BGM for non-story scenes settings

[qwqeftrhk]

I've been able to find the background images for the various scenes not in the story menu/title, credits, etc and similar stuff like the extra menu, but I still can't find whatever file chooses what music to play on them. I'd like to be able to find the settings for the title, extra menu when accesed from the title screen and the credits if I am able to. I'm currently under the assumption it's either an epk or somewhere in the GUI files (maybe a .gut), but with no idea where I'm looking, I'm kind of searching blindly. I apologise if you have no idea either or if this is just too big an ask, but do you know where they are or at least are likely to be?
(And if so are they editable?)

[kurikomoe]

Wow, are you able to decrypt the .fcd files? I haven't looked into them yet.
It seems that some of the BGMs are embedded directly inside the main .exe file:

Here is the list of the embedded BGMs:

bgm01.fcd
bgm28.fcd
bgm45.fcd
bgm46.fcd
bgm60.fcd
bgm68.fcd
bgm68
bgm76.fcd
bgm70
bgm51
bgm40
bgm44.fcd

Based on the data extracted from bgm_data.epk, we have the following metadata:

DAT
id=qid::label=str::flag_index=i::sort=i::finename=str::title=lstr::
1::MUSIC_CLEAR_FLAG_01::1::1::bgm01::into the night::
2::MUSIC_CLEAR_FLAG_03::2::2::bgm03::日差しの中で::
3::MUSIC_CLEAR_FLAG_04::3::3::bgm04::穏やかな毎日::
4::MUSIC_CLEAR_FLAG_05::4::4::bgm05::優しい風景::
5::MUSIC_CLEAR_FLAG_06::5::5::bgm06::茜色の街::
6::MUSIC_CLEAR_FLAG_07::6::6::bgm07::笑顔に囲まれて::
7::MUSIC_CLEAR_FLAG_08::7::7::bgm08::真夜中の狭間::
8::MUSIC_CLEAR_FLAG_35::8::8::bgm35::彷徨う影::
9::MUSIC_CLEAR_FLAG_09::9::9::bgm09::悪夢::
10::MUSIC_CLEAR_FLAG_10::10::10::bgm10::運命の渦::
11::MUSIC_CLEAR_FLAG_43::11::11::bgm43::運命の渦２::
12::MUSIC_CLEAR_FLAG_11::12::12::bgm11::激突する魂::
13::MUSIC_CLEAR_FLAG_12::13::13::bgm12::破滅の足音::
14::MUSIC_CLEAR_FLAG_13::14::14::bgm13::突破口::
15::MUSIC_CLEAR_FLAG_14::15::15::bgm14::丘の上の教会::
16::MUSIC_CLEAR_FLAG_15::16::16::bgm15::追憶の彼方::
17::MUSIC_CLEAR_FLAG_16::17::17::bgm16::消えない想い::
18::MUSIC_CLEAR_FLAG_17::18::18::bgm17::二人の時間::
21::MUSIC_CLEAR_FLAG_19::21::21::bgm19::求め合う心::
22::MUSIC_CLEAR_FLAG_24::22::22::bgm24::疾風の剣士::
23::MUSIC_CLEAR_FLAG_20::23::23::bgm20::約束された勝利の剣::
24::MUSIC_CLEAR_FLAG_21::24::24::bgm21::黄金の王::
25::MUSIC_CLEAR_FLAG_23::25::25::bgm23::エミヤ::
26::MUSIC_CLEAR_FLAG_34::26::26::bgm34::光と闇::
27::MUSIC_CLEAR_FLAG_25::27::27::bgm25::この世全ての悪::
28::MUSIC_CLEAR_FLAG_45::28::28::bgm45::新たな夜明け::
29::MUSIC_CLEAR_FLAG_46::29::29::bgm46::新たな夜明け２::
31::MUSIC_CLEAR_FLAG_49::31::31::bgm49::THIS ILLUSION (inst.)::
32::MUSIC_CLEAR_FLAG_18::32::32::bgm18::THIS ILLUSION (piano ver.)::
33::MUSIC_CLEAR_FLAG_42::33::33::bgm42::静かなる声::
34::MUSIC_CLEAR_FLAG_29::34::34::bgm29::嵐の予感::
35::MUSIC_CLEAR_FLAG_39::35::35::bgm39::ローレライ::
36::MUSIC_CLEAR_FLAG_44::36::36::bgm44::今日の食卓::
37::MUSIC_CLEAR_FLAG_28::37::37::bgm28::extra::
38::MUSIC_CLEAR_FLAG_58::38::38::bgm58::うららかな調べ::
39::MUSIC_CLEAR_FLAG_59::39::39::bgm59::トラブルメーカーズ::
40::MUSIC_CLEAR_FLAG_64::40::40::bgm64::心のチャイム::
41::MUSIC_CLEAR_FLAG_67::41::41::bgm67::タイガー道場のテーマ::
42::MUSIC_CLEAR_FLAG_75::42::42::bgm75::魔刻::
43::MUSIC_CLEAR_FLAG_61::43::43::bgm61::対峙::
44::MUSIC_CLEAR_FLAG_72::44::44::bgm72::Sonic Barrage::
45::MUSIC_CLEAR_FLAG_62::45::45::bgm62::Burst Up::
46::MUSIC_CLEAR_FLAG_57a::46::46::bgm57a::Diver::
47::MUSIC_CLEAR_FLAG_57b::47::47::bgm57b::Diver２::
48::MUSIC_CLEAR_FLAG_56::48::48::bgm56::根源の龍::
49::MUSIC_CLEAR_FLAG_63a::49::49::bgm63a::侵食::
50::MUSIC_CLEAR_FLAG_63b::50::50::bgm63b::侵食２::
51::MUSIC_CLEAR_FLAG_65::51::51::bgm65::深き眠り::
52::MUSIC_CLEAR_FLAG_74::52::52::bgm74::Sorrow::
53::MUSIC_CLEAR_FLAG_73::53::53::bgm73::神の名のもとに::
54::MUSIC_CLEAR_FLAG_53::54::54::bgm53::蘇る神話::
55::MUSIC_CLEAR_FLAG_71::55::55::bgm71::二人の王::
56::MUSIC_CLEAR_FLAG_54::56::56::bgm54::最後の力::
57::MUSIC_CLEAR_FLAG_66::57::57::bgm66::Mighty Wind::
58::MUSIC_CLEAR_FLAG_55::58::58::bgm55::約束された勝利の剣 (Black Saber mix)::
59::MUSIC_CLEAR_FLAG_60::59::59::bgm60::Blue Sky::
60::MUSIC_CLEAR_FLAG_68::60::60::bgm68::移りゆく季節 (Realta Nua ver.)::
62::MUSIC_CLEAR_FLAG_70::62::62::bgm70::Link (short ver.)::
63::MUSIC_CLEAR_FLAG_52::63::63::bgm52::夢の終わり::
64::MUSIC_CLEAR_FLAG_77::64::64::bgm77::EMIYA

By cross-referencing the embedded files with the database, we get the mapping below:

Note: Since I haven't played the game myself, I cannot perfectly associate every BGM with its exact in-game context. The usage scenarios below are just educated guesses made by me and AI.

文件名 (EXE 硬编码)	数据库对应 ID	曲名 (Title)	场景推测 (Usage)
bgm01.fcd	1	into the night	初始主界面 (Title Screen) / 序章
bgm28.fcd	37	extra	Extra Menu (额外菜单)
bgm44.fcd	36	今日の食卓	菜单背景或日常系统界面
bgm45.fcd	28	新たな夜明け	结局界面 / 演职员表 (Ending 1)
bgm46.fcd	29	新たな夜明け２	结局界面 / 演职员表 (Ending 2)
bgm60.fcd	59	Blue Sky	结局/通关后的特定展示界面
bgm68.fcd	60	移りゆく季節 (RN ver.)	通关后的特殊主界面 / Last Episode
bgm70	62	Link (short ver.)	可能是特定路线的后记/Credits
bgm76.fcd	(未在DAT中)	未知	极大概率是 Last Episode 专用曲
bgm51	(ID匹配?)	深き眠り (bgm65?)	对应 ID 51 的 bgm65，可能是系统占位符
bgm40	(ID匹配?)	心のチャイム (bgm64?)	对应 ID 40 的 bgm64

also, there are tons of se files defined in the exe:

[kurikomoe]

Here is some code to help clarify things:

[kurikomoe]

To answer your question:
yes, these BGMs are editable (though simply swapping the filenames should be enough.)

Anyway, if you want to change something, just modify the .exe file or provide a hook .dll.

maybe~~

场景功能	核心控制函数	默认定义的 BGM (硬编码)
初始主界面 (Title)	sub_1402467D0	bgm01.fcd
全通关后主界面	sub_1402467D0	bgm45.fcd (或 bgm68)
额外菜单 (Extra)	sub_1402467D0	bgm28.fcd
结局演出 (Ending/Credits)	sub_14008C4E0	bgm68.fcd, bgm76.fcd
通关结算页 (Clear Screen)	sub_1400A1B50	bgm46.fcd, bgm60.fcd

[kurikomoe]

Ok, I spent some time analyzing the FCD.

All fcds are dumped, check this dec.py

Repacking the .ogg files back into the .fcd format should be possible. Simply adding the appropriate header and treating the file as an unencrypted type might work (though this is currently untested)."

[qwqeftrhk]

How do you edit the main .exe? I'm trying to in hex-editor, and it keeps causing game crashes when I try to replace the title music.
"Application load error 3:0000065432" to be exact. I've tried changing it back also using a hex editor, and then it doesn't crash so my best guess is there's another piece of code in the .exe or elsewhere tied to it that I'm breaking by changing it.

[kurikomoe]

How do you edit the main .exe? I'm trying to in hex-editor, and it keeps causing game crashes when I try to replace the title music. "Application load error 3:0000065432" to be exact. I've tried changing it back also using a hex editor, and then it doesn't crash so my best guess is there's another piece of code in the .exe or elsewhere tied to it that I'm breaking by changing it.

I'm not exactly sure what you've edited. However, since the game is protected by Steam DRM, simply modifying the .exe directly will likely cause it to crash.

Here is an example mod: I changed the title screen BGM from BGM01 to BGM03.

To use it, just place version.dll and changebgm.asi in the same folder as fsn2-win64vc14-release.exe.

change_bgm_mod.zip

The .ogg files included in the zip are just for demonstration purposes; the patch itself doesn't depend on them.

[qwqeftrhk]

Thank you. Do you know if this will change the music for where BGM01 would play in-game? I'm assuming this is because I'm running the game on linux using a steam compatibility layer, but sadly it doesn't work for me either.

[kurikomoe]

Thank you. Do you know if this will change the music for where BGM01 would play in-game? I'm assuming this is because I'm running the game on linux using a steam compatibility layer, but sadly it doesn't work for me either.

Of course, Linux will require some extra steps. I think you need to change this (I don’t have the game, so the image is just an example):

WINEDLLOVERRIDES="version=n,b" %command%

Q: Do you know if this will change the music for where BGM01 would play in-game?
A: This patch only changes the title screen music from BGM01 to BGM03. If you want to globally replace the BGM, I believe replacing bgm03.fcd with bgmXX.fcd should work.

[qwqeftrhk]

Sad to say it does not work even with that, but thank you for all the advice/ just telling me what to do so far.

[kurikomoe]

No problem at all. Sorry it didn't work out. I don't actually have the Steam version, or else I'd jump into a Linux environment and test the DRM and the latest update for you.

[qwqeftrhk]

Thanks for all the help, you've really gone above and beyond what I expected, considering I came here asking what files I should extract and you've made all these tools. Because I can't get the .dll to work, I'll probably have to take the longer route of renaming the .fcd I want to play and then changing the (I believe .ks or .epk files) for story scenes to change what .fcd plays there too.
Like I say, thanks so much for all of this even if it turned out that stuff like my OS was ruining the solution.