ICC meta Tag for Monitor Profiles 0.1

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ICC meta Tag for Monitor Profiles (http://www.freedesktop.org/wiki/Specifications/icc_meta_tag_for_monitor_profiles) Specification @ fd.o

DRAFT

Revision History
ICC meta Tag for Monitor Profiles 0.1 2010-12-30 Kai-Uwe Behrmann, Richard Hughes, Max Derhack, Lars Borg, Florian Höch and others initial version


Table of contents

Introduction

The specification provides means to embed monitor informations into ICC profiles.

ICC profile vendors have to maintain different installation procedures to register ICC device profiles on a client machine. This is either fully customised, but only for certain operating systems, or an manual error prone task through the required user interaction. With ICC profiles for monitors containing device informations, it will be easy for colour management systems to identify monitors and use a matching ICC profile without special registration in the system. This allows for easy preselection and implicit configuration. The advantage for vendors are less maintenance costs and better cross platform support in a flexible manner. Users benefit by the implementation of this proposal through a simplified and more robust colour management system. Adding of device informations to ICC profiles can be assisted through according tools.

This proposal defines key/value pairs for storing into a ICC display profiles meta tag. Consequently only colour management and device identification related properties are considered for inclusion. A explicit configuration in a given CMS shall override such implicit mechanisms as defined by this proposal.


Specification

This version is based on the OpenICC Configuration 0.1.

Keys

The following key/value pairs are defined

  • (key: value)
  • EDID_mnft: decoded three byte string from EDID address 8-9
  • EDID_manufacturer: mapping of mnft to a full string - only for displaying
  • EDID_mnft_id: MSB decoded numerical representation of EDID address 8-9
  • EDID_model_id: LSB decoded numerical representation of EDID address 10-11
  • EDID_date: decoded year of production from EDID address 17 and week of production from EDID address 16
  • EDID_red_x:
  • EDID_red_y:
  • EDID_green_x:
  • EDID_green_y:
  • EDID_blue_x:
  • EDID_blue_y:
  • EDID_white_x:
  • EDID_white_y:
  • EDID_gamma:

The EDID_primary_ prefixed keys and EDID_gamma contain floats with decimal point. The values are decoded from EDID address 25-34 (colour primaries) plus address 23 (gamma).

  • EDID_model: decoded string from EDID text section 54 till 125 of typical type 252
  • EDID_serial: decoded string from EDID text section 54 till 125 of typical type 255

Detailed instructions how to decode EDID can be obtained from VESA through the Enhanced Extended Display Identification Data Standard (E-EDID) - Rel. A, 1.0 .


A parser must be prepared to interpret the contained values numerically and not always textual as is preferred.


Example

{
  "org": {
    "freedesktop": {
      "openicc": {
        "device": {
          "monitor": {
            "prefix": "EDID_", 
            "EDID_red_y": "0.339844", 
            "EDID_red_x": "0.639648", 
            "EDID_mnft_id": "7789", 
            "EDID_blue_x": "0.144531", 
            "EDID_manufacturer": "Goldstar Company Ltd", 
            "EDID_green_y": "0.615234", 
            "EDID_green_x": "0.290039", 
            "EDID_white_y": "0.329102", 
            "EDID_white_x": "0.313477", 
            "EDID_date": "2007-T5", 
            "EDID_gamma": "2.2", 
            "manufacturer": "Goldstar Company Ltd", 
            "mnft": "GSM", 
            "EDID_blue_y": "0.0703125", 
            "EDID_mnft": "GSM", 
            "EDID_model": "L203WT", 
            "model": "LG Flatron L203W", 
            "EDID_model_id": "20030"
          }
        }
      }
    }
  }
}


Discussion

A tag to embed the complete EDID data block is defined. But that serves different goals. Namely it is not possible to support a wider range of devices by this approach. To create a generic meta tag, the serial number and possibly production times need to be stripped from the meta tag, if they are considered non relevant in regards of colour rendering. Most monitors series will be well identified by the EDID_model_id and EDID_mnft_id entries. Others might need the colorimetric primaries and gamma if they can switch colour spaces. The "EDID_date", "EDID_mnft_id" and "EDID_model_id" keys might contain value ranges as allowed by the ICC meta tag definition.


References

1. ICC - http://www.color.org/

2. meta tag - http://www.color.org/ICCSpecRevision_25-02-10_dictType.pdf

3. VESA - http://www.vesa.org/

4. EDID - Enhanced Extended Display Identification Data Standard (E-EDID) - Rel. A, 1.0

4.1 http://en.wikipedia.org/wiki/EDID (overview)

5. ISO 8601 - Data elements and interchange formats – Information interchange – Representation of dates and times


Changes

  • DRAFT 1 - initial
  • DRAFT 2 - splitting of colorimetry compound, Richard Hughes, use EDID_ prefix, Max Derhack and Lars Borg, use ISO 8601 for dates, Lars Borg
  • ICC meta Tag for Monitor Profiles - DRAFT 3 (http://lists.freedesktop.org/archives/openicc/2010q4/002293.html) - remove redundant key name parts, synchronise names, Kai-Uwe Behrmann
  • DRAFT 4 - use JSON example
  • DRAFT 5 - correct JSON example, as pointed out by Florian Höch


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