Skeetendo

’Cause all games were better on the GBC

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#1 2016-08-11 01:10:54

Montblanc
Member
Registered: 2016-02-23
Post 37/49

[Gen 1] Sound bug

Hi!

I have found what seems a sound bug I caused to my ROM. It happens "randomly", and so far every time it happens is with the trainer victory song: one of the channels seems to start 5 seconds too late. Turning on and off every channel and comparing the sound to a video I managed to get of it seems it happens to the channel #2.

Is there any way to find what is causing it using bgb debugger or something?  I can always undo things on a backup ROM until it stops, but as it rarely happens and I am unnable to find something in common it will take a lot of time to be sure it is gone...


Edit: Just searched wich adresses in RAM are used for the sound, and compared two savestates when the bug is active or not. The only difference is that $FF16 value is BF when the song is correct and 3F when it is playing wrong.

Last edited by Montblanc (2016-08-11 02:18:24)

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#2 2016-08-11 05:40:35

Ammako
Member
Registered: 2016-03-06
Post 41/90

Re: [Gen 1] Sound bug

This might not help but I found this a while ago (wording makes it sound like you keep backups of previous versions, unless I'm misunderstanding.)

http://www.pokecommunity.com/showthread.php?t=336092

I guess unless/until somebody else comes along with a better answer, this could be something to try in the meantime.

The example here is a GBA hack but I don't see why this would work differently for GB (unless you use disassembly and every new version of the rom becomes massively different or something.)

Last edited by Ammako (2016-08-11 05:42:45)


I get moody during that time of the month. You know, with the full moon and all.

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#3 2016-08-11 17:57:03

Montblanc
Member
Registered: 2016-02-23
Post 38/49

Re: [Gen 1] Sound bug

Thanks for your reply!

Yes, I've made the backups for that purpose, each time I made changes in a new part of the ROM (or a new type of data) the original was left and I made a new file with the changes, so each copy is only a few bytes different. But since the bug happens randomly It will take a lot of time to find wich ROMs are affected and wich ones doesn't, it is not something I can trigger :(

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#4 2016-08-13 02:09:28

Montblanc
Member
Registered: 2016-02-23
Post 39/49

Re: [Gen 1] Sound bug

I managed to induce the bug even on a retail ROM just by importing a battery file, continuing the game normally and defeating a trainer over and over until the bug happens and the victory music is glitched.

How is this possible? A save file contains data able to glitch the sound randomly? I have been using the same .sav file while making some last changes to the ROM.

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#5 2016-08-13 03:09:02

Ammako
Member
Registered: 2016-03-06
Post 42/90

Re: [Gen 1] Sound bug

You can do a loooooot of things with just a save file and a retail rom. :p
That being said, you haven't been able to get this bug to happen when using a save file created by retail rom yeah?


I get moody during that time of the month. You know, with the full moon and all.

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#6 2016-08-16 18:21:05

Montblanc
Member
Registered: 2016-02-23
Post 40/49

Re: [Gen 1] Sound bug

Nope, not even on a fresh save file of my ROM :)  Seems that something already fixed wrote anything in memory that continued affecting the sound engine.

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