GPL License - Is this OK?
I have read the GPL FAQ and done a fair amount of searching, but can't find where this is specifically covered:
Take a non-GPL program, say a music editor for example, that wanted to use a GPL plug-in to encode files into Ogg Vorbis format.
My understanding is that this does not require the main program to be GPL if all of these are true:
- The plug-in is not statically or dynamically linked
- The plug-in works as a stand alone program and is only controlled via command line parameters
- The main program does not package the plug-in as part of a package or install
So far so good? Ok now imagine this:
- The music editor program has a feature called "Encode to Ogg Vorbis"
- When the feature is selected, the program says "Download plug-in to support this feature?"
- If the user says yes, the plug-in is transparently downloaded and run and seems to be a feature of the program, even though it's really standalone with its input and output controlled by the main program.
- On subsequent use, the main program remembers the location of the plug-in and doesn't even need to prompt the user. It now really seems like a feature of the main program.
- The only input to the plug-in are file paths, the only output is the content generated by the plug-in, no internal private data structures are exchanged.
Would this usage require the main program to be GPL?
Any input much appreciated.