2000.03.31 01:10 "Re: jpeg2000 question", by Louis H. Sharpe II
Does anybody know of some repository of jp2 (jpeg2000, to be approved by ISO/ITU-T by the end of this year) and/or a tool to write (some sort of) those images.
To my knowledge, there are no .jp2 file format files available for download, but there are various tools which can generate and encode jpeg2000 codestreams. See:
and click on the link for the new final committee draft.
JPEG 2000 has a codestream syntax based on markers as with the original JPEG. Part I of the standard (now in Final Committee Draft status as of our Tokyo meeting two weeks ago) has an *optional* .jp2 file format which may be wrapped around the codestream. This is functionally equivalent to the JFIF extension to JPEG (i.e., it provides some minimal number of parameters many applications require such as color space and resolution), but it is implemented differently. jp2 is wrapped around the codestream, whereas the JFIF marker is embedded in the codestream. We took this latter approach to allow a family of file formats to be created, the first of which is jp2, but others will include Motion JPEG 2000, a simple animation format (time for a discussion with the MNG folks) and support for layered compound images. As Bill Radcliffe points out, this uses the powerful and flexible syntax from QuickTime which has also been adopted by MPEG4.
TIFF-FX is an implementation of layered, compound images for color facsimile which is defined in RFC 2301 and ISO T.44 A trial implementation of JPEG 2000 in TIFF-FX was created by members of the JPEG 2000 File Format Ad Hoc Group last summer, but neither this nor a simpler JPEG-2000-only proposal has been formally submitted to Adobe for inclusion in the missing-in-action TIFF version 7 draft. It took the Tom Lane TIFF Technical Note #2 approach of fully encapsulating the codestream, without duplicating information in tags.
Much progress was made in Tokyo by the Reference Software Ad Hoc Group toward getting open reference software into the public domain by the time the standard is issued. Everyone acknowledges the significant contribution the IJG code made toward getting the original JPEG widely and properly supported. The people involved in both the Jasper effort in Canada and the JJ2000 Java effort in Europe are working toward providing open reference implementations.
Picture Elements, Inc.