pulseaudio/LICENSE

All PulseAudio source files are licensed under the GNU Lesser General Public
License. (see file LGPL for details)

However, the server side has optional GPL dependencies.  These include the
libsamplerate (for core libraries) and bluez (for the bluetooth proximity helper
program) libraries, although others may also be included in the future.  If
PulseAudio is compiled with these optional components, this effectively
downgrades the license of the server part to GPL (see file GPL for details),
exercising section 3 of the LGPL. In such circumstances, you should treat the
client library (libpulse) of PulseAudio as being LGPL licensed and the server
part (libpulsecore) as being GPL licensed. Since the PulseAudio daemon, tests,
various utilities/helpers and the modules link to libpulsecore and/or the
afore mentioned optional GPL dependencies they are of course also GPL licensed
also in this scenario.

Andre Adrian's echo cancellation implementation is licensed under a less
restrictive license - see src/modules/echo-cancel/adrian-license.txt for
details.

Some other files pulled into PA source (i.e. reference implementations that are
considered too small and stable to be considered as an external library) use the
more permissive MIT license. This include the device reservation DBus protocol
and realtime kit implementations.

Additionally, a more permissive Sun license is used for code that performs
u-law, A-law and linear PCM conversions.

While we attempt to provide a summary here, it is the ultimate responsibility of
the packager to ensure the components they use in their build of PulseAudio
meets their license requirements.