Add GMutex, GCond attributes which will be used by callers to
conditionally wait on the stream.

Remove the (now-useless) plugin method buffer(), wait on GCond
instead.  Lock the input_stream before each method call.  Do the same
with the playlist plugins.

According to the mantis bug report 2847, there are several possible
variations of the "album artist" tag:

- "album artist"
- "album_artist"
- "albumartist"

This patch adds support for the latter two.

We already supported "albumartist", but it seems some folks also use
"album artist" (with a space).

Allocate the "tag" object after the file has been checked.  That
removes one tag_free() call in an error handler.

Allocate only one item on the stack.

Reuse the function tag_name_parse_i().

I'm not sure if mapping "band" to TAG_PERFORMER is correct, but it
might be better than nothing.

Convert if/else/else/... to a loop.

The underlying library is named "libmp4ff".  To reduce confusion,
rename the plugin to a more specific name.

Make it X_decoder_plugin.c.

This function replaces the replay_gain_info parameter for
decoder_data().  This allows the decoder to announce replay gain
changes, instead of having to pass the same object over and over.

This patch changes the following decoder plugins to implement
stream_tag() instead of tag_dup():

 faad, ffmpeg, mad, modplug, mp4ff, mpcdec, oggflac

This simplifies their code, because they do not need to take care of
opening/closing the stream.

Remove the data_time parameter from decoder_data().  This patch
eliminates the timestamp counting in most decoder plugins, because the
MPD core will do it automatically by default.

This patch prepares support for floating point samples (and probably
other formats).  It changes the meaning of the "bits" attribute from a
bit count to a symbolic value.

Let the audio_check library verify the audio format in all (relevant,
i.e. non-hardcoded) plugins.

After we've been hit by Large File Support problems several times in
the past week (which only occur on 32 bit platforms, which I don't
have), this is yet another attempt to fix the issue.

It makes no difference right now, but we're about to add an endianness
flag and will want to make sure it's correctly initialised every time.

strcasecmp() is locale dependent, making it a bad choice for internal
string comparisons.

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.

When mp4ff_read_sample() returns a value bigger than zero, it
guarantees that the buffer is set.  Remove the check.

Don't waste any precious memory when the seek_table cannot be used.

Don't include limits.h, use GLib constants instead.

Use faacDecInit2() instead of AudioSpecificConfig() to detect the AAC
track in the MP4 file.  This has a great advantage: it initializes the
libfaad decoder, which the caller would normally do anyway - but now
we can go without the AudioSpecificConfig() call.  When decoder==NULL
(called from mp4_tag_dup()), fall back to a mp4ff_get_track_type()==1
check, like other audio players do.

Moved the libfaad decoder initialization to mp4_faad_new(), and also
fill the audio_format struct there.  This eliminates a little bit of
complexity in mp4_decode().

Don't wait for the first frame to be decoded.  We already have the
sample rate and the channel count from faacDecInit2().

The function mp4_load_tag() is used only once, and mp4_tag_dup() is a
one-liner.  Merge them.

Fixed the log domains of the renamed decoders.  Added G_LOG_DOMAIN
macros in decoders which don't have one already.

This plugin is based on "libmp4ff".

On some platforms, g_free() must be used for memory allocated by
GLib.  This patch intends to correct a lot of occurrences, but is
probably not complete.

Some plugins used the APE or ID3 tag loader as a fallback when their
own methods of loading tags did not work.  Move this code out of all
decoder plugins, into song_file_update().

I tried to search for a certain composer in my collection, but only
non-mp4 files showed up. The source code reveals that this tag is not
read. This can be fixed by reading the 'Writer' tag field, in
mp4_plugin.c, in function mp4_load_tag.

I actually tried this, and after compiling with those lines added,
also mp4 (.m4a) files showed up when searching for a composer.

Refuse to play audio formats which are not supported by MPD.