type: XMVECTOR\* \_\_restrict

Imaginary components of the FFT. It must have at least (1 \<\< *uLog2Length* × *uChannelCount*) ÷ 4 elements.

*pUnityTable*   \_In\_reads\_(1 \<\< uLog2Length)\
Type: XMVECTOR\* \_\_restrict

Unity table that is used by the FFT. It must have at least (1 \<\< *uLog2Length*) elements. See [FFTInitializeUnityTable](/reference/audio/xdsp/functions/fftinitializeunitytable) for more information.

*uChannelCount*   \_In\_\
Type: size\_t

Number of channels in the FFT. *uChannelCount* must be greater than zero.

*uLog2Length*   \_In\_\
Type: size\_t

Base-2 log of the FFT length, in frames. *uLog2Length* must be within \[2, 10].

### Return value

Type: void

None.

## Remarks

Use the FFIntializeUnityTable function to initialize the *pUnityTable* parameter. The memory for *pReal*, *pImaginary*, and *pUnityTable* parameters must not overlap. *pReal* will be updated with the result of the FFT when the function returns.

## Requirements

**Header:** xdsp.h

**Supported platforms:** XBOX One family consoles and XBOX Series consoles

## See also

[xdsp](/reference/audio/xdsp/xdsp_members)

[FFTInitializeUnityTable](/reference/audio/xdsp/functions/fftinitializeunitytable)

[Game for Windows and the DirectX SDK blog](https://walbourn.github.io/xdsp-h-digital-signal-processing-helper-functions/)


## Related topics

- [XDspActivationOptions](/reference/audio/xdspaudio/enums/xdspactivationoptions.md)
- [XApuConnectOptions](/reference/audio/xapu/enums/xapuconnectoptions.md)
- [FFTInterleaved](/reference/audio/xdsp/functions/fftinterleaved.md)
- [GetShapeDmaNumBytes](/reference/audio/shapedmacontext/functions/getshapedmanumbytes.md)
- [SHAPE_PCM_MODE](/reference/audio/shapepcmcontext/enums/shape_pcm_mode.md)