Summary

This Recommendation specifies the technical features of Mixed Raster Content (MRC) imaging format that enables efficient processing, interchange and archiving of raster-oriented pages containing a mixture of multi‑level and bi-level images. This efficiency is realized through segmentation of the image into multiple layers (planes), as determined by image type, and applying image specific encoding, spatial and colour resolution processing.

A rasterized page may contain one or more image types, such as: multi-level continuous-tone or palletized colours (contone) usually associated with naturally occurring images; bi-level detail associated with text and line-art; multi-level colours associated with the text and line-art. This Recommendation makes provisions for processing, interchange, and archiving of these image types in multiple separate layers. Recombining the layers in a prescribed manner regenerates the original image.

This edition of T.44 integrates Amendment 1 (which added a new Annex B which defines provisions for sharing resources across pages, stripes and layers and provisions for using colour tags as a means of representing text colour, that play an essential role in the application of JBIG2 of ITU-T Rec. T.88) with a number of additional modifications to the main body and its annexes that give the definition of the necessary technical specifications to support YCC colour space (as described in ITU-T Rec. T.42). This will allow the YCC colour space to be deployed using almost the same method as that of the LAB colour space.