Spectrum Viewer can read a lot of files. Text, binary, you name it. Still I felt the need to create yet another proprietary file format. Why? When SV exits, it saves its state (including all loaded data sets) into the LastSession.svf file. When the program is restarted, it loads this file and the program comes back exactly the way you left it. As demands grew, so did the svf format, and finally it is mature enough to make its specs public. You can even use the svf format to store your own data, and not use Spectrum Viewer at all, but use your own programs to read it. In my opinion the format is very versatile. The general specs are:

The exact structure of the SVF file is described below. If you decide to use the format yourself, I have included SVF.h and SVF.c as well so you can get started right away. 

The exact structure of a .svf file is as follows. First, there are the file parameters.

Then, for each data set the following block:

If you're interested to use this format in your own programs, take a look at the SVF.h file and the SVF.c file.

If you are programming to write .svf files, you can debug your files in SV with the svf test mode. Set in the specview.ini file the value of "Show SVF file info when reading" to 1.