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Libjpeg
libjpeg is a free library with functions for handling the JPEG image data format. It implements a JPEG codec (encoding and decoding) 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.
JPEG JFIF images are widely used on the Web. The amount of compression can be adjusted to achieve the desired trade-off between file size and visual quality.
The following utility programs are shipped together with libjpeg:
The command-line program jpegtran provides several features for reformatting and recoding the representation of the DCT coefficients, for transformation of actual image data and for discarding auxiliary data in JPEG files, respectively. The transformations regarding the representation of the coefficients comprise:
These transformations are each completely lossless and reversible. The transformations on the image data comprise:
These are lossless and reversible only regarding the image data that is kept. Reencoding with repeated lossy quantisation of the image data (generation loss) does not take place.
The JPEG implementation of the Independent JPEG Group (IJG) was first publicly released on 7 October 1991 and has been considerably developed since that time. The development was initially mainly done by Tom Lane. The open-source implementation of the IJG was one of the major open-source packages and was key to the success of the JPEG standard. Many companies incorporated it into a variety of products such as image editors and web browsers.
For version 5, which was released on September 24, 1994, the whole code base was rewritten. It introduced the utility programs rdjpgcom and wrjpgcom for handling embedded text comments. The version 6 from 2 August 1995 came with support for progressive JPEG and for the first time with the utility program jpegtran. This utility was extended with features to rotate and flip images and grayscale reduction in version 6b.
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Libjpeg AI simulator
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Libjpeg
libjpeg is a free library with functions for handling the JPEG image data format. It implements a JPEG codec (encoding and decoding) 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.
JPEG JFIF images are widely used on the Web. The amount of compression can be adjusted to achieve the desired trade-off between file size and visual quality.
The following utility programs are shipped together with libjpeg:
The command-line program jpegtran provides several features for reformatting and recoding the representation of the DCT coefficients, for transformation of actual image data and for discarding auxiliary data in JPEG files, respectively. The transformations regarding the representation of the coefficients comprise:
These transformations are each completely lossless and reversible. The transformations on the image data comprise:
These are lossless and reversible only regarding the image data that is kept. Reencoding with repeated lossy quantisation of the image data (generation loss) does not take place.
The JPEG implementation of the Independent JPEG Group (IJG) was first publicly released on 7 October 1991 and has been considerably developed since that time. The development was initially mainly done by Tom Lane. The open-source implementation of the IJG was one of the major open-source packages and was key to the success of the JPEG standard. Many companies incorporated it into a variety of products such as image editors and web browsers.
For version 5, which was released on September 24, 1994, the whole code base was rewritten. It introduced the utility programs rdjpgcom and wrjpgcom for handling embedded text comments. The version 6 from 2 August 1995 came with support for progressive JPEG and for the first time with the utility program jpegtran. This utility was extended with features to rotate and flip images and grayscale reduction in version 6b.