Consider for example the libre software LAMMPS, which uses GNU General Public License. The user writes an input file. Then the software performs some calculations based on the instructions in the input file and produces an output file in simple text format. Now I would like to know what determines the license of the output file and who is the copyright holder of it.


2 Answers 2


There is no licence and the copyright belongs to whoever owns the copyright in the input

The outpost file is simply the original file transformed by the program - just like a Zip file is.

  • Thanks. If the author of the input file releases it under GPL or dedicate it to public domain, does it automatically extend to include the output file as well?
    – apadana
    Aug 16, 2019 at 13:29
  • 2
    @apadana, depends on the license. If the input file is GPL, then the output file is GPL, because the GPL requires this. If the input file is in the public domain, then the output file is in the public domain (if the transformation is non-creative) because there's no copyright on the file. If the input file is CC-BY, then the output file can be licensed however the person doing the transformation wants it to be (so long as attribution is preserved).
    – Mark
    Aug 16, 2019 at 23:42

That Depends

If the output is a straightforward transformation of the input, then the copyright belongs to whoever holds the copyright on the input, as Dale M says.

In that case, if the user has licensed the input file under some permissive license, then the output will be under the same license.

But if the program applies random factors, or if there is interactive input from the user during the course of the program, or takes into account environmental factors so that the output is different for different runs of the same input file, the copyright on the output will belong to the user who runs the program. It may also be a derivative work of the input file, and require the permission of whoever holds the copyright on the input. If the input file was licensed under a permissive license tht allows creation of modified version, then such permission has been granted, but the user may need to put the output under a compatible license if the user releases the output at all.

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