Developer(s) | Aaron Boxer |
---|---|
Initial release | January 1, 2016 |
Stable release | 13.0.1 / October 19, 2024 [1] |
Repository | |
Written in | C++ |
Operating system | macOS, Windows, POSIX |
Platform | x86-64, AArch64 |
Predecessor | libopenjp2 |
Available in | English |
Type | Graphics software |
License | AGPL v3 |
Website | github |
Grok is a computer software library to encode and decode images in the JPEG 2000 format. 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.
Grok was forked from OpenJPEG's libopenjp2 in April 2016 by Aaron Boxer under a more restrictive license. [2] He was aiming to close up to the performance of the much more efficient proprietary Kakadu. [3] [4] It fully implements the ISO/IEC 15444-1 technical standard. As of 2022, the newer, complexity-reduced High-Throughput JPEG 2000 standard (HTJ2K, ISO/IEC 15444-15, ITU-T T.814) is being implemented, with decoding support already available. [5]
Grok has been integrated into a number of other open source projects, including:
JPEG is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality. Since its introduction in 1992, JPEG has been the most widely used image compression standard in the world, and the most widely used digital image format, with several billion JPEG images produced every day as of 2015.
JPEG 2000 (JP2) is an image compression standard and coding system. It was developed from 1997 to 2000 by a Joint Photographic Experts Group committee chaired by Touradj Ebrahimi, with the intention of superseding their original JPEG standard, which is based on a discrete cosine transform (DCT), with a newly designed, wavelet-based method. The standardized filename extension is .jp2 for ISO/IEC 15444-1 conforming files and .jpx for the extended part-2 specifications, published as ISO/IEC 15444-2. The registered MIME types are defined in RFC 3745. For ISO/IEC 15444-1 it is image/jp2.
The JPEG File Interchange Format (JFIF) is an image file format standard published as ITU-T Recommendation T.871 and ISO/IEC 10918-5. It defines supplementary specifications for the container format that contains the image data encoded with the JPEG algorithm. The base specifications for a JPEG container format are defined in Annex B of the JPEG standard, known as JPEG Interchange Format (JIF). JFIF builds over JIF to solve some of JIF's limitations, including unnecessary complexity, component sample registration, resolution, aspect ratio, and color space. Because JFIF is not the original JPG standard, one might expect another MIME type. However, it is still registered as "image/jpeg".
The Joint Photographic Experts Group (JPEG) is the joint committee between ISO/IEC JTC 1/SC 29 and ITU-T Study Group 16 that created and maintains the JPEG, JPEG 2000, JPEG XR, JPEG XT, JPEG XS, JPEG XL, and related digital image standards. It also has the responsibility for maintenance of the JBIG and JBIG2 standards that were developed by the former Joint Bi-level Image Experts Group.
ICER is a wavelet-based image compression file format used by the NASA Mars rovers. ICER has both lossy and lossless compression modes.
libjpeg is a free library with functions for handling the JPEG image data format. It implements a JPEG codec alongside various utilities for handling JPEG data. It is written in C and distributed as free software together with its source code under the terms of a custom permissive (BSD-like) free software license, which demands attribution. The original variant is maintained and published by the Independent JPEG Group (IJG). Meanwhile, there are several forks with additional features.
JasPer is a computer software project to create a reference implementation of the codec specified in the JPEG-2000 Part-1 standard - started in 1997 at Image Power Inc. and at the University of British Columbia. It consists of a C library and some sample applications useful for testing the codec.
Lossless JPEG is a 1993 addition to JPEG standard by the Joint Photographic Experts Group to enable lossless compression. However, the term may also be used to refer to all lossless compression schemes developed by the group, including JPEG 2000, JPEG-LS, and JPEG XL.
JPIP is a compression streamlining protocol that works with JPEG 2000 to produce an image using the least bandwidth required. It can be very useful for medical and environmental awareness purposes, among others, and many implementations of it are currently being produced, including the HiRISE camera's pictures, among others.
JPEG XR is an image compression standard for continuous tone photographic images, based on the HD Photo specifications that Microsoft originally developed and patented. It supports both lossy and lossless compression, and is the preferred image format for Ecma-388 Open XML Paper Specification documents.
High Efficiency Video Coding (HEVC), also known as H.265 and MPEG-H Part 2, is a video compression standard designed as part of the MPEG-H project as a successor to the widely used Advanced Video Coding. In comparison to AVC, HEVC offers from 25% to 50% better data compression at the same level of video quality, or substantially improved video quality at the same bit rate. It supports resolutions up to 8192×4320, including 8K UHD, and unlike the primarily 8-bit AVC, HEVC's higher fidelity Main 10 profile has been incorporated into nearly all supporting hardware.
The ISO base media file format (ISOBMFF) is a container file format that defines a general structure for files that contain time-based multimedia data such as video and audio. It is standardized in ISO/IEC 14496-12, a.k.a. MPEG-4 Part 12, and was formerly also published as ISO/IEC 15444-12, a.k.a. JPEG 2000 Part 12.
Kakadu is a closed-source library to encode and decode JPEG 2000 images. It implements the ISO/IEC 15444-1 standard fully in part 1, and partly in parts 2–3. Kakadu is a trademark of NewSouth Innovations Ltd.
Motion JPEG 2000 is a file format for motion sequences of JPEG 2000 images and associated audio, based on the MP4 and QuickTime format. Filename extensions for Motion JPEG 2000 video files are .mj2 and .mjp2, as defined in RFC 3745.
High Efficiency Image File Format (HEIF) is a digital container for storing individual digital images and image sequences. The standard covers multimedia files that can also include other media streams, such as timed text, audio and video.
JPEG XT is an image compression standard which specifies backward-compatible extensions of the base JPEG standard.
JPEG XL is a royalty-free raster-graphics file format that supports both lossy and lossless compression. It is designed to outperform existing raster formats and thus become their universal replacement.
JPEG XS is an interoperable, visually lossless, low-latency and lightweight image and video coding system used in professional applications. Target applications of the standard include streaming high-quality content for pro-AV, virtual reality, drones, autonomous vehicles using cameras, gaming, and broadcasting. Although not official, the XS acronym was chosen to highlight the eXtra Small and eXtra Speed characteristics of the codec.
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