JPX

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|formattype=electronic
 
|formattype=electronic
 
|subcat=Graphics
 
|subcat=Graphics
|extensions={{ext|jpf}},{{ext|jpx}}
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|subcat2=JPEG 2000
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|extensions={{ext|jpf}}, {{ext|jpx}}
 
|mimetypes={{mimetype|image/jpx}}
 
|mimetypes={{mimetype|image/jpx}}
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|locfdd={{LoCFDD|fdd000154}}
 
|pronom={{PRONOM|fmt/151}}
 
|pronom={{PRONOM|fmt/151}}
 
}}
 
}}
'''JPX''' is the wavelet-based compressed image format defined by [http://www.jpeg.org/jpeg2000/j2kpart2.html Part 2] of the [http://www.jpeg.org/jpeg2000/ JPEG 2000 standard]. The format syntax is defined in [http://www.jpeg.org/public/15444-2annexm.pdf ISO/IEC 15444-2:2004 (E) - ITU-T Rec. T.801 (08/2002) - Annex M - JPX extended file format syntax]. Note that the final standards are not freely available, but the [http://www.jpeg.org/jpeg2000/CDs15444.html committee drafts] are. It is an extension to the [[JP2]] format. In addition to the [[JP2]] feature set, [[JPX]] also offers:
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[[JPX]] is a complex and versatile image file format, defined in Part 2 of the [[JPEG 2000]] standard (ISO/IEC 15444-2).
  
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It is an extension of [[JP2]] format. In addition to the JP2 feature set, JPX offers:
 
* Extended colour space support
 
* Extended colour space support
 
* Mechanisms for including opacity information
 
* Mechanisms for including opacity information
 
* Fragmented codestreams (even across multiple files)
 
* Fragmented codestreams (even across multiple files)
 
* The possibility to combine multiple codestreams as composites or animations
 
* The possibility to combine multiple codestreams as composites or animations
* The possibility to have codestreams that use alternative compression methods (uncompresssed, [[Modified Huffman]],[[Modified READ]],[[Modified Modified READ]],[[JBIG]], [[JPEG]],[[JPEG-LS]],[[JBIG2]],[[JBIG]]).
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* The possibility to use compression methods other than [[JPEG 2000 codestream]] ([[wavelet compression]]): uncompressed, [[Modified Huffman]], [[Modified READ]], [[Modified Modified READ]], [[JBIG]], [[JPEG]], [[JPEG-LS]], [[JBIG2]]
  
See also [[Wikipedia:JPEG 2000]].
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The JPX specification is apparently so large and difficult that its creators felt the need to define a simpler subset of it named '''Baseline JPX''', which lies between JP2 and the full JPX format in complexity. Baseline JPX files, for example, can only use wavelet compression.
  
== Specifications ==
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== Identifiers ==
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The current version of the standard clearly states that the official filename extension is '''.jpf''', and doesn't even mention '''.jpx''' as a possibility. However, some reputable sources say that '''.jpx''' is legitimate, or even preferred.
  
* [http://www.jpeg.org/public/15444-2annexm.pdf JPX extended file format syntax]
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== Identification ==
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JPX files begin with bytes <code>00 00 00 0c 6a 50 20 20 0d 0a 87 0a ?? ?? ?? ?? 66 74 79 70 6a 70 78 20</code>.
  
== Sample images ==
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Note that some Adobe applications (most notably [[Adobe Photoshop]]) produce JPX images that erroneously start with the [[JP2]] byte sequence (i.e. the last 4 bytes in the string above are <code>6a 70 32 20</code>). This makes them (superficially) indistinguishable from JP2 images.
  
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== Specifications ==
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* [http://old.jpeg.org/public/15444-2annexm.pdf JPEG 2000 Part 2 (Extensions) Annex M]: JPX extended file format Syntax
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* [http://old.jpeg.org/public/15444-2annexn.pdf JPEG 2000 Part 2 (Extensions) Annex N]: JPX file format extended metadata definition and syntax
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* [http://old.jpeg.org/jpeg2000/CDs15444.html JPEG 2000 Committee Drafts] → [http://old.jpeg.org/public/fcd15444-2.pdf fcd15444-2.pdf]
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* [http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=33160 ISO/IEC 15444-2] (not free to download)
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* [http://www.itu.int/rec/T-REC-T.801/en ITU-T Rec. T.801] (not free to download)
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== Sample files ==
 
* [http://www.opf-labs.org/format-corpus/jp2k-formats/ JPEG 2000 sample images]
 
* [http://www.opf-labs.org/format-corpus/jp2k-formats/ JPEG 2000 sample images]
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== Related formats ==
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* [[GMLJP2]] is a metadata standard that allows one to include geospatial metadata in georeferenced JPX images.
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== Links ==
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* [[Wikipedia:JPEG 2000]]
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== Editors' notes ==
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There must be a story behind why the JPX filename extension is .jpf instead of .jpx, but we have not been able to locate it. Perhaps it was originally intended to be .jpx, but was changed due to a conflict. The next most common use of .jpx seems to be for JBuilder project files.
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[[Category:Video]]
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[[Category:Box file format]]
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[[Category:JPEG (organization)]]

Latest revision as of 17:27, 16 October 2019

File Format
Name JPX
Ontology
Extension(s) .jpf, .jpx
MIME Type(s) image/jpx
LoCFDD fdd000154
PRONOM fmt/151

JPX is a complex and versatile image file format, defined in Part 2 of the JPEG 2000 standard (ISO/IEC 15444-2).

It is an extension of JP2 format. In addition to the JP2 feature set, JPX offers:

The JPX specification is apparently so large and difficult that its creators felt the need to define a simpler subset of it named Baseline JPX, which lies between JP2 and the full JPX format in complexity. Baseline JPX files, for example, can only use wavelet compression.

Contents

[edit] Identifiers

The current version of the standard clearly states that the official filename extension is .jpf, and doesn't even mention .jpx as a possibility. However, some reputable sources say that .jpx is legitimate, or even preferred.

[edit] Identification

JPX files begin with bytes 00 00 00 0c 6a 50 20 20 0d 0a 87 0a ?? ?? ?? ?? 66 74 79 70 6a 70 78 20.

Note that some Adobe applications (most notably Adobe Photoshop) produce JPX images that erroneously start with the JP2 byte sequence (i.e. the last 4 bytes in the string above are 6a 70 32 20). This makes them (superficially) indistinguishable from JP2 images.

[edit] Specifications

[edit] Sample files

[edit] Related formats

  • GMLJP2 is a metadata standard that allows one to include geospatial metadata in georeferenced JPX images.

[edit] Links

[edit] Editors' notes

There must be a story behind why the JPX filename extension is .jpf instead of .jpx, but we have not been able to locate it. Perhaps it was originally intended to be .jpx, but was changed due to a conflict. The next most common use of .jpx seems to be for JBuilder project files.

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