This will be used by filters which have internal buffers which need to
be flushed at the end, e.g. the "soxr" resampler.

Not used.  Force implementations to initialize out_audio_format.

For easier state management inside filter plugins.

API simplification.  We can now avoid abusing a "size_t*" as
additional return value.

Replaces GLib's GError.

The filter API allows us to implement software volume as a pluggable
filter, and we will be able to integrate libraries like SoX.

This patch allows the output plugins to import only mixer_list.h,
instead of the full mixer_api.h (which would expose internal
structures).

mixer_control.h should provide the functions needed to manipulate a
mixer, without exposing the internal mixer API (which is provided by
mixer_api.h).

This updates the copyright header to all be the same, which is
pretty much an update of where to mail request for a copy of the GPL
and the years of the MPD project. This also puts all committers under
'The Music Player Project' umbrella. These entries should go
individually in the AUTHORS file, for consistancy.

This patch introduces the mixer for the pulse output.

Technically speaking, the pulse index is needed to get or set
the volume. You must define callback fonctions to get this index since
the pulse output in mpd is done using the simpe api. The pulse simple api
does not provide the index of the newly defined output.

So callback fonctions are associated to the pulse context.
The list of all the sink input is then retreived.
Then we select the name of the mpd pulse output and control
its volume by its associated index number.
Signed-off-by: Patrice Linel <patnathanael@gmail.com>
Signed-off-by: David Guibert <david.guibert@gmail.com>

[mk: fixed whitespace errors and broke long lines; removed
daemonization changes from main.c]

Don't include conf.h in mixer_api.h.  Use a forward struct declaration
instead.

The method control() is too complicated, and overengineered.  Replace
it with two trivial functions: get_volume() and set_volume().

The mixer plugins should re-use the mixer struct and incorporate it in
their object class.