[mythtv] Plugins license

Paul Bender pebender at san.rr.com
Sat Oct 21 18:16:41 UTC 2006

Colin Guthrie wrote:
> Josh Lefler wrote:
>> Ivan, IANAL, but MythTV itself is released under the GPL. Since it isn't
>> possible to use GPLed code in a project that is not GPL. releasing a
>> plugin under another license would at least require reimplementing large
>> parts of MythTV that plugins depend on and at worst be impossible
>> without rewriting MythTV itself.
> While IAANAL, that is not my understanding of the GPL. I thought that
> you it is perfectly OK to *use* GPL'ed code in other projects, provided
> that any *modification* you make to that code are also released under
> the GPL.
> In the case of writing and distributing a plugin, as I understand it at
> least, it would be perfectly OK to use whichever license the user wants
> on that particular bit of code.
> As far as any changed the plugin required in the core mythtv, it is
> unlikely that:
> a) Ivan will *need* to modify mythtv anyway
> b) Ivan would *want* to modify mythtv *without* releasing his changes
> under the GPL.

This is not the case. What you are describing is much more akin to the 
LGPL than the GPL.

If the software is a "derivative work" of software that is licensed 
under the GPL, then the software must be licensed under the GPL. The 
definition of "derivative work" is something that is defined by the 
legal system. However, if the plugin uses MythTV libraries (e.g. libmyth 
and libmythui), then most would agree that your plugin is a derivative 
work of MythTV because it would be useless without the MythTV libraries.

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