Just a start...

Document which commands were introduced after MPD 0.13.

When the decoder is finished, break out of the player loop only after
another player.pipe check.  We did check the pipe size a few lines
above, but that check was kind of racy.

When a music_chunk only contains a tag but no PCM data, play_chunk()
returns true without freeing the chunk.  The caller now assumes that
the chunk is moved into some music_pipe and does not bother to free it
either.

To check for leaked music_chunk objects, free the music buffer on
CLOSE_AUDIO.  This invokes an assertion check which ensures that all
chunks have been returned to the buffer.

Instead of returning the local variable "ret" which is always true at
this point, hard-code the "true" return value, because that might be
more readable.

If a file is removed the library, next time mpd will try to play it it
will result in an error 'ERROR: problems decoding some/file.ogg'.
Nothing is written in log files (verbose mode or not)

[mk: append strerror(errno)]

Make gcc warn us if we add a new mixer type, and forget to add a new
"case" line.

Don't use CPP macros when you can use C enums.

Commit f78cddb4 introduced a regression: when the playlist reached its
end, MPD did not reset the "current song" pointer anymore after stop.
Add a "current = -1" code line.

[mk: moved check out of the AC_ARG_WITH block]

Append $FAAD_LIBS to $LIBS when detecting libmp4ff.  $FAAD_LIBS may
contain an important -L flag.

The old sticker.xml used elements which are not valid in DocBook.  Now
that the file is valid, let's add it to $(DOCBOOK_FILES).

The M4 function AM_PATH_LAME (m4/lame.m4) defined a configure flag
named "--disable-lametest".  This is redundant with configure.ac's
--disable-lame-encoder, and specifying both options may break the
build.  Since AM_PATH_LAME is only called when the encoder plugin is
enabled, we can safely remove that --disable-lametest option.

Check the validity of the audio_format during write operations.

Always assert that the audio format of the new chunk is valid.

Hello,

While compiling latest git I've received a compile error in the
httpd_output_plugin.
Small patch attached.

Patrik

The string comparison should be "!= 0", not "== 0".  Ouch.

The player thread must reset pc.next_song after seeking, even if that
operation has failed.  This patch adds an assertion.

The only pc_seek() caller clears the error, rendering the check
useless.  Even if the previous PLAY command resulted in a player
error, this check is not very useful.

Renamed playerSeek() to pc_seek() to get rid of CamelCase.  Convert
the return value to bool.

If the UFID frame's owner is "http://musicbrainz.org", assume its
value is the MusicBrainz track id.

Flush the encoder before calling encoder_tag().  The first page
generated by the encoder after sending the tag will be the new
"header" page, which is sent to all HTTP clients when they connect.
This is a little bit specific to the vorbis encoder, but there are no
other encoders which support tags (yet).

Moved some code from httpd_output_encode_and_play() into separate
functions httpd_output_broadcast_page() and
httpd_output_encoder_to_clients().

There's no reason to send both encoder tags and Icy-Metadata to the
client.  Let's disable Icy-Metadata when the encoder supports embedded
tags.

When a new tag is set, end the current stream and begin a new one.
Use vorbis_analysis_headerout() to write a full ogg header.  This
fixes a problem with icecast: after a song change in MPD, icecast
stops forwarding ogg packets to its clients.

In the tag() method, MPD guarantees that it does not pass tag==NULL.
Converted the runtime check to an assertion.

The second parameter of zzip_dir_open() is a pointer.  Pass the NULL
pointer instead of 0 (with implicit conversion at compile time).

Don't loop over source files, do all checks in one run.