C Specification
The VkVideoEncodeAV1RateControlLayerInfoKHR
structure is defined as:
// Provided by VK_KHR_video_encode_av1
typedef struct VkVideoEncodeAV1RateControlLayerInfoKHR {
VkStructureType sType;
const void* pNext;
VkBool32 useMinQIndex;
VkVideoEncodeAV1QIndexKHR minQIndex;
VkBool32 useMaxQIndex;
VkVideoEncodeAV1QIndexKHR maxQIndex;
VkBool32 useMaxFrameSize;
VkVideoEncodeAV1FrameSizeKHR maxFrameSize;
} VkVideoEncodeAV1RateControlLayerInfoKHR;
Members
-
sType
is a VkStructureType value identifying this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
useMinQIndex
indicates whether the quantizer index values determined by rate control will be clamped to the lower bounds on the quantizer index values specified inminQIndex
. -
minQIndex
specifies the lower bounds on the quantizer index values, for each rate control group, that the implementation’s rate control algorithm will use whenuseMinQIndex
is set toVK_TRUE
. -
useMaxQIndex
indicates whether the quantizer index values determined by rate control will be clamped to the upper bounds on the quantizer index values specified inmaxQIndex
. -
maxQIndex
specifies the upper bounds on the quantizer index values, for each rate control group, that the implementation’s rate control algorithm will use whenuseMaxQIndex
is set toVK_TRUE
. -
useMaxFrameSize
indicates whether the implementation’s rate control algorithm should use the values specified inmaxFrameSize
as the upper bounds on the encoded frame size for each rate control group. -
maxFrameSize
specifies the upper bounds on the encoded frame size, for each rate control group, whenuseMaxFrameSize
is set toVK_TRUE
.
Description
When used, the values in minQIndex
and maxQIndex
guarantee that
the effective quantizer index values used by the implementation will respect
those lower and upper bounds, respectively.
However, limiting the range of quantizer index values that the
implementation is able to use will also limit the capabilities of the
implementation’s rate control algorithm to comply to other constraints.
In particular, the implementation may not be able to comply to the
following:
-
The average and/or peak bitrate values to be used for the encoded bitstream specified in the
averageBitrate
andmaxBitrate
members of the VkVideoEncodeRateControlLayerInfoKHR structure. -
The upper bounds on the encoded frame size, for each rate control group, specified in the
maxFrameSize
member ofVkVideoEncodeAV1RateControlLayerInfoKHR
.
Note
|
In general, applications need to configure rate control parameters appropriately in order to be able to get the desired rate control behavior, as described in the Video Encode Rate Control section. |
When an instance of this structure is included in the pNext
chain of a
VkVideoEncodeRateControlLayerInfoKHR structure specified in one of the
elements of the pLayers
array member of the
VkVideoEncodeRateControlInfoKHR structure passed to the
vkCmdControlVideoCodingKHR command,
VkVideoCodingControlInfoKHR::flags
includes
VK_VIDEO_CODING_CONTROL_ENCODE_RATE_CONTROL_BIT_KHR
, and the bound
video session was created with the video codec operation
VK_VIDEO_CODEC_OPERATION_ENCODE_AV1_BIT_KHR
, it specifies the
AV1-specific rate control parameters of the rate control layer corresponding
to that element of pLayers
.
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.