JPEG 2000
JPEG 2000 (or JPEG2000) is standard that defines a wavelet-based raster image compression format, and a family of associated file formats, protocols, etc.
For details about specific formats, see:
- JPEG 2000 codestream
- JP2 (base still image format)
- JPX (extended still image format)
- JPM (compound image format)
- MJ2 (motion JPEG 2000)
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Disambiguation
JPEG 2000 is sometimes incorrectly used as a synonym for JP2, and vice versa. Although JP2 might be the most important part of the JPEG 2000 standard, it is only one small part of it.
In some contexts, JPEG 2000 is used to mean the compressed codestream format, instead of the whole standard.
The terms JPEG 2000 and JPEG2000 (with and without a space) seem to be used interchangeably. The parts of the official specification that are freely available use only JPEG 2000, so that is probably the preferred form. But it must have been settled on late in the standardization process: even some of the committee drafts prefer JPEG2000.
Details
The JPEG 2000 standard consists of many parts, including:
- Part 1: Core coding system. Defines JPEG 2000 codestream format and the JP2 file format.
- Part 2: Extensions. Defines JPX.
- Part 3: Motion JPEG 2000 (MJ2)
- Part 6: Compound image file format (JPM)
- Part 8: JPSEC
- Part 9: JPIP
- Part 10: JP3D
- Part 11: JPWL
- Part 12: ISO Base Media File Format
Format
At the highest level, JPEG 2000 files (JP2, JPX, JPM, and MJ2, but not the codestream format) consist of a hierarchical sequence of tagged "boxes". It is the same format used by Quicktime and MPEG-4, but with different terminology.
Identification
Most JPEG 2000-related files (but not the codestream format) begin with bytes 00 00 00 0c 6a 50 20 20 0d 0a 87 0a.
This byte sequence represents a box of type "jP " (JPEG 2000 signature), which contains an arbitrary 4-byte signature (0d 0a 87 0a).
Specifications
See also the articles about the specific file formats. Most of the official JPEG 2000 specification is not freely available, but the committee drafts are. (Exception: Specifications for the high-level parts of the JP2 and JPX formats are freely available.)
- ISO/IEC 15444
- JPEG 2000 Committee Drafts
- ITU-T Rec.T.800: JPEG 2000: Core coding system
- ITU-T Rec.T.801: JPEG 2000: Extensions
- ITU-T Rec.T.802: JPEG 2000: Motion JPEG 2000
- ITU-T Rec.T.803: JPEG 2000: Conformance testing
- ITU-T Rec.T.804: JPEG 2000: Reference software
- ITU-T Rec.T.805: JPEG 2000: Compound image file format
- ITU-T Rec.T.807: JPEG 2000: Secure JPEG 2000
- ITU-T Rec.T.808: JPEG 2000: Interactivity tools, APIs and protocols
- ITU-T Rec.T.809: JPEG 2000: Extensions for three-dimensional data
- ITU-T Rec.T.810: JPEG 2000: Wireless
- ITU-T Rec.T.812: JPEG 2000: An entry level JPEG 2000 encoder
- ITU-T Rec.T.813: JPEG 2000: XML structural representation and reference
- RFC 3745: MIME Type Registrations for JPEG 2000
