Author: HobbitDur

  1. Sounds
    1. Header
    2. AKAO sequence block header
    3. How the PC engine handles this section
    4. The SFX path
    5. Modding implications
    6. Reference (names & addresses)

Sounds

Contains AKAO sound sequences (can be empty). Each sequence is a small block in Square’s AKAO format (magic "AKAO" = 41 4B 41 4F).

Offset Length Description
0 2 bytes Number of AKAOs (nbAKAO)
2 nbAKAO * 2 bytes AKAO positions (u16 each, absolute offset from the start of this section)
2 + nbAKAO * 2 2 bytes End offset (= this section’s length; gives the length of the last AKAO)
4 + nbAKAO * 2 0 or 2 bytes 0x0000 alignment padding, present only when needed to 4-byte-align the first AKAO
(first position) Varies * nbAKAO AKAO sequence blocks

Details:

  • Positions are absolute (relative to the section start), so the parser locates each AKAO directly with positions[i]; it does not add up lengths.
  • The value after the position array (End offset) equals the total section length, i.e. one-past-the-last byte, so len(AKAO[i]) = positions[i+1] - positions[i] with positions[nbAKAO] = End offset.
  • The first AKAO block is always 4-byte aligned. When the header table ends on an unaligned offset, a 0x0000 padding word fills the gap. Example: c0m001 (nbAKAO=3) → table ends at 0x0A, pad 0000, first AKAO at 0x0C; c0m004 (nbAKAO=4) → table ends at 0x0C, no pad.

AKAO sequence block header

Offset Length Description
0x00 4 bytes Magic "AKAO"
0x04 2 bytes Category / sub-type (observed values 1, 2, 3)
0x06 2 bytes 0
0x08 4 bytes Sample-bank id. For category-1 blocks this equals the Sound sample bank bank id (e.g. 301, 302…); for category 2/3 blocks it is 1
0x0C … AKAO sequence body (note/timing command stream)

Typical layout: two category-1 blocks (referencing the file’s embedded sample bank) followed by one or more category-2/3 blocks. Examples:

  • c0m001: 3 blocks — (cat 1, len 80, bank 301), (cat 1, len 80, bank 301), (cat 2, len 124, bank 1)
  • c0m004: 4 blocks — (cat 1, 60, 304), (cat 1, 64, 304), (cat 2, 168, 1), (cat 1, 108, 1)

How the PC engine handles this section

The section is parsed at battle-load time by battle_monster_dat_loader. The whole model blob plus this section is copied into battle work RAM in one shot:

BS_CopyGeometry(dest,
    &file[ offset[0] ],                 // first section start
    offset[9] - offset[0]);             // ...up to (not incl.) the sound sample bank

Because this section (index 8) sits just before the sound sample bank (index 9), it is included in that copy, and a pointer to the copied sounds data is stored on the entity’s command-queue structure (command_queue + 0x28).

The PC port does not play sound from these AKAO blocks: no code path reads the stored sounds pointer back into the audio engine. Monster sound effects on PC are played through the global DirectSound engine, driven by the animation-sequence VM and keyed by IDs held in the executable — see The SFX path below. The embedded AKAO sequences are inert on the PC release.

The SFX path

The AnimSeq VM (AnimSeq_DispatchActionOpcode) triggers battle sound with these opcodes:

Opcode Meaning Call
0x97 revival/miss-aware cue linkedToSoundAnimSeq(addr, 0x80)
0x98 cue linkedToSoundAnimSeq(addr, 0x81)
0xB5/0xB6 play actor-local sound linkedToSoundAnimSeq(addr, 0) → BdPlayActorSE
0xB8 play external/global sound linkedToSoundAnimSeq(addr, 1) → BdPlaySy

linkedToSoundAnimSeq reads its operands from the sequence stream:

  • sound_id = addr[0] (byte)
  • flags = addr[1] (byte): bit0 = pan relative to the current target, bit1 = an explicit channel byte follows, bit2 = fixed volume (128)

Resolution of sound_id:

  • BdPlaySy (external) passes sound_id straight to PlayWorldSound.

  • BdPlayActorSE (actor-local): sound_id is 0..6 and indexes a hardcoded per-actor table in the executable, BattleActorSoundTable:

    PlayWorldSound( BattleActorSoundTable[entity->com_id][sound_id], channel_mask, volume, 0x7F );

    BattleActorSoundTable holds 7 DWORD global “world sound” IDs per com_id (monster id) — e.g. entry 0 = 210008, 210009, … These world IDs go through PlayWorldSound → GetSoundID_ForWorld → PlaySound (DirectSound / ADPCM, C:\FF8\Sound\sound.cpp).

The “sound index” in the animation stream is not an index into this section’s AKAO array — it is either a global sound id (0xB8) or a small slot resolved through the executable’s BattleActorSoundTable table (0xB5/0xB6). To change a monster’s battle SFX on the PC release, edit BattleActorSoundTable in the executable, not this section of the .dat.

The full extracted BattleActorSoundTable table (every com_id and its sound slots) and the world-sound id encoding are documented on the Battle actor sound table page.

Modding implications

  • Editing this section’s AKAO blocks has no audible effect on the PC release (the data is parsed but never played).
  • The section must still be kept structurally valid (correct nbAKAO, positions and end offset): battle_monster_dat_loader copies it as part of the model blob and computes downstream pointers from offset[9] - offset[0]. A wrong length for this section shifts every pointer after it.

Reference (names & addresses)

FF8_EN.exe:

Name Address Role
battle_monster_dat_loader 0x507120 Parses the monster .dat; copies sections 1–9 into work RAM
BS_CopyGeometry — Bulk copy of the model blob + this section
AnimSeq_DispatchActionOpcode 0x504BB0 AnimSeq VM opcode dispatcher; issues the sound opcodes
linkedToSoundAnimSeq 0x505AB0 Reads sound_id/flags from the sequence and routes to the players
BdPlayActorSE 0x5015A0 Actor-local SFX; looks up BattleActorSoundTable[com_id][0..6]
BdPlaySy 0x501740 External/global SFX
PlayWorldSound 0x46B2A0 World-sound id → channel/panning → PlaySound
PlaySound 0x4699A0 DirectSound / ADPCM playback
BattleActorSoundTable 0xB8A418 Per-com_id table of 7 world-sound IDs (the actual monster SFX)