Sound 00 corruption: Difference between revisions

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(Created page with "'''Sound 00 corruption''' is a glitch effect which happens whenever the game tries to play sound 00. It can be caused by glitch textboxes which play sound 00, or enabled with expanded inventory by changing item 31 quantity (wMapMusicSoundID; D35B in Red/Blue and D35A in Yellow) and getting on then dismounting the Bicycle (however the Bicycle method does not work for bank 1F, as the game will keep playing the Bicycle music). This effect was documented by TheZZAZZGlitc...")
 
m (Added hex markers and tweaked some words.)
 
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[[File:Sound 00 corruption.png|thumb|right|200px|Sub-tiles 01 and 43 on the screen, from the corruption of $C414.]]
'''Sound 00 corruption''' is a glitch effect which happens whenever the game tries to play sound 00. It can be caused by glitch textboxes which play sound 00, or enabled with [[expanded inventory]] by changing item 31 quantity (wMapMusicSoundID; D35B in Red/Blue and D35A in Yellow) and getting on then dismounting the Bicycle (however the Bicycle method does not work for bank 1F, as the game will keep playing the Bicycle music). This effect was documented by TheZZAZZGlitch who documented its $C414 corruption via glitch text boxes, and expanded on by FutureFractal in the GCRI Discord.
'''Sound 00 corruption''' is a glitch effect which happens whenever the game tries to play sound 00. It can be caused by glitch textboxes which play sound 00 while the game is on bank $02 (many overworld maps and indoor maps other than caves) or bank $08 (in battle), or enabled with [[expanded inventory]] by changing item 31 quantity (<code>wMapMusicSoundID</code>; $D35B in Red/Blue and $D35A in Yellow) and getting on then dismounting the Bicycle (however the Bicycle method does not work for bank $1F, as the game will keep playing the Bicycle music). This effect was documented by TheZZAZZGlitch who elaborated on glitch text boxes and the $C414 corruption, and expanded on by FutureFractal in the GCRI Discord.


Some similar effects occur for sound bank $20. In non-Japanese versions of Pokémon Yellow (at least the English version), this is the sound bank where the Pikachu's Beach minigame, printer error, Jessie & James encounter, Yellow unused track music is located.
==Effects==

⚫
*$C024, $C214, $C414, and $C614 are corrupted
==Effects (English versions)==
⚫
**$C024 becomes FFFF and is the stored return address for sound channel 8, so playing sound ID 00 with channel 8 active may cause a freeze.
===Sound banks $02, $08===
⚫
**$C214 represents the coordinates of the first NPC in the map. It is corrupted to y=253 (0xFD) and x=66 (0x42). This is far out of bounds, so the NPC will appear to disappear unless the player walks to that location while avoiding map connections (possible by changing wYCoord (item 34 quantity; D361/D360) and wXCoord (item 35 quantity; D362/D361) in the expanded inventory.
⚫
*Two-byte words at $C024, $C214, $C414, and $C614 are corrupted.
⚫
**$C414 becomes 0143, causing sub-tiles 01 and 43 to appear when a text box or the start menu is open.
⚫
**$C024 becomes "FF FF" and is the stored return address for sound channel 8, so playing sound ID 00 with channel 8 active may cause a freeze.
⚫
**C614 is in wTileMapBackup and is corrupted to 05 43, but no effect seems to be visual.
⚫
**$C214 represents the coordinates of the first NPC in the map. It is corrupted to y=253 (0xFD) and x=66 (0x42). This is far out of bounds, so the NPC will appear to disappear unless the player walks to that location while avoiding map connections (possible by changing <code>wYCoord</code> (item 34 quantity; $D361/$D360) and <code>wXCoord</code> (item 35 quantity; $D362/$D361) in the expanded inventory.
⚫
**$C414 becomes "01 43", causing sub-tiles 0x01 and 0x43 to appear when a text box or the start menu is open.
⚫
**$C614 is in wTileMapBackup and is corrupted to "05 43", but no effect seems to be visible.

===Sound bank $1F===
The above effects seemingly do not occur.

===Sound bank $20===
For Pokémon Yellow (as sound bank $20 is invalid in Pokémon Red and Blue), using the Bicycle method and adjusting item 32 (<code>wMapMusicROMBank</code>; $D35B) to 0x20 will cause the following effects.

*$C024 becomes "FF FF" as before.
*$C214 becomes x=65 (0x41) and y=236 (0xEC).
*$C414 becomes "F0 41", causing sub-tiles 0xF0 and 0x41 to appear when a text box or the start menu is open.
*$C614 is in wTileMapBackup and is corrupted to "F4 41", but no effect seems to be visible.

{{clr}}


==Cause==
==Cause==
According to FutureFractal, this corruption is because the channel value for sound 00 is FF; the game erroneously writes to $C024, $C214, $C414, and $C614 as if they were channel playback pointers.
According to FutureFractal, this corruption is because the channel value for sound 00 is 0xFF; the game erroneously writes to $C024, $C214, $C414, and $C614 as if they were channel playback pointers.


==YouTube video==
==YouTube video==
{{YouTube|E-CQS5B2sjY|TheZZAZZGlitch}}
{{YouTube|E-CQS5B2sjY|TheZZAZZGlitch}}
==See also==
*[[Glitch sound bank]]
{{Stub}}
{{Stub}}
[[Category:Glitch effects]]
[[Category:Glitch effects]]

Latest revision as of 05:05, 3 January 2023

Sub-tiles 01 and 43 on the screen, from the corruption of $C414.

Sound 00 corruption is a glitch effect which happens whenever the game tries to play sound 00. It can be caused by glitch textboxes which play sound 00 while the game is on bank $02 (many overworld maps and indoor maps other than caves) or bank $08 (in battle), or enabled with expanded inventory by changing item 31 quantity (wMapMusicSoundID; $D35B in Red/Blue and $D35A in Yellow) and getting on then dismounting the Bicycle (however the Bicycle method does not work for bank $1F, as the game will keep playing the Bicycle music). This effect was documented by TheZZAZZGlitch who elaborated on glitch text boxes and the $C414 corruption, and expanded on by FutureFractal in the GCRI Discord.

Some similar effects occur for sound bank $20. In non-Japanese versions of Pokémon Yellow (at least the English version), this is the sound bank where the Pikachu's Beach minigame, printer error, Jessie & James encounter, Yellow unused track music is located.

Effects (English versions)

Sound banks $02, $08

  • Two-byte words at $C024, $C214, $C414, and $C614 are corrupted.
    • $C024 becomes "FF FF" and is the stored return address for sound channel 8, so playing sound ID 00 with channel 8 active may cause a freeze.
    • $C214 represents the coordinates of the first NPC in the map. It is corrupted to y=253 (0xFD) and x=66 (0x42). This is far out of bounds, so the NPC will appear to disappear unless the player walks to that location while avoiding map connections (possible by changing wYCoord (item 34 quantity; $D361/$D360) and wXCoord (item 35 quantity; $D362/$D361) in the expanded inventory.
    • $C414 becomes "01 43", causing sub-tiles 0x01 and 0x43 to appear when a text box or the start menu is open.
    • $C614 is in wTileMapBackup and is corrupted to "05 43", but no effect seems to be visible.

Sound bank $1F

The above effects seemingly do not occur.

Sound bank $20

For Pokémon Yellow (as sound bank $20 is invalid in Pokémon Red and Blue), using the Bicycle method and adjusting item 32 (wMapMusicROMBank; $D35B) to 0x20 will cause the following effects.

  • $C024 becomes "FF FF" as before.
  • $C214 becomes x=65 (0x41) and y=236 (0xEC).
  • $C414 becomes "F0 41", causing sub-tiles 0xF0 and 0x41 to appear when a text box or the start menu is open.
  • $C614 is in wTileMapBackup and is corrupted to "F4 41", but no effect seems to be visible.


Cause

According to FutureFractal, this corruption is because the channel value for sound 00 is 0xFF; the game erroneously writes to $C024, $C214, $C414, and $C614 as if they were channel playback pointers.

YouTube video

YouTube video by TheZZAZZGlitch

See also

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