JPEG-LS

File Format
Name	JPEG-LS
Ontology	Electronic File Formats Graphics JPEG-LS
Extension(s)	.jls
LoCFDD	fdd000151
PRONOM	fmt/150
Released	1998

JPEG-LS is an image file format and compressed data format. It supports both lossy and lossless compression. The lossy compression is often called "near-lossless", because the encoder can set a limit on the maximum error. Its compression algorithm is LOCO-I, developed by HP Labs.

Disambiguation

JPEG-LS files are similar in structure to JPEG, but for all practical purposes, JPEG-LS is a separate and incompatible format.

Beware of documents which confuse the term "JPEG-LS" with the term "Lossless JPEG". See Lossless JPEG for more information.

Identification

Like JPEG, JPEG-LS files begin with bytes FF D8 FF.

A JPEG-LS file will contain an 0xF7 ("SOF55" or "JPG7") segment somewhere in it. Often, the 4th byte in the file is 0xF7.

Related formats

JPEG-LS compression can be used in some other file formats, such as JPX, JPM, SPIFF, and DICOM.

Specifications

• ITU-T Rec. T.87

Software

• CharLS: A C++ JPEG-LS library. Includes sample files.
• Thomas Richter's libjpeg
• UBC JPEG-LS Codec
• XnView

External links

• HP Labs LOCO-I/JPEG-LS Home Page
• Wikipedia article