Syplheed-Reborn/docs/re/structures/sound-pak-contents.md

What is actually in sound.pak — and the language substitution

✅ Settled 2026-08-26. sound.pak's 9 519 entries are almost entirely accounted for: the Japanese voice set, the English voice set, and 35 music / jingle banks. The FILES record in tables.pak names the Japanese half, and the game reaches the English half by substituting the leading directory.

Until now the corpus described sound.pak as "~9 519 headerless entries, params in an unknown table". The table is sound-cue-table.md, and this page is the census.

The name is the key

Every path in FILES hashes straight into the sound.pak TOC with name_hash — 5 135 of 5 135, using the path exactly as stored (backslashes, case-insensitive):

jpn\etc\VOICE_D_257.slb  ->  name_hash  ->  TOC entry (offset, size)

No transformation, no prefix, no stem. Taking the basename instead resolves only 35 — precisely the 35 root-level BGM_* / JNGL_* banks whose basename is their path, which is the control that shows the full path is what matters.

This is not luck: the hash's low 24 bits are a residue mod 0x00FFF9D7 and the top byte is a byte-sum, so for 5 135 probes against 9 519 occupied slots the expected number of accidental hits is about 0.01.

The census

what	entries
jpn\… — named directly by FILES	5 100
eng\… — the same names with the directory substituted	4 382
BGM_*.slb, JNGL_*.slb at the root	35
total accounted	9 517
TOC total	9 519

2 entries are unaccounted for. I did not identify them.

Only eng and jpn resolve. deu, fra, ita, esp and the alternative spellings fre/ger/spa produce zero hits, which is the measurement behind the claim that only two voice sets are shipped — the other four languages are subtitle-only.

718 of the 5 100 Japanese banks have no English counterpart. That is consistent with the previously recorded finding that a set of lines exists only undubbed, and it puts a number on it from the archive side.

❌ CORRECTED the same day — see slb-data-offset.md. The section below measures correctly but concludes wrongly. The Japanese banks are not a different layout: the leading-stream offset is first_riff % 2048, which is 1392 only in <lang>\etc\. Every "misaligned" row here is a bank being decoded mid-packet, in English as well as Japanese. The numbers stand as a measurement of the old constant's reach; the interpretation does not.

⚠️ The leading-region rule is English-only

This is the part that matters most, and it bounds an existing result.

voice-bank-leading-region.md established the hybrid layout: a bank may carry a leading headerless XMA1 region before its first RIFF, recognised by the first RIFF sitting exactly at 1392 + n·2048. That was derived from VOICE_D_450–454, and it reproduces exactly — all five, at 16 384 / 2 048 / 14 336 / 45 056 / 59 392 bytes, matching the recorded figures to the byte. The pipeline is sound.

But those five are eng\etc\ banks, and the rule does not generalise:

set	aligned	misaligned	no RIFF	first RIFF ≤ 1392
eng\… (4 382)	1 571	2 060	696	55
jpn\… (5 100)	0	4 301	799	—

Not one of the 5 100 Japanese banks satisfies the alignment condition. The rule describes a third of the English set and none of the Japanese set.

Being careful about what that does and does not mean: "misaligned" only means the leading-segment branch does not fire, and to_xma_riffs still walks the bank's sub-waves normally — so this is not evidence that those banks are broken. What it does mean is that the leading-region finding is a property of some English banks, not of .slb in general, and any code or documentation that treats it as the bank format is overreaching. The Japanese banks are laid out differently and that layout is not decoded.

How I nearly got this wrong

I first resolved the five documented banks through their FILES paths, which are jpn\etc\…, and got leading regions of 59 600 / — / 6 352 / 14 544 / 28 880 — none a multiple of 2 048, none matching the recorded figures. The tempting reading was that my extraction was broken. The alignment condition is what said otherwise: a broken reader would not produce exactly the recorded numbers for eng\etc\, which it then did, for all five. The extraction was right and the assumption that FILES' path was the one the corpus had measured was wrong.

What this does not settle

• The 2 unaccounted TOC entries.
• The Japanese bank layout. 4 301 banks have a RIFF at an unaligned offset and 799 have none at all; neither shape has been decoded, and no Japanese bank has been decoded to audio here.
• Why 55 English banks have their first RIFF at or before 1392, inside what the headerless reading treats as the header.
• Nothing here was run. This is a static census of the archive.