JPEG 2000's flexibility with respect to random access, codestream reordering and incremental decoding is highly exploitable in a networked environment. Part 9 of JPEG 2000 is being written to define tools for supporting image and metadata delivery in this context. It is currently (January 2004) at the Final Committee Draft stage, and is expected to be completed for publication by the second half of 2004.
The main component of Part 9 is a client-server protocol called JPIP. JPIP may be implemented on top of HTTP, but is designed with a view to other possible transports. To facilitate its deployment in systems with varying degrees of complexity, JPIP handles several different formats for the image data returned by the server: these include ordinary image formats, such as complete JPEG or JPEG 2000 files, and two new types of incremental "stream" that use JPEG 2000's "tiles" and "precincts" to take full advantage of its scalabilty properties. JPIP also supports both stateless and stateful modes of operation, enabling sophisticated cache-modelling to eliminate the redundant transmission of data.
JPIP provides selective access to the image metadata that may be contained within JPEG 2000 files. Although Part 9 is focused on the application of technology from Part 1, including the JP2 file format, it does support some file format extensions from Part 2. A mechanism has also been provided for selection from amongst multiple codestreams in JPX (Part 2), MJ2 (Part 3) and JPM (Part 6) files. Potentially this could be applied to any file format containing images, not just to the JPEG 2000 family of file formats.
Part 9 also defines some new file format boxes for indexing JPEG 2000 files and codestreams. The indexes are based on the same concepts as the JPIP stream types, and may be useful in server implementations of JPIP. They are also intended, however, to enable random access to JPEG 2000 files in the absence of JPIP. For example, the byte-range requests built into an unmodified HTTP (version 1.1) server could be used for this purpose.
Part 9 became an International Standard (ISO/IEC 15444-9) in October 2004.
It is currently available for download from ITU-T as their Recommendation T.808
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