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PostPosted: Sat Jan 12, 2019 12:00 am 
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I want to replace some of the music and sounds in Zelda 2. I have the game disassembled, but I don't know how to go about editing the music. I need help.


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PostPosted: Sat Jan 12, 2019 11:30 am 
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Romhacking.net's Data Crystal wiki page for Zelda II: The Adventure of Link has a "Zelda II Music Document". The hex locations in that document are offsets in the .NES file.


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PostPosted: Sat Jan 12, 2019 12:48 pm 
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2 methods.

Figure out exactly what the music code does.

or.

Find the music data, and just corrupt it and see what happens.


another thought. go somewhere where nothing is going on, but music plays such as the title screen., and look at the RAM in a debugger. The zeropage RAM almost certainly has some pointers to music data, they tell you where the data is.

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PostPosted: Sun Jan 13, 2019 9:03 am 
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I have the Music document from RHDN, and I have a disassembly. I can find the music, but the info only talks about how to change pitch and tones. What I need to figure out is how to replace a song with a different song not currently in the game.


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PostPosted: Sun Jan 13, 2019 11:25 am 
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According to that doc, the songs are built from a sequence of phrases. You'll need to divide your music into phrases, then make that "phrase order" table that points to your phrases so they'll play in the order you want.


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PostPosted: Sun Jan 13, 2019 6:21 pm 
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UltimaWeapon wrote:
I have the Music document from RHDN, and I have a disassembly. I can find the music, but the info only talks about how to change pitch and tones. What I need to figure out is how to replace a song with a different song not currently in the game.

The doc is explaining it in Lego block detail, and you want it as a pre-made Lego building. I'm afraid you'll have to build your song up in Lego block detail in the format and arrangement that Zelda 2's music engine expects.

By the way, almost every old game system games' music engine / driver is unique from one another. There is no standard music format for them, let alone a human-readable one.

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PostPosted: Fri Jan 18, 2019 7:19 pm 
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ccovell wrote:
The doc is explaining it in Lego block detail, and you want it as a pre-made Lego building. I'm afraid you'll have to build your song up in Lego block detail in the format and arrangement that Zelda 2's music engine expects.

Or...

You can do something like this and replace the music engine with your own:

https://youtu.be/_Hx4QUNsTiw

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PostPosted: Wed Jan 23, 2019 11:25 am 
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Jedi QuestMaster wrote:
ccovell wrote:
The doc is explaining it in Lego block detail, and you want it as a pre-made Lego building. I'm afraid you'll have to build your song up in Lego block detail in the format and arrangement that Zelda 2's music engine expects.

Or...

You can do something like this and replace the music engine with your own:

https://youtu.be/_Hx4QUNsTiw


How do I go about replacing the music engine with my own?


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PostPosted: Wed Jan 23, 2019 11:27 am 
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Quote:
with my own?


Are you going to rewrite one from scratch? Or use one of the existing homebrew music engines?

Also, adding VRC7 support would require more changes than just the music code.

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Last edited by dougeff on Wed Jan 23, 2019 11:29 am, edited 1 time in total.

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PostPosted: Wed Jan 23, 2019 11:29 am 
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Replacing a game's entire audio driver is a fairly invasive hack that requires you to know, among other things, how to program in 6502 assembly language and how to use ROM and RAM maps (or, if they don't exist, how to make one). The appropriate description of the process depends on your level of assembly experience.

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PostPosted: Sun Jan 27, 2019 7:13 pm 
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dougeff wrote:
Find the music data, and just corrupt it and see what happens.



Do it! DO IT!!!!


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