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.

Let the codec start with fresh buffers.  This should fix the remaining
seeking issues.

Use AVStream.time_base to convert the decoder_seek_where() value, and
pass the current stream number to av_seek_frame().

Use flag AV_TIME_BASE.

Code simplification.

av_open_input_stream() has been deprecated.

AVMetadata has been deprecated.

It's a no-op and deprecated.

avcodec_decode_audio3() has been added in libavformat 52.25.0, and the
predecessor avcodec_decode_audio2() has been deprecated.

fixes build with lavc 53.

For ffmpeg < 0.5.  Copied from libavutil 0.5.

avcodec_decode_audio3() has been added in libavformat 52.25.0, and the
predecessor avcodec_decode_audio2() has been deprecated.

All modern distros ship 0.5, so there's no need to support old and buggy
ffmpeg versions.

.. instead of av_get_bits_per_sample_format().  The SampleFormat enum
value is authoritative.

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.

in some formats, e.g. vorbis, the metadata is stored per-stream.

What's happening is the `ptr' argument to that function is NULL for me
every time. `ptr' is unconditionally dereferenced to generate a log
message, and this is where mpd crashes.

Attached is a simple patch that tests for NULL and omits the log. With
this patch the crash disappeared and mpd went back to working well.

Pass everything to the GLib logging library.  No direct stderr access.

The pointer is invalid if av_open_input_file() fails.

Don't use the function ffmpeg_helper(), don't initialize the codec.

Fix a memory leak in some code paths.

Use input_stream.uri.

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.