Amendment 5 to ITU-T T.808 | ISO/IEC 15444-9 contains a minor enhancement that provides tools and definitions to enable UDP as transport layer for the JPIP protocol. A UDP packaging of messages into chunks is described, and mechanisms for flow control and to detect and recover from package loss are introduced. The UDP transport is defined in the new Annex K.
Amendment 5 also includes a minor clarification in the definition of the Placeholder Box.
Since Amendment 3 of ITU-T T.801 | ISO/IEC 15444-2 adds the possibility to rotate compositing layers by multiples of 90 degrees and/or to flip them horizontally and vertically, the definition of the view window and context range of ITU-T T.808 | ISO/IEC 15444-9 had to be extended to respect this additional feature.
A further addition allows a JPIP client to identify the request fields a server is prepared to handle. This new request addresses the need of a client to identify the capabilities of the server beforehand, and thus to adapt and optimise its strategy to retrieve data from the server.