Khronos Data Format Specification

Andrew Garrard

Copyright (C) 2015 The Khronos Group Inc. All Rights Reserved.

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Contributors:

Frank Brill
Sean Ellis
Andrew Garrard (editor)
Jonas Gustavsson
Chris Hebert
Daniel Koch
Thierry Lepley
Tommaso Maestri
Kathleen Mattson
Hans-Peter Nilsson
Alon Or-bach
Erik Rainey
Daniel Rakos
Graham Sellers
David Sena

Revision History
Revision 1.0 rev 4July 10, 2015AG
Revision History
Revision 0.1Jan 2015AG
Initial sharing.
Revision 0.2Feb 2015AG
Added clarification, tables, examples.
Revision 0.3Feb 2015AG
Further cleanup.
Revision 0.4Apr 2015AG
Channel ordering standardised.
Revision 0.5Apr 2015AG
Typos and clarification.
Revision 1.0May 2015AG
Submission for 1.0 release
Revision 1.0 rev 2June 2015AG
Clarifications for 1.0 release
Revision 1.0 rev 3July 2015AG
Added KHR_DF_SAMPLE_DATATYPE_LINEAR
Revision 1.0 rev 4July 2015AG
Clarified KHR_DF_SAMPLE_DATATYPE_LINEAR

Table of Contents

1. Introduction
2. Overview
3. Required concepts not contained in this format
4. Translation to API-specific data format representations
5. Data format descriptor
6. Descriptor block
7. Khronos Basic Data Format Descriptor Block
7.1. vendor_id
7.2. descriptor_type
7.3. version_number
7.4. descriptor_block_size
7.5. color_model
7.6. color_primaries
7.7. transfer_function
7.8. flags
7.9. texel_block_dimensions_[0..3]
7.10. bytes_plane_[0..7]
7.11. Sample information
8. Extension for more complex formats
9. Frequently Asked Questions
9.1. Why have a binary format rather than a human-readable one?
9.2. Why not use an existing representation such as those on FourCC.org?
9.3. Why have a descriptive format?
9.4. Why describe this standard within Khronos?
9.5. Why should I use this format if I don’t need most of the fields?
9.6. Why not expand each field out to be integer for ease of decoding?
9.7. Can this descriptor be used for text content?
10. External references
10.1. Adaptive Scalable Texture Compression
10.2. ITU-T BT.601 specification for digital television
10.3. ITU-T BT.709 specification for HDTV
10.4. ITU-T BT.2020 specification for UHDTV
10.5. CIE 1931 XYZ tristimulus values
10.6. Academy Color Encoding System
10.7. sRGB specification
11. Example format descriptors

Abstract

This document describes a data format specification for non-opaque (user-visible) representations of user data to be used by, and shared between, Khronos standards. The intent of this specification is to avoid replication of incompatible format descriptions between standards and to provide a definitive mechanism for describing data that avoids excluding useful information that may be ignored by other standards. Other APIs are expected to map internal formats to this standard scheme, allowing formats to be shared and compared.