Difference between revisions of "XMP"

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[[Category:Developer]]
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{{Filetype
[[Category:Technology]]
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|license_url=Yes
[[Category:metadata]]
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|web_statement=Yes
[[Category:xmp]]
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|more_permissions=Yes
= Creative Commons Metadata and XMP =
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}}
  
<div style="float: right">
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[[Image:Xmp_tagline.png|right]]
[http://www.adobe.com/products/xmp http://creativecommons.org/images/metadata/xmp_tagline.png]
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[http://www.adobe.com/products/xmp XMP] ([http://en.wikipedia.org/wiki/Extensible_Metadata_Platform Extensible Metadata Platform]) facilitates embedding metadata in files using a subset of RDF. Most notably, XMP supports embedding metadata in PDF and many image formats, though it is designed to support nearly any file type.
</div>
 
  
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Creative Commons is recommending XMP as the preferred format for embedded metadata, given its [http://web.archive.org/web/20070426051136/http://labs.adobe.com/technologies/xmptoolkit/#FAQ support for numerous file formats] and the balkanized state of embedded metadata standards. Others are coming to a similar conclusion; Microsoft has announced support for [http://blogs.msdn.com/pix/archive/2006/08/23/715340.aspx XMP in Vista applications] and Jon Udell [http://blog.jonudell.net/2007/02/14/truth-files-microformats-and-xmp/ notes] "There’s also good support in .NET Framework 3.0 for reading and writing XMP metadata."  Note that even when embedded with XMP metadata, Creative Commons recommends a licensed document include a visible copyright notice; [[Marking|format-specific recommendations]] for visible notices are available.
  
[[XMP]] (Extensible Metadata Platform) facilitates embedding metadata in files using a subset of RDF. Most notably XMP supports embedding metadata in PDF and many image formats, though it is designed to support nearly any file type.
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The Creative Commons [http://www.creativecommons.org/license/ licensing process] offers a XMP template which may be used to mark files within XMP-supporting [[XMP help for Adobe applications|Adobe applications (step-by-step how-to document)]]. An [[Adobe_Metadata_Panel|XMP FileInfo panel]] is also available.
  
Creative Commons is considering recommending XMP as the preferred format for embedded metadata, given its [http://labs.adobe.com/technologies/xmptoolkit/#FAQ support for numerous file formats] and the balkanized state of embedded metadata standards. Others are apparently coming to the same conclusion, e.g., Microsoft has announced support for [http://blogs.msdn.com/pix/archive/2006/08/23/715340.aspx XMP in Vista applications] and Jon Udell [http://blog.jonudell.net/2007/02/14/truth-files-microformats-and-xmp/ notes] "There’s also good support in .NET Framework 3.0 for reading and writing XMP metadata."
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== Specifying License Information ==
  
== Implementations ==
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XMP [http://www.adobe.com/devnet/xmp/ defines] a rights management schema (see XMP Specification, p. 42). Creative Commons sets the following properties (example values):
  
The Creative Commons [http://www.creativecommons.org/license/ licensing process] offers a XMP template which may be used to mark files within XMP-supporting [[XMP Help|Adobe applications (step-by-step how-to document)]].
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* '''xmpRights:Marked''' &mdash; ''False'' if Public Domain, ''True'' otherwise.
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* '''xmpRights:WebStatement''' &mdash; ''http://example.com/pdf-metadata.html'' (Replace with URL containing metadata about the XMP-embedded file; this is referred to as the [[WebStatement|Web Statement]].)
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* '''xmpRights:UsageTerms''' &mdash; An optional field describing legal terms of use; Creative Commons recommends that when present this take the form ''This work is licensed to the public under the Creative Commons Attribution-ShareAlike license http://creativecommons.org/licenses/by­sa/2.0/ verify at http://example.com/pdf­metadata.html'' (Replace URL following 'verify at' with URL containing metadata about the XMP-­embedded file; this is typically the URL specified by '''xmpRights:WebStatement'''.)<br />'''''Note''': as of 2011-05 http://www.metadataworkinggroup.org/pdf/mwg_guidance.pdf suggests using '''dc:rights''' and xmpRights:WebStatement; it probably makes sense to populate dc:rights and xmpRights:UsageTerms with identical content.''
  
=== PDF ===
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We also define a Creative Commons schema ''http://creativecommons.org/ns#'' whose common prefix is cc. It currently has the following properties:
  
* LaTeX users may use the [http://www.creativecommons.org/weblog/entry/4270 pdflatex macro].
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* '''license''' &mdash; The license URL; for example, ''http://creativecommons.org/licenses/by-sa/2.0/''.
* [http://enrico.masala.googlepages.com/plm_index.html PdfLicenseManager] is a standalone GUI/command line tool for embedding XMP in PDFs.
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* '''morePermissions''' &mdash; A URL where additional permissions (commercial licensing, etc) are available.
** PdfLicenseManager uses the [http://www.lowagie.com/iText/ iText] java library, which may be easily incorporated into any Java tool that needs to do XMP embedding.
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* '''attributionURL''' &mdash; The URL to use when attributing this work.
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* '''attributionName''' &mdash; The creator's preferred name to use when attributing this work.
  
=== JPEG ===
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== Verification Links and XMP ==
  
* We have a PHP tool/library for embedding XMP in JPEGs, useful in, e.g., web gallery programs.  See the xmp/php-jpeg module in the [[Source Repository Information|cctools sourceforge subversion repository]].
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A publisher can boost confidence in embedded metadata by providing a '''verifying web statement'''.  A verifying web statement is a [http://watersoftenerreviewspro.com/water-softener-comparison/ URL] which contains metadata with assertions matching those embedded in the file.  The difference is that instead of making the assertions about a URL, the assertions are made in reference to the SHA-1 hash of the file.
  
=== Video (various) ===
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For example, the example web statement <code>http://example.com/pdf-metadata.html</code> would include metadata encoded as [[RDFa]].
  
* None yet
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<code><pre>
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  <p>The document example.pdf is licensed under a
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    <a about="urn:sha1:MSMBC5VEUDLTC26UT5W7GZBAKZHCY2MD" rel="license"
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        href="http://creativecommons.org/license/by/3.0/">
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          Creative Commons Attribution 3.0</a> license.
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    </a>
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  </p>
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</pre></code>
  
=== Other Open Source Implementations ===
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When processing a file containing an embedded web statement, an [http://www.windows8softwares.com application] can retrieve the statement and parse it for additional metadata.  If matching assertions are found which apply to the calculated SHA-1 hash of the file, the application can display an indicator noting increased confidence in the metadata.  This approach has the added benefit of taking advantage of an existing mechanism (copyright take-down procedures) in order to break the confidence in the case of inappropriately licensed material.
  
* [http://grigio.org/xmp_manager XMP Manager] A Ruby action for Nautilus which exposes and allows editing of XMP metadata.
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== Additional Information ==
* [http://librdf.org/raptor/ Raptor] - Supposedly this can generate XMP somewhat, and can also parse it, if you grab the rdf/xml out of the <?xmp...> blocks for it. It's GPL / LGPL / Apache2 licensed so compatible with your code.
 
* [http://www.figuiere.net/hub/blog/?Exempi Exempi] - Hubert Figuiere's lgpl library to handle XMP, mainly for purposes of photo, but generalized.
 
  
== Note on Visible Copyright Notice in PDFs ==
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* [[XMP Implementations]]
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* [[:Category:XMP|All XMP-related articles]]
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* [http://en.wikipedia.org/wiki/Extensible_Metadata_Platform Wikipedia article]
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* [[Adobe Metadata Panel|Adobe XMP FileInfo Panel]]
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* [[XMP help for Adobe applications|XMP help for Adobe applications]]
  
Even when embedded with XMP metadata a licensed PDF document should include a visible copyright notice as described in [[HOWTO Tag HTML pages]].
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<small>The XMP logo is either a registered trademark or trademark of the Adobe Systems Incorporated in the United States and/or other countries.</small>
  
== Note on embedded metadata ==
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{{Translations
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| articles = Pt:XMP
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}}
  
This specification conforms with the [[Nonweb Tagging]] recommendation.
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[[Category:Developer]]
 
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[[Category:Technology]]
== Specification ==
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[[Category:Metadata]]
 
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[[Category:XMP]]
XMP [http://partners.adobe.com/asn/tech/xmp/download.jsp defines] a rights management schema (see section 4.2.5). Creative Commons sets the following properties (example values):
 
 
 
'''xapRights:Copyright''' &mdash; ''This work is licensed to the public under the Creative Commons Attribution-ShareAlike license http://creativecommons.org/licenses/by-sa/2.0/ verify at http://example.com/pdf-metadata.html'' (Replace URL following 'verify at' with URL containing metadata about the XMP-embedded file.)
 
 
 
'''xapRights:Marked''' &mdash; ''False'' if Public Domain, ''True'' otherwise.
 
 
 
'''xapRights:WebStatement''' &mdash; ''http://example.com/pdf-metadata.html'' (Replace with URL containing metadata about the XMP-embedded file.)
 
 
 
We also set cc:license to maintain a direct reference to the license URL.
 
 
 
'''cc:license''' &mdash; ''http://creativecommons.org/licenses/by-sa/2.0/'' (Replace with relevant license URL.)
 
 
 
== Developer Challenges ==
 
 
 
We have setup some [[XMP developer challenges]] to encourage the use of XMP and also to do some research as to what is already supported and what we support.
 
 
 
== XMP Logo ==
 
<small>The XMP logo is either a registered trademark or tradmark of the Adobe Systems Incorporated in the United States and/or other countries.</small>
 

Latest revision as of 05:58, 15 January 2015

File Type Information
Supports embedding license URL: supports_license_url::Yes
Supports embedding web statement: supports_web_statement::Yes
Supports embedding more permissions: supports_more_permissions::Yes
Metadata Location: [[Metadata location::{{{metadata_location}}}]] | (unknown) }}
Metadata Format: [[Metadata format::{{{metadata_format}}}]] | (unknown) }}


Xmp tagline.png

XMP (Extensible Metadata Platform) facilitates embedding metadata in files using a subset of RDF. Most notably, XMP supports embedding metadata in PDF and many image formats, though it is designed to support nearly any file type.

Creative Commons is recommending XMP as the preferred format for embedded metadata, given its support for numerous file formats and the balkanized state of embedded metadata standards. Others are coming to a similar conclusion; Microsoft has announced support for XMP in Vista applications and Jon Udell notes "There’s also good support in .NET Framework 3.0 for reading and writing XMP metadata." Note that even when embedded with XMP metadata, Creative Commons recommends a licensed document include a visible copyright notice; format-specific recommendations for visible notices are available.

The Creative Commons licensing process offers a XMP template which may be used to mark files within XMP-supporting Adobe applications (step-by-step how-to document). An XMP FileInfo panel is also available.

Specifying License Information

XMP defines a rights management schema (see XMP Specification, p. 42). Creative Commons sets the following properties (example values):

  • xmpRights:MarkedFalse if Public Domain, True otherwise.
  • xmpRights:WebStatementhttp://example.com/pdf-metadata.html (Replace with URL containing metadata about the XMP-embedded file; this is referred to as the Web Statement.)
  • xmpRights:UsageTerms — An optional field describing legal terms of use; Creative Commons recommends that when present this take the form This work is licensed to the public under the Creative Commons Attribution-ShareAlike license http://creativecommons.org/licenses/by­sa/2.0/ verify at http://example.com/pdf­metadata.html (Replace URL following 'verify at' with URL containing metadata about the XMP-­embedded file; this is typically the URL specified by xmpRights:WebStatement.)
    Note: as of 2011-05 http://www.metadataworkinggroup.org/pdf/mwg_guidance.pdf suggests using dc:rights and xmpRights:WebStatement; it probably makes sense to populate dc:rights and xmpRights:UsageTerms with identical content.

We also define a Creative Commons schema http://creativecommons.org/ns# whose common prefix is cc. It currently has the following properties:

  • license — The license URL; for example, http://creativecommons.org/licenses/by-sa/2.0/.
  • morePermissions — A URL where additional permissions (commercial licensing, etc) are available.
  • attributionURL — The URL to use when attributing this work.
  • attributionName — The creator's preferred name to use when attributing this work.

Verification Links and XMP

A publisher can boost confidence in embedded metadata by providing a verifying web statement. A verifying web statement is a URL which contains metadata with assertions matching those embedded in the file. The difference is that instead of making the assertions about a URL, the assertions are made in reference to the SHA-1 hash of the file.

For example, the example web statement http://example.com/pdf-metadata.html would include metadata encoded as RDFa.


  <p>The document example.pdf is licensed under a 
     <a about="urn:sha1:MSMBC5VEUDLTC26UT5W7GZBAKZHCY2MD" rel="license" 
        href="http://creativecommons.org/license/by/3.0/">
          Creative Commons Attribution 3.0</a> license.
     </a>
  </p>

When processing a file containing an embedded web statement, an application can retrieve the statement and parse it for additional metadata. If matching assertions are found which apply to the calculated SHA-1 hash of the file, the application can display an indicator noting increased confidence in the metadata. This approach has the added benefit of taking advantage of an existing mechanism (copyright take-down procedures) in order to break the confidence in the case of inappropriately licensed material.

Additional Information

The XMP logo is either a registered trademark or trademark of the Adobe Systems Incorporated in the United States and/or other countries.