C Specification

To enumerate the supported image formats for a specific optical flow usage, call:

// Provided by VK_NV_optical_flow
VkResult vkGetPhysicalDeviceOpticalFlowImageFormatsNV(
    VkPhysicalDevice                            physicalDevice,
    const VkOpticalFlowImageFormatInfoNV*       pOpticalFlowImageFormatInfo,
    uint32_t*                                   pFormatCount,
    VkOpticalFlowImageFormatPropertiesNV*       pImageFormatProperties);

Parameters

  • physicalDevice is the physical device being queried.

  • pOpticalFlowImageFormatInfo is a pointer to a VkOpticalFlowImageFormatInfoNV structure specifying the optical flow usage for which information is returned.

  • pFormatCount is a pointer to an integer related to the number of optical flow properties available or queried, as described below.

  • pImageFormatProperties is a pointer to an array of VkOpticalFlowImageFormatPropertiesNV structures in which supported formats and image parameters are returned.

Description

If pImageFormatProperties is NULL, then the number of optical flow properties supported for the given physicalDevice is returned in pFormatCount. Otherwise, pFormatCount must point to a variable set by the user to the number of elements in the pImageFormatProperties array, and on return the variable is overwritten with the number of values actually written to pImageFormatProperties. If the value of pFormatCount is less than the number of optical flow properties supported, at most pFormatCount values will be written to pImageFormatProperties, and VK_INCOMPLETE will be returned instead of VK_SUCCESS, to indicate that not all the available values were returned.

Before creating an image to be used as a optical flow frame, obtain the supported image creation parameters by querying with vkGetPhysicalDeviceFormatProperties2 and vkGetPhysicalDeviceImageFormatProperties2 using one of the reported formats and adding VkOpticalFlowImageFormatInfoNV to the pNext chain of VkPhysicalDeviceImageFormatInfo2.

When querying the parameters with vkGetPhysicalDeviceImageFormatProperties2 for images used for optical flow operations, the VkOpticalFlowImageFormatInfoNV::usage field must contain one or more of the bits defined in VkOpticalFlowUsageFlagBitsNV.

Valid Usage (Implicit)

  • VUID-vkGetPhysicalDeviceOpticalFlowImageFormatsNV-physicalDevice-parameter
    physicalDevice must be a valid VkPhysicalDevice handle

  • VUID-vkGetPhysicalDeviceOpticalFlowImageFormatsNV-pOpticalFlowImageFormatInfo-parameter
    pOpticalFlowImageFormatInfo must be a valid pointer to a valid VkOpticalFlowImageFormatInfoNV structure

  • VUID-vkGetPhysicalDeviceOpticalFlowImageFormatsNV-pFormatCount-parameter
    pFormatCount must be a valid pointer to a uint32_t value

  • VUID-vkGetPhysicalDeviceOpticalFlowImageFormatsNV-pImageFormatProperties-parameter
    If the value referenced by pFormatCount is not 0, and pImageFormatProperties is not NULL, pImageFormatProperties must be a valid pointer to an array of pFormatCount VkOpticalFlowImageFormatPropertiesNV structures

Return Codes
On success, this command returns

  • VK_SUCCESS

  • VK_INCOMPLETE

On failure, this command returns

  • VK_ERROR_EXTENSION_NOT_PRESENT

  • VK_ERROR_INITIALIZATION_FAILED

  • VK_ERROR_FORMAT_NOT_SUPPORTED

Note

VK_FORMAT_B8G8R8A8_UNORM, VK_FORMAT_R8_UNORM and VK_FORMAT_G8_B8R8_2PLANE_420_UNORM are initially supported for images with optical usage VK_OPTICAL_FLOW_USAGE_INPUT_BIT_NV.

VK_FORMAT_R16G16_SFIXED5_NV is initially supported for images with optical flow usage VK_OPTICAL_FLOW_USAGE_OUTPUT_BIT_NV, VK_OPTICAL_FLOW_USAGE_HINT_BIT_NV and VK_OPTICAL_FLOW_USAGE_GLOBAL_FLOW_BIT_NV.

VK_FORMAT_R8_UINT and VK_FORMAT_R32_UINT are initially supported for images with optical flow usage VK_OPTICAL_FLOW_USAGE_COST_BIT_NV. It is recommended to use VK_FORMAT_R8_UINT because of the lower bandwidth.

See Also

VK_NV_optical_flow, VkOpticalFlowImageFormatInfoNV, VkOpticalFlowImageFormatPropertiesNV, VkPhysicalDevice

Document Notes

For more information, see the Vulkan Specification

This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.

Copyright

Copyright 2014-2024 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0