Lossless JPEG (original)
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:''See [[Lossless JPEG]] for other uses of the term.'' | :''See [[Lossless JPEG]] for other uses of the term.'' | ||
| − | The original '''lossless JPEG''' (sometimes called '''lossless JPEG-1''') refers to the original [[JPEG]] format when used with lossless compression, instead of the usual lossy compression. It is a standard type of JPEG file, defined in the original JPEG standard (ITU-T Rec. T.81). | + | The original '''lossless JPEG''' (sometimes called '''lossless JPEG-1''') refers to the original [[JPEG]] format when used with lossless compression, instead of the usual lossy compression. It is a standard type of JPEG file, defined in the original JPEG standard (ITU-T Rec. T.81). Though few applications support it, it has found some use in the medical industry (see [[DICOM]]), and in some [[Cameras and Digital Image Sensors|raw camera formats]]. Note that this format is distinct from [[JPEG-LS]]. |
| − | A lossless JPEG image may have any bit depth from 2 to 16 bits per sample. | + | A lossless JPEG image may have any bit depth from 2 to 16 bits per sample. The compression scheme uses [[Huffman coding]] or [[arithmetic coding]]. |
== Identification == | == Identification == | ||
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* [ftp://ftp.graphicsmagick.org/pub/GraphicsMagick/delegates/ljpeg-6b.tar.gz ljpeg-6b.tar.gz]: Lossless JPEG patch for [http://www.ijg.org/files/jpegsrc.v6b.tar.gz IJG libjpeg 6b] (presumably by Ken Murchison) | * [ftp://ftp.graphicsmagick.org/pub/GraphicsMagick/delegates/ljpeg-6b.tar.gz ljpeg-6b.tar.gz]: Lossless JPEG patch for [http://www.ijg.org/files/jpegsrc.v6b.tar.gz IJG libjpeg 6b] (presumably by Ken Murchison) | ||
* [ftp://ftp.cs.cornell.edu/pub/multimed/ljpg.tar.Z Lossless JPEG Codec (Cornell University)]: pnmtoljpg, ljpgtopnm | * [ftp://ftp.cs.cornell.edu/pub/multimed/ljpg.tar.Z Lossless JPEG Codec (Cornell University)]: pnmtoljpg, ljpgtopnm | ||
| + | * [http://www.dclunie.com/jpegge.html Stanford PVRG JPEG] | ||
| + | ** [http://www.cs.unibo.it/~roffilli/pub/JPEGv1.2.1_LINUXport.tgz Linux port] by [http://www.cs.unibo.it/~roffilli/sw.html Matteo Roffilli] | ||
| + | * [http://www.cybercom.net/~dcoffin/dcraw/ dcraw] includes a (probably incomplete) Lossless JPEG decoder | ||
== Sample files == | == Sample files == | ||
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[[Category:JPEG]] | [[Category:JPEG]] | ||
| + | [[Category:JPEG (organization)]] | ||
Latest revision as of 17:41, 16 October 2019
- See Lossless JPEG for other uses of the term.
The original lossless JPEG (sometimes called lossless JPEG-1) refers to the original JPEG format when used with lossless compression, instead of the usual lossy compression. It is a standard type of JPEG file, defined in the original JPEG standard (ITU-T Rec. T.81). Though few applications support it, it has found some use in the medical industry (see DICOM), and in some raw camera formats. Note that this format is distinct from JPEG-LS.
A lossless JPEG image may have any bit depth from 2 to 16 bits per sample. The compression scheme uses Huffman coding or arithmetic coding.
Contents |
[edit] Identification
A lossless JPEG file is identified by the presence of an SOF3, SOF7, SOF11, or SOF15 segment. Refer to JPEG for a discussion of JPEG segments.
[edit] Specifications
- ITU-T Rec. T.81: The JPEG standard
[edit] Software
- Thomas Richter's libjpeg
- ljpeg-6b.tar.gz: Lossless JPEG patch for IJG libjpeg 6b (presumably by Ken Murchison)
- Lossless JPEG Codec (Cornell University): pnmtoljpg, ljpgtopnm
- Stanford PVRG JPEG
- dcraw includes a (probably incomplete) Lossless JPEG decoder
[edit] Sample files
- ljpeg-6b.tar.gz → testimgl.jpg
- ljpg.tar.Z → F-18.ljpg
