On 07/06/15 14:19, Bálint Réczey wrote:
The question now is how we should interpret DFSG with regard to Live
DVD-s. Should we stop packaging Libav (and later FFmpeg) in the
current scheme because it allows preinstalling hedgewars (GPLv2 only)
with libavcodec-extra-56 making the DVD violating the license of the
packages or let this be a concern for Live DVD creators?
The thing that is not allowed is either distributing a derivative work
of hedgewars source code with additional restrictions beyond those of
the GPL-2, or distributing a derivative work of libav source code with
additional restrictions beyond those of either GPL-2 or GPL-3.
The hedgewars binary is clearly a derivative work of hedgewars source
and, if you believe the FSF's assertions about dynamic linking, libav
source (via the libavcodec56 GPL-2+ binaries, to which it links).
I find it hard to justify how the hedgewars binary could possibly be a
derivative work of libavcodec-extra-56, given that libavcodec-extra-56
was not involved anywhere in the preparation of the hedgewars binary,
which (presumably) only uses published interfaces from libavcodec56.
Those interfaces happen to be compatible with those found in
libavcodec-extra-56.