In computer software, Grok is a library to encode and decode images in the JPEG 2000 format. It fully implements Part 1 of the ISO/IEC 15444-1 technical standard. It is designed for stability, high performance, and low memory usage. Grok is free and open-source software released under the GNU Affero General Public License (AGPL) version 3.

Features

1. High performance - grk_decompress is currently over 1/2 the speed of Kakadu, one of the leading commercial JPEG 2000 libraries
2. Fast sub-tile decode
3. Supports decoding to stdout for png, jpeg, bmp, pnm, and raw output formats
4. Supports TLM code stream marker for fast single-tile and sub-tile decoding of large tiled images
5. Supports PLT code stream marker for fast sub-tile decoding of large single-tile images
6. Full support for ICC profiles and other meta-data such as XML, IPTC and XMP
7. Supports new Part 15 of the standard, aka High Throughput JPEG 2000, which promises up to a 10x speed up over the original Part 1 of the JPEG 2000 standard

Integration

Grok has been integrated into a number of other open source projects, including:

1. Cantaloupe image server
2. IIPSrv image server
3. Horos medical image viewer

References

Further reading

• "JPEG2000 Image Compression Fundamentals, Standards and Practice", by David S. Taubman, Michael W. Marcellin. ISBN 0-7923-7519-X
• Johan van der Knijff (2011). "JPEG 2000 for Long-term Preservation: JP2 as a Preservation Format". D-Lib Magazine. 17 (5/6). doi:10.1045/may2011-vanderknijff.
• Johan van der Knijff (2022). "Generating lossy access JP2s from lossless preservation masters". {{cite journal}}: Cite journal requires |journal= (help)

External links

• Official website
• User guide

See also

• OpenJPEG
• Kakadu