XISF File Format - Second Draft Specification

Juan Conejero

PixInsight Staff
Sep 2, 2004
Valencia, Spain
A new version of the XISF specification document (second public draft) is now available online:


(you may need to refresh your browser). The entire PIDoc source code is also available:


I have included many suggestions and ideas received since the first draft document. The main changes are:

- Monolithic XISF units are now self-contained and restricted to a single .xisf file (no external references allowed in a monolithic XISF file).

- Planar and normal pixel storage models are now realizable (new pixelStorage XML attribute of the Image core element).

- Redesigned syntax of external XISF block locations.

- New/improved figures.

- Removed ambiguities between String16 and String8 Metadata properties (each Metadata property has now a unique mandatory data type).

- Hundreds of bug fixes and improvements.

- New layout thanks to the latest version of the PIDoc compiler script.

This document is now much more mature and accurate than the previous version, so it is a much better platform for discussion and collaboration. There are contributions that I am still evaluating (especially a new compression method suggested by Georg Viehoever) and will probably lead to a third version of the draft document in the incoming days.

A big thanks to everybody who are contributing to this project.