C Specification

VkSamplerYcbcrModelConversion defines the conversion from the source color model to the shader color model. Possible values are:

typedef enum VkSamplerYcbcrModelConversion {
    VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY = 0,
    VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY = 1,
    VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709 = 2,
    VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601 = 3,
    VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020 = 4,
    VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY_KHR = VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY,
    VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY_KHR = VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY,
    VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709_KHR = VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709,
    VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601_KHR = VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601,
    VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020_KHR = VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020,
    VK_SAMPLER_YCBCR_MODEL_CONVERSION_MAX_ENUM = 0x7FFFFFFF
} VkSamplerYcbcrModelConversion;

or the equivalent

typedef VkSamplerYcbcrModelConversion VkSamplerYcbcrModelConversionKHR;

Description

  • VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY specifies that the input values to the conversion are unmodified.

  • VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY specifies no model conversion but the inputs are range expanded as for Y’CBCR.

  • VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709 specifies the color model conversion from Y’CBCR to R’G’B' defined in BT.709 and described in the “BT.709 Y’CBCR conversion” section of the Khronos Data Format Specification.

  • VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601 specifies the color model conversion from Y’CBCR to R’G’B' defined in BT.601 and described in the “BT.601 Y’CBCR conversion” section of the Khronos Data Format Specification.

  • VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020 specifies the color model conversion from Y’CBCR to R’G’B' defined in BT.2020 and described in the “BT.2020 Y’CBCR conversion” section of the Khronos Data Format Specification.

In the VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_* color models, for the input to the sampler Y’CBCR range expansion and model conversion:

  • the Y (Y' luma) channel corresponds to the G channel of an RGB image.

  • the CB (CB or “U” blue color difference) channel corresponds to the B channel of an RGB image.

  • the CR (CR or “V” red color difference) channel corresponds to the R channel of an RGB image.

  • the alpha channel, if present, is not modified by color model conversion.

These rules reflect the mapping of channels after the channel swizzle operation (controlled by VkSamplerYcbcrConversionCreateInfo::components).

Note

For example, an “YUVA” 32-bit format comprising four 8-bit channels can be implemented as VK_FORMAT_R8G8B8A8_UNORM with a component mapping:

  • components.a = VK_COMPONENT_SWIZZLE_IDENTITY

  • components.r = VK_COMPONENT_SWIZZLE_B

  • components.g = VK_COMPONENT_SWIZZLE_R

  • components.b = VK_COMPONENT_SWIZZLE_G

See Also

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 (c) 2014-2019 Khronos Group. This work is licensed under a Creative Commons Attribution 4.0 International License.