+ * \note The Ogg FLAC mapping requires that the VORBIS_COMMENT block be
+ * the second metadata block of the stream. The encoder already supplies
+ * the STREAMINFO block automatically. If \a metadata does not contain a
+ * VORBIS_COMMENT block, the encoder will supply that too. Otherwise, if
+ * \a metadata does contain a VORBIS_COMMENT block and it is not the
+ * first, this function will reorder \a metadata by moving the
+ * VORBIS_COMMENT block to the front; the relative ordering of the other
+ * blocks will remain as they were.
+ *
+ * \note The Ogg FLAC mapping limits the number of metadata blocks per
+ * stream to \c 65535. If \a num_blocks exceeds this the function will
+ * return \c false.
+ *