What is a .J2K file?
J2K is a raw JPEG 2000 codestream without the JP2 file wrapper.
- Did you know
- J2K holds JPEG 2000 image data without the extra metadata of a full JP2 file.
- JPEG 2000 uses a wavelet transform rather than the discrete cosine transform of ordinary JPEG, offering lossless and lossy coding in one design.
- Raw JPEG 2000 codestreams open with the two-byte start-of-codestream marker FF 4F, which is how decoders tell them apart from boxed JP2 files.
- What Analyser reads
- Decode and preview extra still-image formats in pure JavaScript - Truevision TGA, QOI, Netpbm (PPM/PGM/PBM), PCX, farbfeld, WBMP, XBM/XPM, Sun Raster and SGI are fully rendered - and read header metadata from codec-heavy formats: Radiance HDR, DirectDraw Surface (DDS) game textures, OpenEXR, JPEG 2000, JPEG XR, EPS/PostScript, Windows WMF/EMF metafiles, Apple ICNS icons, CUR/ANI cursors, MNG and Lottie animations.
- Depth of analysis
- .J2K is an identification-grade format: Analyser recognises it from its bytes and decodes the header metadata it carries, rather than opening it in a full viewer. Formats that do get a full viewer are marked "Full" on the formats page.
- Open a .J2K file
- Drag a .J2K file onto the Analyser home page (or tap to pick one). It is identified entirely in your browser - nothing is uploaded, there is no account, and it works offline once installed.