View source for JPEG 2000 codestream

{{FormatInfo
|formattype=electronic
|subcat=Graphics
|subcat2=JPEG 2000
|extensions={{ext|j2k}}, {{ext|j2c}}, {{ext|jpc}}
|locfdd={{LoCFDD|fdd000138}}, others
}}
'''JPEG 2000 codestream''' (also known as '''J2K''', '''J2C''', or '''JPEG 2000 Part 1, Core Coding System''') is the [[Wavelet compression|wavelet-based]] compressed image format defined in Part 1 of the [[JPEG 2000]] standard. Both lossy and lossless compression are supported.

It may appear in a file by itself, but it was designed to be embedded in [[JP2]] or another file format.

== Format ==
A JPEG 2000 codestream uses a variant of [[JPEG]] format, with a nearly identical system of markers and segments. (Note that the container formats used by JP2 and other JPEG 2000 file formats are completely different.)

== Identifiers ==
There is no official filename extension, but '''.j2k''' and '''.j2c''' are commonly used.

{| class="wikitable"
! Format
! LoCFDD
|-
|Core Coding System || {{LoCFDD|fdd000138}}
|-
|Core Coding, Lossless Compression || {{LoCFDD|fdd000139}}
|-
|Core Coding, Lossy Compression || {{LoCFDD|fdd000140}}
|-
|Core Coding, Profile 0 || {{LoCFDD|fdd000194}}
|-
|Core Coding, Profile 1 || {{LoCFDD|fdd000196}}
|-
|Core Coding, Profile 3 || {{LoCFDD|fdd000211}}
|-
|Core Coding, Profile 4 || {{LoCFDD|fdd000213}}
|-
|Core Coding, BIIF Profile || {{LoCFDD|fdd000170}}
|-
|Core Coding, NDNP Profile || {{LoCFDD|fdd000192}}
|}

== Identification ==
Files start with bytes <code>FF 4F FF 51</code>.

== Specifications ==
* [http://old.jpeg.org/jpeg2000/CDs15444.html JPEG 2000 Committee Drafts] → [http://old.jpeg.org/public/fcd15444-1.pdf fcd15444-1.pdf]
* [http://www.itu.int/rec/T-REC-T.800/en ITU-T Rec.T.800]: JPEG 2000: Core coding system (not free to download)
* [http://www.iso.org/iso/home/store/catalogue_ics/catalogue_detail_ics.htm?csnumber=37674 ISO/IEC 15444-1] (not free to download)
* [http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=41719 ISO/IEC 15444-1:2004/Amd 1:2006]: Profiles for digital cinema applications (not free to download)
* [http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=52174 ISO/IEC 15444-1:2004/Amd 2:2009]: Extended profiles for cinema and video production and archival applications (not free to download)
* [http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=53333 ISO/IEC 15444-1:2004/Amd 3:2010]: Profiles for broadcast applications (not free to download)
* [http://www.gwg.nga.mil/ntb/baseline/docs/bpj2k01/ISOJ2K_profile.pdf BIIF Profile for JPEG 2000]
* [http://www.loc.gov/ndnp/guidelines/docs/NDNP_JP2HistNewsProfile.pdf JPEG 2000 Profile for the National Digital Newspaper Program] (NDNP Profile)

== Sample files ==
* http://www.openjpeg.org/index.php?menu=samples
* http://www.opf-labs.org/format-corpus/jp2k-formats/balloon.j2c

== Software ==
* Refer to [[JPEG 2000#Software]]

== Links ==
* [[Wikipedia:JPEG 2000]]
* [http://www.jpeg.org/jpeg2000/ JPEG 2000 web site]
* [http://www.jpeg.org/jpeg2000/j2kpart1.html JPEG 2000 Part 1 web site]

[[Category:Compression]]
[[Category:JPEG]]
[[Category:JPEG (organization)]]