vkCmdControlVideoCodingKHR(3)

# vkCmdControlVideoCodingKHR(3) Manual Page

## Name

vkCmdControlVideoCodingKHR - Control video coding parameters

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## C Specification

To apply dynamic controls to the currently bound video session object, call:

    // Provided by VK_KHR_video_queue
    void vkCmdControlVideoCodingKHR(
        VkCommandBuffer                             commandBuffer,
        const VkVideoCodingControlInfoKHR*          pCodingControlInfo);

## Parameters

- `commandBuffer` is the command buffer in which to record the command.

- `pCodingControlInfo` is a pointer to a VkVideoCodingControlInfoKHR structure specifying the control parameters.

## Description

The control parameters provided in this call are applied to the video session at the time the command executes on the device and are in effect until a subsequent call to this command with the same video session bound changes the corresponding control parameters.

A newly created video session must be reset before performing video coding operations using it by including `VK_VIDEO_CODING_CONTROL_RESET_BIT_KHR` in `pCodingControlInfo->flags`. The reset operation also returns all DPB slots of the video session to the inactive state. Correspondingly, any DPB slot index associated with the bound reference picture resources is removed.

For encode sessions, the reset operation returns rate control configuration to implementation default settings and sets the video encode quality level to zero.

After video coding operations are performed using a video session, the reset operation can be used to return the video session to the same initial state as after the reset of a newly created video session. This can be used, for example, when different video sequences are needed to be processed with the same video session object.

If `pCodingControlInfo->flags` includes `VK_VIDEO_CODING_CONTROL_ENCODE_RATE_CONTROL_BIT_KHR`, then the command replaces the rate control configuration maintained by the video session with the configuration specified in the VkVideoEncodeRateControlInfoKHR structure included in the `pCodingControlInfo->pNext` chain.

If `pCodingControlInfo->flags` includes `VK_VIDEO_CODING_CONTROL_ENCODE_QUALITY_LEVEL_BIT_KHR`, then the command changes the current video encode quality level to the value specified in the `qualityLevel` member of the VkVideoEncodeQualityLevelInfoKHR structure included in the `pCodingControlInfo->pNext` chain.

Valid Usage

- VUID-vkCmdControlVideoCodingKHR-flags-07017
  If `pCodingControlInfo->flags` does not include `VK_VIDEO_CODING_CONTROL_RESET_BIT_KHR`, then the bound video session must not be in uninitialized state at the time the command is executed on the device

- VUID-vkCmdControlVideoCodingKHR-pCodingControlInfo-08243
  If the bound video session was not created with an encode operation, then `pCodingControlInfo->pNext` must not include `VK_VIDEO_CODING_CONTROL_ENCODE_RATE_CONTROL_BIT_KHR` or `VK_VIDEO_CODING_CONTROL_ENCODE_QUALITY_LEVEL_BIT_KHR`

Valid Usage (Implicit)

- VUID-vkCmdControlVideoCodingKHR-commandBuffer-parameter
  `commandBuffer` must be a valid VkCommandBuffer handle

- VUID-vkCmdControlVideoCodingKHR-pCodingControlInfo-parameter
  `pCodingControlInfo` must be a valid pointer to a valid VkVideoCodingControlInfoKHR structure

- VUID-vkCmdControlVideoCodingKHR-commandBuffer-recording
  `commandBuffer` must be in the recording state

- VUID-vkCmdControlVideoCodingKHR-commandBuffer-cmdpool
  The `VkCommandPool` that `commandBuffer` was allocated from must support decode, or encode operations

- VUID-vkCmdControlVideoCodingKHR-renderpass
  This command must only be called outside of a render pass instance

- VUID-vkCmdControlVideoCodingKHR-videocoding
  This command must only be called inside of a video coding scope

- VUID-vkCmdControlVideoCodingKHR-bufferlevel
  `commandBuffer` must be a primary `VkCommandBuffer`

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Video Coding Scope | Supported Queue Types | Command Type
--- | --- | --- | --- | ---
Primary | Outside | Inside | Decode Encode | Action

## See Also

VK_KHR_video_queue, VkCommandBuffer, VkVideoCodingControlInfoKHR

## 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 2014-2023 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0