# VkOpticalFlowSessionCreateFlagBitsNV(3) Manual Page

## Name

VkOpticalFlowSessionCreateFlagBitsNV - Bits specifying flags for optical flow session

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## C Specification

Bits which can be set in VkOpticalFlowSessionCreateInfoNV::`flags`, controlling optical flow session operations, are:

    // Provided by VK_NV_optical_flow
    typedef enum VkOpticalFlowSessionCreateFlagBitsNV {
        VK_OPTICAL_FLOW_SESSION_CREATE_ENABLE_HINT_BIT_NV = 0x00000001,
        VK_OPTICAL_FLOW_SESSION_CREATE_ENABLE_COST_BIT_NV = 0x00000002,
        VK_OPTICAL_FLOW_SESSION_CREATE_ENABLE_GLOBAL_FLOW_BIT_NV = 0x00000004,
        VK_OPTICAL_FLOW_SESSION_CREATE_ALLOW_REGIONS_BIT_NV = 0x00000008,
        VK_OPTICAL_FLOW_SESSION_CREATE_BOTH_DIRECTIONS_BIT_NV = 0x00000010,
    } VkOpticalFlowSessionCreateFlagBitsNV;

## Description

- VK_OPTICAL_FLOW_SESSION_CREATE_ENABLE_HINT_BIT_NV specifies that a VkImageView with external flow vectors will be used as hints in performing the motion search and must be bound to VK_OPTICAL_FLOW_SESSION_BINDING_POINT_HINT_NV.

- VK_OPTICAL_FLOW_SESSION_CREATE_ENABLE_COST_BIT_NV specifies that the cost for the forward flow is generated in a VkImageView which must be bound to VK_OPTICAL_FLOW_SESSION_BINDING_POINT_COST_NV. Additionally, if VK_OPTICAL_FLOW_SESSION_CREATE_BOTH_DIRECTIONS_BIT_NV is also set, the cost for backward flow is generated in a VkImageView which must be bound to VK_OPTICAL_FLOW_SESSION_BINDING_POINT_BACKWARD_COST_NV. The cost is the confidence level of the flow vector for each grid in the frame. The Cost implies how (in)accurate the flow vector is. Higher cost value implies the flow vector to be less accurate and vice-versa.

- VK_OPTICAL_FLOW_SESSION_CREATE_ENABLE_GLOBAL_FLOW_BIT_NV specifies that a global flow vector is estimated from forward flow in a single pixel VkImageView which must be bound to VK_OPTICAL_FLOW_SESSION_BINDING_POINT_GLOBAL_FLOW_NV.

- VK_OPTICAL_FLOW_SESSION_CREATE_ALLOW_REGIONS_BIT_NV specifies that regions of interest can be specified in VkOpticalFlowExecuteInfoNV.

- VK_OPTICAL_FLOW_SESSION_CREATE_BOTH_DIRECTIONS_BIT_NV specifies that backward flow is generated in addition to forward flow which is always generated.

## See Also

VK_NV_optical_flow, VkOpticalFlowSessionCreateFlagsNV

## 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 2014-2026 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0