ISO/IEC 15444-5:2003 provides two independently created software reference implementations of ISO/IEC 15444-1, in order to assist implementers of ISO/IEC 15444-1 in testing and understanding its content. ISO/IEC 15444-1 defines a set of lossless and lossy compression methods for coding continuous-tone, bi-level, greyscale or colour digital still images.

The reference software is informative only. ISO/IEC 15444-5:2003 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 that the reference software does not implement a conforming JP2 file reader.);
• some additional tools to help with evaluation and testing.