angle/extensions/ANGLE_yuv_internal_format.txt

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Name
ANGLE_yuv_internal_format
Name Strings
GL_ANGLE_yuv_internal_format
Contributors
Mohan Maiya, Samsung
Jamie Madill, Google
Contacts
Mohan Maiya, Samsung (m.maiya 'at' samsung 'dot' com)
Notice
Copyright (c) 2021 The Khronos Group Inc. Copyright terms at
http://www.khronos.org/registry/speccopyright.html
Status
Draft.
Version
Version 5, June 23, 2021
Number
OpenGL ES Extension ###
Dependencies
OpenGL ES 3.0 is required.
Overview
This extension introduces a few sized internal YUV texture formats
that can be used to create immutable textures using the TexStorage2D API.
The only valid texture target supported is TEXTURE_2D, an INVALID_ENUM
error is generated otherwise. There is no mipmap support and only NEAREST
minification and magnification filters are supported.
Support for the extension only requires the support of the commonly used 8-bit
2-plane YUV format listed in the "New Tokens" section, refer to [fn1] for details
about the formats and layout. It is up to the implementation to extend support
for the other YUV formats.
[fn1] : https://www.fourcc.org/yuv.php
New Types
None.
New Procedures and Functions
None.
New Tokens
List of non-standard YUV internal formats
// 8-bit YUV formats
G8_B8R8_2PLANE_420_UNORM_ANGLE 0x96B1
G8_B8_R8_3PLANE_420_UNORM_ANGLE 0x96B2
// 10-bit YUV formats
G10X6_B10X6R10X6_2PLANE_420_UNORM_3PACK16_ANGLE 0x96B3
G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16_ANGLE 0x96B4
// 12-bit YUV formats
G12X4_B12X4R12X4_2PLANE_420_UNORM_3PACK16_ANGLE 0x96B5
G12X4_B12X4_R12X4_3PLANE_420_UNORM_3PACK16_ANGLE 0x96B6
// 16-bit YUV formats
G16_B16R16_2PLANE_420_UNORM_ANGLE 0x96B7
G16_B16_R16_3PLANE_420_UNORM_ANGLE 0x96B8
Issues
1. How was the new format list chosen?
Commonly used planar YUV formats across various platforms were surveyed,
including new platforms that support HDR content. A subset of those were
chosen to be required. It is up to the implementations to extend support
for the rest of the formats.
2. What is the colorspace of image data of a texture created with the new formats?
The texture or sampler parameter APIs can be expanded to indicate the colorspace
in a layered extension and is outside the scope of this extension. The colorspace
for textures with the above YUV formats is assumed to be ITU-R BT.601 with YUV
values in limited range. Refer to ITU-R BT.601 spec for further details.
Revision History
#5 - (June 23, 2021) Mohan Maiya
Renamed format enums from *_ANGLEX to *_ANGLE
#4 - (June 23, 2021) Mohan Maiya
Removed references to GL_OES_EGL_image_external
and restricted the spec to simply introducing new
sized internal YUV formats. Also updated enum values
#3 - (June 8, 2021) Mohan Maiya
Clarification regarding default colorspace
#2 - (May 10, 2021) Mohan Maiya
Update overview section to specify support for
immutable textures
#1 - (April 10, 2021) Mohan Maiya
Original draft