JPEG 2000 codestream

Readable

image

JPEG 2000 codestream (also known as J2K, J2C, or JPEG 2000 Part 1, Core Coding System) is the wavelet based compressed image format defined in Part 1 of the JPEG 2000 standard. Both lossy and lossless compression as supported. A JPEG 2000 codestream uses a variant of the JPEG format, with a nearly identical system of markers and segments.

Identify it

Extensions	`.j2k.j2c.jpc`
MIME types	`image/jp2image/x-jp2-codestream`
Signatures	`ff4fff51` at byte 0 (JPEG 2000 Codestream)
PRONOM	`fmt/1794`
Wikidata	`Q105858692`
Library of Congress	`fdd000138fdd000139fdd000140fdd000194fdd000196fdd000211fdd000213fdd000170fdd000192`

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Open it

ImageMagickOpen sourcereads and writes · ImageMagick License
OpenJPEGOpen sourcewrites · 2-clause BSD License
AbydosOpen sourcereads · GNU Lesser General Public License
OpenJUMPOpen sourcereads · GNU General Public License, version 2.0
ConverseenOpen sourcereads · GNU General Public License, version 3.0
ExifToolOpen sourcereads · Artistic License / GNU General Public License, version 1.0 or later
nomacsOpen sourcereads · GNU General Public License, version 3.0
OpenImageIOOpen sourcereads · BSD licenses
PaintShop Photo Pro X3reads and writes
Q122522973reads and writes
Zoner Photo Studioreads and writes
Adobe Photoshop Elements 3.0reads and writes
Grokreads and writes
IrfanViewreads and writes · freeware
PaintShop Pro X4reads and writes
Q1936840writes
Q650922writes · freeware / proprietary license
MediaRich Serverreads
PicaJetreads · freeware
VideoStudio X7reads
ACDSeereads · proprietary license
Advanced Guard for Information Securityreads
Affinity Photoreads
ArcGISreads · proprietary license
Pinnacle Studio 17 Ultimatereads
Quick Lookreads

Convert it

To	With	Fidelity	Command and losses
Portable Network Graphics	ImageMagick	Lossless	`convert in.j2c out.png` Pixels kept; some metadata, colour profiles or layers may be dropped.
Tagged Image File Format	ImageMagick	Lossless	`convert in.j2c out.tif` Pixels kept; some metadata, colour profiles or layers may be dropped.
GIF 89a	ImageMagick	Lossy	`convert in.j2c out.gif` Reduced to 256 colours.
JPEG File Interchange Format 1.02	ImageMagick	Lossy	`convert in.j2c out.jpg` Lossy compression.
WebP	ImageMagick	Lossy	`convert in.j2c out.webp` Lossy compression.

Sources

From Just Solve the File Format Problem (File Formats Wiki), PRONOM, Wikidata. Updated 2026-10-24.

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