"Licensed" codecs

[Alan Cox]

> Plugins and addons should not be considered derivitives automatically. 
> If I write a "pluging" for the GIMP, that mimics the functionality of a 
> comercial Photoshop plugin, why woul it be a derivitive of the GIMP? Now 
> If I modified an existin, GPLed, GIMP plugin, that would have to be GPL. 
> If I write a new plugin from scratch, using the defined plugin 
> interface, that should not have to be GPL.

Consult a lawyer. The definition of 'derivative' is complicated to say the least. 
For actual GPL code the GPL itself deliberately takes a "free nor not at all"
approach.