> ## Documentation Index
> Fetch the complete documentation index at: https://docs.xbox.com/llms.txt
> Use this file to discover all available pages before exploring further.

# XDSP

> XDSP

XDSP APIs (DirectX Math Functions)

## Functions

| Function | Description |
| - | - |
| [ButterflyDIT4\_1](https://docs.xbox.com/reference/audio/xdsp/functions/butterflydit4_1.md) | Don't use; internal use only. |
| [ButterflyDIT4\_4](https://docs.xbox.com/reference/audio/xdsp/functions/butterflydit4_4.md) | Don't use; internal use only. |
| [Deinterleave](https://docs.xbox.com/reference/audio/xdsp/functions/deinterleave.md) | This function deinterleaves audio samples such that all samples corresponding to a specified channel are contiguous. |
| [FFT](https://docs.xbox.com/reference/audio/xdsp/functions/fft.md) | Fast Fourier Transform with an arbitrary number of samples. |
| [FFT4](https://docs.xbox.com/reference/audio/xdsp/functions/fft4.md) | Fast Fourier Transform with four samples. |
| [FFT8](https://docs.xbox.com/reference/audio/xdsp/functions/fft8.md) | Fast Fourier Transform with eight samples. |
| [FFT16](https://docs.xbox.com/reference/audio/xdsp/functions/fft16.md) | Fast Fourier Transform with 16 samples. |
| [FFTInitializeUnityTable](https://docs.xbox.com/reference/audio/xdsp/functions/fftinitializeunitytable.md) | Initializes unity roots lookup table used by Fast Fourier Transform functions. |
| [FFTInterleaved](https://docs.xbox.com/reference/audio/xdsp/functions/fftinterleaved.md) | Applies a 2<sup>N</sup>-sample Fast Fourier Transform (FFT), and it unswizzles the result such that the samples are arranged by increasing frequency. Audio is first deinterleaved if it is multichannel. |
| [FFTPolar](https://docs.xbox.com/reference/audio/xdsp/functions/fftpolar.md) | Converts complex components into their polar form. |
| [FFTUnswizzle](https://docs.xbox.com/reference/audio/xdsp/functions/fftunswizzle.md) | This function arranges the output of the Fast Fourier Transform function by increasing frequency. |
| [IFFTDeinterleaved](https://docs.xbox.com/reference/audio/xdsp/functions/ifftdeinterleaved.md) | This function applies a 2<sup>N</sup>-sample inverse Fast Fourier Transform. Audio is first interleaved if it is multichannel. |
| [Interleave](https://docs.xbox.com/reference/audio/xdsp/functions/interleave.md) | This function interleaves audio samples such that all samples corresponding to a specified frame are contiguous. |
| [ISPOWEROF2](https://docs.xbox.com/reference/audio/xdsp/functions/ispowerof2.md) | Don't use; internal use only. |
| [vmulComplex function](https://docs.xbox.com/reference/audio/xdsp/functions/vmulcomplex.md) | Don't use; internal use only. |
| [vmulComplex](https://docs.xbox.com/reference/audio/xdsp/functions/vmulcomplex_2.md) | Don't use; internal use only. |


## Related topics

- [XDSP audio](https://docs.xbox.com/reference/audio/xdspaudio/xdspaudio_members.md)
- [XDSP Errors](https://docs.xbox.com/reference/audio/xdspaudio/enums/xdsperrors.md)
- [XDSP overview](https://docs.xbox.com/build/console-features/audio/overviews/xdsp-overview.md)
- [XDSP Enveloping Overview](https://docs.xbox.com/build/console-features/audio/overviews/xdsp-overview-enveloping.md)
- [XDSP Impulse Response Reduction Overview](https://docs.xbox.com/build/console-features/audio/overviews/xdsp-overview-ir-reduction.md)