Fast Fourier Transform

Operations that applies the Fast Fourier Transform and its inverse to 2D images. More...

Functions
VPIStatus	vpiCreateFFT (uint32_t backends, int32_t inputWidth, int32_t inputHeight, const VPIImageFormat inFormat, const VPIImageFormat outFormat, VPIPayload *payload)
	Creates payload for direct Fast Fourier Transform algorithm. More...
VPIStatus	vpiSubmitFFT (VPIStream stream, uint32_t backend, VPIPayload payload, VPIImage input, VPIImage output, uint32_t flags)
	Runs the direct Fast Fourier Transform on single image. More...
VPIStatus	vpiCreateIFFT (uint32_t backends, int32_t outputWidth, int32_t outputHeight, const VPIImageFormat inFormat, const VPIImageFormat outFormat, VPIPayload *payload)
	Creates payload for inverse Fast Fourier Transform algorithm. More...
VPIStatus	vpiSubmitIFFT (VPIStream stream, uint32_t backend, VPIPayload payload, VPIImage input, VPIImage output, uint32_t flags)
	Runs the inverse Fast Fourier Transform on single image. More...

Detailed Description

Operations that applies the Fast Fourier Transform and its inverse to 2D images.

Both FFT and inverse FFT need a payload created during application initialization phase, where image dimensions, input and output types are defined. The payload then can be used to submit operations on different images, as long as their dimensions and types match what was defined during payload creation.

Function Documentation

vpiCreateFFT()

VPIStatus vpiCreateFFT	(	uint32_t	backends,
		int32_t	inputWidth,
		int32_t	inputHeight,
		const VPIImageFormat	inFormat,
		const VPIImageFormat	outFormat,
		VPIPayload *	payload
	)

#include <vpi/algo/FFT.h>

Creates payload for direct Fast Fourier Transform algorithm.

The created payload can then be used with vpiSubmitFFT.

Parameters

[in]	backends	VPI backends that are eligible to execute the algorithm. Currently only one backend is accepted.
[in]	inputWidth,inputHeight	Dimensions of the input/output images to be used.
[in]	inFormat	Input image format.
[in]	outFormat	Output image format.
[out]	payload	Pointer to memory where the created payload handle will be written to.

Returns

an error code on failure else VPI_SUCCESS.

vpiCreateIFFT()

VPIStatus vpiCreateIFFT	(	uint32_t	backends,
		int32_t	outputWidth,
		int32_t	outputHeight,
		const VPIImageFormat	inFormat,
		const VPIImageFormat	outFormat,
		VPIPayload *	payload
	)

#include <vpi/algo/FFT.h>

Creates payload for inverse Fast Fourier Transform algorithm.

The created payload can then be used with vpiSubmitIFFT.

Parameters

[in]	backends	VPI backends that are eligible to execute the algorithm. Currently only one backend is accepted.
[in]	outputWidth,outputHeight	Output image dimensions.
[in]	inFormat	Input image format.
[in]	outFormat	Output image format.
[out]	payload	Pointer to memory where the created payload handle will be written to.

Returns

an error code on failure else VPI_SUCCESS

vpiSubmitFFT()

VPIStatus vpiSubmitFFT	(	VPIStream	stream,
		uint32_t	backend,
		VPIPayload	payload,
		VPIImage	input,
		VPIImage	output,
		uint32_t	flags
	)

#include <vpi/algo/FFT.h>

Runs the direct Fast Fourier Transform on single image.

Parameters

[in]	stream	The stream where the operation will be queued in.
[in]	backend	Backend that will execute the algorithm. Must be one of the backends specified during payload creation. If 0, VPI will select one of the eligible backends from the payload that accepts the given parameters, usually the fastest one.
[in]	payload	Payload created with vpiCreateFFT
[in]	input	Input image in space domain.
[out]	output	Image where the result in frequency domain will be written to.
[in]	flags	Control flags, currently it must be set to 0.

Returns

an error code on failure else VPI_SUCCESS

vpiSubmitIFFT()

VPIStatus vpiSubmitIFFT	(	VPIStream	stream,
		uint32_t	backend,
		VPIPayload	payload,
		VPIImage	input,
		VPIImage	output,
		uint32_t	flags
	)

#include <vpi/algo/FFT.h>

Runs the inverse Fast Fourier Transform on single image.

Parameters

[in]	stream	A stream handle where the operation will be queued in.
[in]	backend	Backend that will execute the algorithm. Must be one of the backends specified during payload creation. If 0, VPI will select one of the eligible backends from the payload that accepts the given parameters, usually the fastest one.
[in]	payload	Payload created with vpiCreateIFFT
[in]	input	Input image in frequency domain.
[out]	output	Image where the result in space domain will be written to.
[in]	flags	Control flags. Valid values: 0 for default processing, where output scaled. VPI_DENORMALIZED_OUTPUT : Output is left denormalized. This leads to faster execution as normalization isn't usually needed. Absense of this flag will scale the output, dividing it by the total pixel count. This makes the output the exact inverse of direct Fast Fourier Transform.

Returns

an error code on failure else VPI_SUCCESS