This document describes versions 2 and 3 of the SFT (Short Fourier Transform) data format. (Version 1 of the format was never formally described.) Differences between the versions are denoted with the text (Version 2) and (Version 3) respectively. Version 3 is backward compatible with version 2.
This document also describes conventions for naming SFT files and organizing them into directories. The conventions are optional, but encouraged for interoperability with other tools, and particularly for SFT files which are published and distributed across LSC clusters. The filename convention is backward compatible with previous conventions, except that the character "#" is no longer allowed, and the characters "_" and "+" are reserved for delimiting fields in the filename.