==== MPEG4_audio_extension_descriptor

Defined by MPEG in <<ISO-13818-1>>.

The _audioSpecificConfig_ structure is defined in <<ISO-14496-3>>.
Currently, it can only be represented as a binary blob in hexadecimal characters.
Some future version may be able to describe the internal structure of this data block.

[source,xml]
----
<MPEG4_audio_extension_descriptor>

  <!-- Up to 15 audioProfileLevelIndication values -->
  <audioProfileLevelIndication value="uint8, required"/>

  <!-- Binary structure as defined in 1.6.2.1 in ISO/IEC 14496-3 -->
  <audioSpecificConfig>
    Hexadecimal content
  </audioSpecificConfig>

</MPEG4_audio_extension_descriptor>
----
