Fast Fourier Transform

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

Functions
VPIStatus	vpiCreateFFT (uint64_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, uint64_t backend, VPIPayload payload, VPIImage input, VPIImage output, uint64_t flags)
	Runs the direct Fast Fourier Transform on single image. More...
VPIStatus	vpiCreateIFFT (uint64_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, uint64_t backend, VPIPayload payload, VPIImage input, VPIImage output, uint64_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.

Refer to FFT for more details and usage examples regarding FFT.

Refer to Inverse FFT for more details and usage examples regarding IFFT.

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

Function Documentation

vpiCreateFFT()

VPIStatus vpiCreateFFT	(	uint64_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.

Attention

For this function to succeed, it is required that the library libcufft.so.12 is installed in the system.

Parameters

[in]	backends	VPI backend that will execute the algorithm. Valid values: VPI_BACKEND_CPU VPI_BACKEND_CUDA Backend must be enabled in current context.
[in]	inputWidth,inputHeight	Dimensions of the input/output images to be used. Must be >= 1x1. With CPU backend, image width must be even.
[in]	inFormat	Input image format. Supported formats: VPI_IMAGE_FORMAT_F32, real input. VPI_IMAGE_FORMAT_2F32, complex input.
[in]	outFormat	Output image format. Supported format: VPI_IMAGE_FORMAT_2F32, complex output.
[out]	payload	Pointer to the payload variable that receives the created handle.

Return values

VPI_ERROR_INVALID_ARGUMENT	payload is NULL.
VPI_ERROR_INVALID_ARGUMENT	inputWidth or inputHeight outside valid range.
VPI_ERROR_INVALID_ARGUMENT	backend refers to an invalid backend.
VPI_ERROR_NOT_IMPLEMENTED	FFT algorithm is not supported by given backend.
VPI_ERROR_INVALID_CONTEXT	Current context is destroyed.
VPI_IMAGE_FORMAT_INVALID	outFormat is not supported.
VPI_ERROR_OUT_OF_MEMORY	Cannot allocate required resources.
VPI_ERROR_INVALID_OPERATION	Backend isn't enabled in current context.
VPI_ERROR_INVALID_OPERATION	Library libcufft.so.12 isn't installed in the system.
VPI_SUCCESS	Operation executed successfully.

vpiSubmitFFT()

VPIStatus vpiSubmitFFT	(	VPIStream	stream,
		uint64_t	backend,
		VPIPayload	payload,
		VPIImage	input,
		VPIImage	output,
		uint64_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. Must not be NULL. Stream must have enabled the backends that will execute the algorithm.
[in]	backend	Backend that will execute the algorithm. Must be the backend specified during payload creation or 0 as a shorthand to use this backend.
[in]	payload	Payload created with vpiCreateFFT
[in]	input	Input image in space domain. Must not be NULL. Must have same format and dimensions as the one specified during payload creation. Image must have enabled the backends that will execute the algorithm. When using the CPU backend, input rows must be aligned to 4 bytes.
[out]	output	Image where the result in frequency domain will be written to. The top left pixel of the output represents the DC (0 Hz) component. Must not be NULL. Must have same format as the one specified during payload creation. Image must have enabled the backends that will execute the algorithm. When using the CPU backend, output rows must be aligned to 4 bytes. Output dimensions depends on input's based on input's format, as shown below: Input Format Output Size VPI_IMAGE_FORMAT_2F32 W x H VPI_IMAGE_FORMAT_F32 floor(W/2)+1 x H When input is real, output contains only the left half of the full Hermitian (symmetric-conjugate).
[in]	flags	Control flags. Currently it must be 0.

Return values

VPI_ERROR_INVALID_ARGUMENT	stream is NULL.
VPI_ERROR_INVALID_ARGUMENT	input or output are NULL.
VPI_ERROR_INVALID_ARGUMENT	payload is not created using vpiCreateFFT.
VPI_ERROR_INVALID_ARGUMENT	input image dimension and format does not match the ones associated with payload.
VPI_ERROR_INVALID_ARGUMENT	output image format does not match the one associated with payload.
VPI_ERROR_INVALID_ARGUMENT	Non-supported flags.
VPI_ERROR_INVALID_ARGUMENT	output dimensions are non-conformant with input's.
VPI_ERROR_INVALID_PAYLOAD_TYPE	payload is invalid.
VPI_ERROR_INVALID_OPERATION	The needed backends aren't enabled in stream, input or output.
VPI_SUCCESS	Operation executed successfully.

vpiCreateIFFT()

VPIStatus vpiCreateIFFT	(	uint64_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.

Attention

For this function to succeed, it is required that the library libcufft.so.12 is installed in the system.

Parameters

[in]	backends	VPI backend that will execute the algorithm. Valid values: VPI_BACKEND_CPU VPI_BACKEND_CUDA Backend must be enabled in current context.
[in]	outputWidth,outputHeight	Output image dimensions. Must be >= 1.
[in]	inFormat	Input image format. Supported format: VPI_IMAGE_FORMAT_2F32, complex input.
[in]	outFormat	Output image format. Must have same format as the one specified during payload creation. With CPU backend, output width must be even. Supported formats: VPI_IMAGE_FORMAT_F32, real output. VPI_IMAGE_FORMAT_2F32, complex output.
[out]	payload	Pointer to the payload variable that receives the created handle.

Return values

VPI_ERROR_INVALID_ARGUMENT	payload is NULL.
VPI_ERROR_INVALID_ARGUMENT	outputWidth or outputHeight outside valid range.
VPI_ERROR_INVALID_ARGUMENT	backends refers to an invalid backend.
VPI_ERROR_NOT_IMPLEMENTED	IFFT algorithm is not supported by given backend.
VPI_ERROR_INVALID_CONTEXT	Current context is destroyed.
VPI_IMAGE_FORMAT_INVALID	outFormat is not supported.
VPI_ERROR_OUT_OF_MEMORY	Cannot allocate required resources.
VPI_ERROR_INVALID_OPERATION	Backend isn't enabled in current context.
VPI_ERROR_INVALID_OPERATION	Library libcufft.so.12 isn't installed in the system.
VPI_SUCCESS	Operation executed successfully.

vpiSubmitIFFT()

VPIStatus vpiSubmitIFFT	(	VPIStream	stream,
		uint64_t	backend,
		VPIPayload	payload,
		VPIImage	input,
		VPIImage	output,
		uint64_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. Must not be NULL. Stream must have enabled the backends that will execute the algorithm.
[in]	backend	Backend that will execute the algorithm. Must be the backend specified during payload creation or 0 as a shorthand to use this backend.
[in]	payload	Payload created with vpiCreateIFFT
[in]	input	Input image in frequency domain. The top left pixel of the input represents the DC (0 Hz) component. Must not be NULL. Must have same format and dimensions as the one specified during payload creation. Image must have enabled the backends that will execute the algorithm. When using the CPU backend, input rows must be aligned to 4 bytes. When output is real, input contains only the left half of the full Hermitian (symmetric-conjugate). Input dimensions depends on output's based on output's format, as shown below: Output Format Input Size VPI_IMAGE_FORMAT_2F32 W x H VPI_IMAGE_FORMAT_F32 floor(W/2)+1 x H
[out]	output	Image where the result in space domain will be written to. Must not be NULL. Must have same format as the one specified during payload creation. Image must have enabled the backends that will execute the algorithm. When using the CPU backend, output rows must be aligned to 4 bytes.
[in]	flags	Control flags. Valid values are a combination of one or more of the following flags: 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. Absence 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.

Return values

VPI_ERROR_INVALID_ARGUMENT	stream is NULL.
VPI_ERROR_INVALID_ARGUMENT	input or output are NULL.
VPI_ERROR_INVALID_ARGUMENT	payload is not created using vpiCreateIFFT.
VPI_ERROR_INVALID_ARGUMENT	input image dimension and format does not match the ones associated with payload.
VPI_ERROR_INVALID_ARGUMENT	output image format does not match the one associated with payload.
VPI_ERROR_INVALID_ARGUMENT	flags includes a non-supported flag.
VPI_ERROR_INVALID_ARGUMENT	output dimensions are non-conformant with input's.
VPI_ERROR_INVALID_PAYLOAD_TYPE	payload is invalid.
VPI_ERROR_INVALID_OPERATION	The needed backends aren't enabled in stream, input or output.
VPI_SUCCESS	Operation executed successfully.