[Openicc] ICC meta Tag for Monitor Profiles - DRAFT 1
ku.b at gmx.de
Tue Nov 30 05:43:45 PST 2010
The Draft provides means to embed monitor informations into ICC profiles.
== Introduction ==
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 maintainance 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.
The following key/value pairs are defined
* (key: value)
* mnft: decoded three byte string from EDID address 8-9
* manufacturer: mapping of mnft to a full string - only for displaying
* mnft_id: MSB decoded numerical representation of EDID address 8-9
* model_id: LSB decoded numerical representation of EDID address 10-11
* week: week of production from EDID address 16
* year: decoded year of production from EDID address 17
containing a comma separated list of floats with decimal
point. The values are decoded from EDID address 25-34 (colour
primaries) plus address 23 (gamma)
* model: decoded string from EDID text section 54 till 125 of
typical type 252
* 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 .
keys value is composed from the according EDID block colorimetry
informations. The values are each written as floating point as permitted
by the ICC meta tag specifications and separated by comma. The order of
the contained values is described by the key name itself. Parser must be
prepared to interpret the contained values numerically and not textual.
The data is a dump of iccDumpProfile from SampleICC
Contents of metaDataTag tag ('meta' = 6D657461)
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 model_id and mnft_id entries. Others might need the
if they can switch colour spaces.
The "week", "year", "mnft_id" and "model_id" keys might contain value
ranges as allowed by the ICC meta tag definition.
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)
developing for colour management
www.behrmann.name + www.oyranos.org
PS: Further discussed could be the EDID CMD block. If someone would pass us a
EDID block containing such data, that would be helpful. Thanks.
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