==== ISDB_advanced_cable_delivery_system_descriptor

Defined by JCTEA in <<JCTEA-003>>.

Unlike other ISDB descriptors, this one is not fully documented in <<JCTEA-003>>.
It only appears in a block diagram.
The following syntax has been rebuilt from this block diagram.

Exactly one of `<normal_data>` or `<other_data>` shall be present.
With `<normal_data>`, the _descriptor_tag_extension_ is implicitely 0x00.

When `<other_data>` is used and _descriptor_tag_extension_ is 0x01,
the hexadecimal data represent "earthquake warning information".
The data must be 26 to 88 bytes long, structured as follow:

[.compact-list]
* _earthquake_warning_information_ : 204 bits, 25.5 bytes, mandatory.
* _reserved_for_future_use_ : 500 bits, 62.5 bytes, missing bytes are padded using 0xFF.

All other values of _descriptor_tag_extension_ are currently unspecified.

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

  <normal_data
      plp_id="uint8, required"
      effective_symbol_length="uint3, required"
      guard_interval="uint3, required"
      bundled_channel="uint8, required">
    <!-- One per carrier -->
    <carrier
        data_slice_id="uint8, required"
        frequency="uint, frequency in Hz, required"
        frame_type="uint2, required"
        FEC_outer="uint4, required"
        modulation="uint8, required"
        FEC_inner="uint4, required"/>
  </normal_data>

  <other_data descriptor_tag_extension="uint8, default=0x01">
    Hexadecimal content
  </other_data>

</ISDB_advanced_cable_delivery_system_descriptor>
----
