ITU-T Rec. T.800 | ISO/IEC 15444-1 defines a set of lossless and lossy compression methods for coding continuoustone, bi-level, greyscale or colour digital still images. This Recommendation | International Standard provides two independently created software reference implementations of ITU-T Rec. T.800 | ISO/IEC 15444-1, in order to assist implementers of ITU-T Rec. T.800 | ISO/IEC 15444-1 in testing and understanding its content. The reference software is informative only. This Recommendation | International Standard does not define any additional part of the JPEG 2000 image coding system. Each version of the reference software contains source code, which may be compiled to provide the following functionality: — transcoding from selected, widely available image formats into a JPEG 2000 codestream; — transcoding from selected, widely available image formats into the JP2 file format; — selection of a wide range of JPEG 2000 encoding options (as documented in each reference software); — decoding from a JPEG 2000 codestream to a range of selected widely available image formats; — partial processing of a JP2 file to extract a JPEG 2000 codestream for decoding to a range of selected widely available image formats; NOTE — The reference software does not implement a conforming JP2 file reader. See clause 9. — some additional tools to help with evaluation and testing. The reference software is intended for use as a testing and validation tool for other implementations of JPEG 2000, and to help in the understanding of ITU-T Rec. T.800 | ISO/IEC 15444-1. Although components of the reference software may find application in software intended for product development, this was not an objective of the development of this software, and prospective implementors are cautioned against making any estimations of performance or resource usage based on the reference software.