The existing buffer implementation has a major flaw: it is unable to
re-fill the buffer until it has been consumed completely, leading to
many occasions where the render callback needs to generate silence,
just because the play() implementation was unable to append more
data.  The fifo_buffer library handles that well.

When adding or updating a song, we get a log message even if debug is not
enabled. It seems odd that removing a song shouldn't be done at the same log
level; otherwise looking at the log leads you to believe songs are never
removed from the library on update.
Signed-off-by: Dan McGee <dan@archlinux.org>

Some compilers are very picky, but we really aren't interested in the
return value.

This might break older versions, I didn't test.

Fixes endless loop when the last line of a text file was not
terminated (bug 3470).

This was disabled when compiled with a new ffmpeg version.  Older
ffmpeg versions used it explicitly, while newer ones may pass it
through from the codec.

This fixes seeking in the vorbis decoder during MPD startup.

This fixes a bug when libsamplerate returns an empty buffer for a very
small input buffer.  The caller thinks this is an error, bug there is
no GError object.

pcm_buffer_get() cannot ever return NULL.

Implements support for libavcodec 0.9, which removes the compatibility
macros SAMPLE_FMT_*

Minor optimisation.

Use the tag_item_names table to look up the names of all MPD tags, and
remove the duplicate entries from ffmpeg_tag_maps.

Allow using this function without the ffmpeg_tag_map struct.

Eliminate some duplicate code.

Move the #ifdefs out of _copy_metadata().

No interest in this return value.

Require libavutil 51.5.0.

This function was added when the libavformat version was 53.2.0, but
the actual release 53.2.0 did not have it.

Needed for av_rescale_q() in ffmpeg 0.8.

avcodec_open() has been deprecated.

It's a no-op and deprecated.

URLContext is deprecated.

Support ancient ffmpeg versions.

When we don't have enough data, generate some silence, hoping the
input buffer will fill soon.  Reducing the render buffer size is not
legal.

Blocking inside the render callback is forbidden, and this sleep call
didn't make any sense.

Moving songs using either 'move' or 'moveid' to position -1 (after the
current song) would fail for a song which is just before the current
song.
This patch corrects the check to see if the current song is in the range
to be moved. Since the range is from `start` up to `end` (exclusive) the
check was incorrect, but is now fixed.

The OpenAL specification says that AL_FORMAT_MONO8 and
AL_FORMAT_STEREO8 expect unsigned 8 bit samples, but MPD uses unsigned
samples.

The local variable was already divided by 1000, and the return value
was being divided by 1000 again - doh!  This caused delays in the
httpd output plugin that were too small by three orders of magnitude,
and the buffer was filled too quickly.