User Facing Delay API

The Public Delay API. More...

Typedefs
typedef struct Delay *	vx_delay
	The delay object. This is like a ring buffer of objects that is maintained by the OpenVX implementation.

Enumerations
enum	vx_delay_attribute_e {   VX_DELAY_TYPE = VX_ATTRIBUTE_BASE(VX_ID_KHRONOS, VX_TYPE_DELAY) + 0x0 ,   VX_DELAY_SLOTS = VX_ATTRIBUTE_BASE(VX_ID_KHRONOS, VX_TYPE_DELAY) + 0x1 }
	The delay attribute list. More...

Functions
VX_API_ENTRY vx_status VX_API_CALL	vxQueryDelay (vx_delay delay, vx_enum attribute, void *ptr, vx_size size)
	Queries a vx_delay object attribute.
VX_API_ENTRY vx_status VX_API_CALL	vxReleaseDelay (vx_delay *delay)
	Releases a reference to a delay object. The object may not be garbage collected until its total reference count is zero.
VX_API_ENTRY vx_delay VX_API_CALL	vxCreateDelay (vx_context context, vx_reference exemplar, vx_size num_slots)
	Creates a Delay object.
VX_API_ENTRY vx_reference VX_API_CALL	vxGetReferenceFromDelay (vx_delay delay, vx_int32 index)
	Retrieves a reference to a delay slot object.
VX_API_ENTRY vx_status VX_API_CALL	vxAgeDelay (vx_delay delay)
	Shifts the internal delay ring by one.

Detailed Description

The Public Delay API.

Typedef Documentation

vx_delay

typedef struct Delay* vx_delay

#include <vx_types.h>

The delay object. This is like a ring buffer of objects that is maintained by the OpenVX implementation.

See also

vxCreateDelay

Enumeration Type Documentation

vx_delay_attribute_e

enum vx_delay_attribute_e

#include <vx_types.h>

The delay attribute list.

Enumerator
VX_DELAY_TYPE	The type of objects in the delay. Read-only. Use a vx_enum parameter.
VX_DELAY_SLOTS	The number of items in the delay. Read-only. Use a vx_size parameter.

Function Documentation

vxAgeDelay()

VX_API_ENTRY vx_status VX_API_CALL vxAgeDelay

(

vx_delay

delay

)

#include <vx_api.h>

Shifts the internal delay ring by one.

This function performs a shift of the internal delay ring by one. This means that, the data originally at index 0 move to index -1 and so forth until index \( -count+1 \). The data originally at index \( -count+1 \) move to index 0. Here \( count \) is the number of slots in delay ring. When a delay is aged, any graph making use of this delay (delay object itself or data objects in delay slots) gets its data automatically updated accordingly.

Parameters

[in]

delay

Returns

A vx_status_e enumeration.

Return values

VX_SUCCESS	Delay was aged; any other value indicates failure.
VX_ERROR_INVALID_REFERENCE	delay is not a valid vx_delay reference.

Examples

optical_flow.cpp.

vxCreateDelay()

VX_API_ENTRY vx_delay VX_API_CALL vxCreateDelay	(	vx_context	context,
		vx_reference	exemplar,
		vx_size	num_slots )

#include <vx_api.h>

Creates a Delay object.

This function creates a delay object with num_slots slots. Each slot contains a clone of the exemplar. The clones only inherit the metadata of the exemplar. The data content of the exemplar is ignored and the clones have their data undefined at delay creation time. The function does not alter the exemplar. Also, it doesn't retain or release the reference to the exemplar.

Note

For the definition of metadata attributes see vxSetMetaFormatAttribute.

Parameters

[in]	context	The reference to the context.
[in]	exemplar	The exemplar object. Supported exemplar object types are: VX_TYPE_ARRAY VX_TYPE_CONVOLUTION VX_TYPE_DISTRIBUTION VX_TYPE_IMAGE VX_TYPE_LUT VX_TYPE_MATRIX VX_TYPE_OBJECT_ARRAY VX_TYPE_PYRAMID VX_TYPE_REMAP VX_TYPE_SCALAR VX_TYPE_THRESHOLD VX_TYPE_TENSOR
[in]	num_slots	The number of objects in the delay. This value must be greater than zero.

Returns

A delay reference vx_delay. Any possible errors preventing a successful creation should be checked using vxGetStatus.

Examples

optical_flow.cpp.

vxGetReferenceFromDelay()

VX_API_ENTRY vx_reference VX_API_CALL vxGetReferenceFromDelay	(	vx_delay	delay,
		vx_int32	index )

#include <vx_api.h>

Retrieves a reference to a delay slot object.

Parameters

[in]	delay	The reference to the delay object.
[in]	index	The index of the delay slot from which to extract the object reference.

Returns

vx_reference. Any possible errors preventing a successful completion of the function should be checked using vxGetStatus.

Note

The delay index is in the range \( [-count+1,0] \). 0 is always the current object.

A reference retrieved with this function must not be given to its associated release API (e.g. vxReleaseImage) unless vxRetainReference is used.

Examples

optical_flow.cpp.

vxQueryDelay()

VX_API_ENTRY vx_status VX_API_CALL vxQueryDelay	(	vx_delay	delay,
		vx_enum	attribute,
		void *	ptr,
		vx_size	size )

#include <vx_api.h>

Queries a vx_delay object attribute.

Parameters

[in]	delay	The reference to a delay object.
[in]	attribute	The attribute to query. Use a vx_delay_attribute_e enumeration.
[out]	ptr	The location at which to store the resulting value.
[in]	size	The size of the container to which ptr points.

Returns

A vx_status_e enumeration.

Return values

VX_SUCCESS	No errors; any other value indicates failure.
VX_ERROR_INVALID_REFERENCE	delay is not a valid vx_delay reference.

vxReleaseDelay()

VX_API_ENTRY vx_status VX_API_CALL vxReleaseDelay

(

vx_delay *

delay

)

#include <vx_api.h>

Releases a reference to a delay object. The object may not be garbage collected until its total reference count is zero.

Parameters

[in]

delay

The pointer to the delay object reference to release.

Postcondition

After returning from this function the reference is zeroed.

Returns

A vx_status_e enumeration.

Return values

VX_SUCCESS	No errors; any other value indicates failure.
VX_ERROR_INVALID_REFERENCE	delay is not a valid vx_delay reference.

Examples

optical_flow.cpp.