libavformat 0.6 does not pass the original URI pointer to the "open"
method, which leads to a crash because MPD was using a dirty hack to
pass a pointer to that method.

This patch switches to av_open_input_stream() with a custom
ByteIOContext class, instead of doing the URI string hack with
av_open_input_file().

Loosely based on a patch from Jasper St. Pierre.

Use the libavformat function av_probe_input_format() to probe the
AVInputFormat, instead of letting av_open_input_file() do it
implicitly.  We will switch to av_open_input_stream() very soon, which
does not have the probing code.

Loosely based on a patch from Jasper St. Pierre.

Free the string allocated by decoder_get_uri().

This fixes a theoretical crash, which has never occurred in practice.

Fix a memory leak in some code paths.

Replace the check for avcodec_decode_audio2(), assume it's present in
libavcodec version 51.

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

I've attached a patch that will make file URIs work on operating systems
that provide the getpeereid() function call to check the user ID of the
peer connected to a UNIX domain socket.

There is no useful return value here.

The return value of Player_LoadTitle() is allocated with malloc(), and
must be freed by the caller.

Reuse the function tag_name_parse_i().

Reuse the function tag_name_parse_i().

Convert a string into a tag_type enum.

Initialize the ov_callbacks struct at compile time.

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.

Allow code sharing.

I took this tag name from a MusePack sample file I got from a user.
It is not documented in the APE specification:

 http://wiki.hydrogenaudio.org/index.php?title=APE_key

People seem to be using undocumented extensions to the specification
anyway, and the best we can do is attempt to support them.

Make "enum tag_type" the array index, and convert apeItems to a sparse
array.

Improve code readability.

Don't initialize those arrays each time tag_ape_load() is called.

Without libid3tag, we were trying to skip the ID3 frame (since
0.15.2).  Its length however was not calculated at all, we were just
dropping everything from the current input buffer.  This lead to the
first few seconds of the file being skipped.  This patch attempts to
calculate the ID3v2 frame size with the formula from:

 http://www.id3.org/id3v2.4.0-structure 3.1 and 6.2

"When playing musepack files with mpd v0.15.8, rg seems to have no effect.

Using sample file below, mpd says 'computing ReplayGain album scale with gain 122.879997, peak 0.549150'.

One thing though, if I build mpd against old libmpcdec-1.2.6, rg works
as expected: 'computing ReplayGain album scale with gain 16.820000,
peak 0.099765'"

Previously, tags of the new song being cross-faded in were sent
immediately.  That can cause wrong information being displayed,
because the "previous" song might send its tag at the end again,
overriding the "next" song's tag.  This patch saves & merges the tag
of the next song, and sends it when cross-fading is finished, and the
next song really starts.

Like tag_merge(), but can deal with NULL parameters, and frees both
tag objects.

"There is a bug in fixed-point musepack (musepack_src_r435) playback.
In floating-point audio is OK but in fixed audio is distorted.  I have
made a patch for this"