The most significant change in v3.3 is the introduction of a completely new set of client-server objects.
- The new objects implement our proposal for the JPIP (JPeg2000 Internet Protocols) standardization effort, in a form which is compatible with the most recent working draft produced by ISO/IEC JTC1/SC29/WG1's JPIP standardization effort, destined to become Part 9 of the JPEG2000 family of standards. The new protocol shares many elements in common with the original JPIK protocol implemented by the earlier client-server files, but there are a large number of important differences. Most significantly, the new protocol supports pure HTTP transport, as well as a more efficient TCP variant, together with more flexible cache management.
- The new client-server implementation offers file-based caching of data received by a client in a previous interactive session, as well as both session-oriented and session-less communications. The server implementation now also includes a rate-distortion optimization element which takes information generated during compression, together with the client's window of interest, and uses this information to sequence information in an order which will increase the quality of the received image, within the window of interest, as fast as possible. Preliminary experiments indicate that the R-D optimal sequencing algorithm improves image PSNR by up to 8dB, when compared to the non-optimal sequencing employed by the earlier "kdu_server" implementation, after receiving the same amount of data.
All known bugs have been fixed (we have a very large user-base now to report bugs).