ITU-T Recommendations

The objective of this amendment is to extend the ITU-T Rec. T.88 | ISO/IEC 14492 ('JBIG2') standard for compression of bi-level images, currently specified in terms of compliant data streams and decoding, to also cover compliant encoding. In particular, this amendment: 1) specifies a compliant architecture for JBIG2 encoding; and 2) illustrates example encoding methods for each optional architecture component. Specification of the compliant architecture facilitates applications needing the benefits of a combined encoding/decoding standard, while still permitting competition in the encoding method chosen for any component. The compliant encoding method(s) chosen as examples for each architectural component were selected to target expired (or expiring) patents, openly published methods or royalty-free patents.Selection of a representative method for each optional component should result in reasonable encoder performance in both compression and quality. Using the full combination of components, together with their example encoding methods, provides new users with a default encoder design and a benchmark for JBIG2 encoding that illustrates reasonable near-lossless quality for documents with 300 dpi, or higher, resolution.