The API of mp4_load_tag() was strange: it always returned a tag
object, no matter if a tag was found in the file; the existence of a
tag was indicated with the tag_found integer reference. This flag is
superfluous, since we can simply check whether the tag is empty or
not.
Allocate the mp4ff_callback_t object on the stack. This is easier to
handle, since we don't have to free it. Incidentally, this fixes a
memory leak in mp4_load_tag().
The function decoder_read() already cares about the decoder command,
and loops until data is available. Reduced mpd_ffmpeg_read() to no
more than the decoder_read() call.
The variable "next_song" is already protected by a memory barrier.
"total_time" is not important for synchronization, and we don't need
"volatile" here.
If an input stream provides tags (e.g. from an icecast server), send
them in the decoder_data() and decoder_tag() methods. Removed the
according code from the mp3 and oggvorbis plugins - decoders shouldn't
have to care about stream tags.
This patch also adds the missing decoder_tag() invocation to the mp3
plugin.
MPD used to have a copy of the mp4ff library. Since that has been
removed, AAC suport was disabled when there was no libmp4ff. Separate
the libmp4ff test, and enable AAC support no matter if libmp4ff is
available.
The "mod" decoder plugin was being initialized lazily, but was
deinitialized unconditionally. That led to segmentation faults.
Convert mod_initMikMod() to be the global module initialization
method. The MPD core should care about lazy initialization.
Non-local songs used to have no tags. If the decoder sends us a tag,
we should incorporate it into the song struct. This way, clients can
always show the correct song name (if provided by the server).
The try_decode() method may have read some data from the stream, which
is now lost. To make this data available to other methods, get it
back by rewinding the input stream after each try_decode() invocation.
The ogg and wavpack plugins did this manually and inconsistently; this
code can now be removed.
If the source chunk has a tag, merge it into the destination chunk.
The source chunk gets deleted after that, and this is our last chance
to grab the tag.
Ogg and ffmpeg detection was disabled when the stream was not
seekable, because the detection was too expensive. Since the curl
input stream can now rewind the stream cheaply, we can re-enable
detection on streams.
During codec detection, the beginning of the stream is consumed. This
is a common operation, which takes a lot of time when handling remote
resources. To optimize this, remember the first 64 kB of a stream.
This way, we can rewind the stream without actually fetching the start
of the stream again.
