Buzztard-dec

Have a gstreamer element that can decode buzztard songs. This would allow to play buzztard songs in all gstreamer media players.

Audio sink

Instead of playing the audio ourself we need to output raw audio so that it can be plugged in playbin(2).

Dummy sink

One way would be to provide a dummy btsinkmachine that it will set as a master. As btsinkmachine always uses btsinkbin, the later needs a pass-through mode (we already have the record modes). I don't see a way to avoid sink-bin right now.

The bin needs to set the src-pad of the sink-bin's last element (input-gain) as a ghost-pad for itself (we could make it a sometimes pad maybe if we want to add a pad-template). Also the actual BtSinkMachine woul need to have such a ghostpad.

Passthrough mode on sinkbin

We need passthrough mode on sinkbin anyway. Sinkbin would be a sometimes src-pad. In passthrough mode it would add a pad for raw-audio. Also sinkmachine would get such a sometimes pad. It will listen for new pads on sink-bin and add a sometimes pad too.

Typefinders

We somehow need to wrap the songio-detect mechanism into a typefinder. This is needed so that playbin would actually autoplug this element.

Loading

We need to check from e.g. timidity/wildmidi as they also need to have the full song loaded. We need API on song-io plugins to load from memory (right now the set the file-name on the song-io object, now they would need to set memory-ptr and length instead (easy doable, see todo: comments in the source) - using a gio stream would be nice too).

We need tu turn bt_song_io_make() into bt_song_io_make_from_file() and add bt_song_io_make_from_memory().

  // prepare song and song-io
  song=bt_song_new(BT_APPLICATION(self));
  if(loader=bt_song_io_make_from_memory(buffer,size)) {
    if(bt_song_io_load(loader,song)) {
      // ...
    }
  }

Right now bt_song_io_make() will run bt_song_io_detect() which again needs a file-name as it only checks extensions. As a hack we could use gst_query_new_uri() in bt_song_io_make_from_memory():

BtSongIO *bt_song_io_make_from_memory(gpointer buf, gsize len) {
  BtSongIO *self=NULL;
  GType type = 0;
 
  // can't query here, as we don't have the bin :/
  type=bt_song_io_detect(file_name);
  if(type) {
    self=BT_SONG_IO(g_object_new(type,NULL));
    if(self) {
      self->priv->buf=buf;
      self->priv->len=len;
    }
  }
  else {
    GST_WARNING("failed to detect type for filename %s",file_name);
  }
  return(self);
}