[LAD] GPL and plugins

Paul Davis paul at linuxaudiosystems.com
Mon Jun 21 11:44:25 UTC 2010

On Mon, Jun 21, 2010 at 7:34 AM, Julien 'Lta' BALLET
<elthariel at gmail.com> wrote:
> http://en.wikipedia.org/wiki/GNU_General_Public_License#Linking_and_derived_works

note that none of the discussions cited really covers the case that
matters for plugins. the key distinction is that plugin APIs generally
have a definition that is indepedent of any particular host. there are
exceptions for a few hosts that provide their own plugin API. but in
general, something like VST or LADSPA or AudioUnit or LV2 cannot be
said to be related to any host or plugin in particular.

This means that the host or plugin is undoubtedly a derived work of
the plugin **API**, but its very hard to argue that the host or plugin
is a derived work of the other, at least not when they are distributed
independently and the host shows no reliance of any kind on the
plugin. If you can load a plugin into Ardour and you can load the same
plugin into Logic, its pretty hard to argue that the plugin is a
derived work of Ardour or Logic. The most hosts a plugin can be loaded
into, the more clearly this lack of derivation becomes clear.

On the other hand, if you could only use a particular host if you have
a particular plugin available, and the host is distributed in a way so
as to automatically load that plugin, then I think that even if the
relationship between them is based on a 3rd party plugin API, one
could quite easily argue that the host is a derived work of the
plugin, in the FSF/GPL sense.


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