Acmlm's Board - I2 Archive - Rom Hacking - PCM Sounds in NES Games
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Vystrix Nexoth
Posts: 81/348 |
ROM
Source
(the source is not compilable because the raw sound data file has not been uploaded).
this is, like, two seconds of 8000Hz, 7-bit, Mono PCM audio. I think the pAPU can handle up to a little under 16000Hz; I didn't try it, though. |
Geiger
Posts: 32/460 |
While its probably completely possible to replace the PCM sounds, its unlikely that you'll get better sound quality. Remember that the entire ROM for some NES games is only about 16k. Far too little room for good sound bytes.
---Evil Peer |
BMF98567
Posts: 56/1261 |
It really depends on what kind of samples the game uses. Most are 1-bit delta modulation, which AFAIK is a pain in the you-know-where to replace, because it's obviously not a standard sound format; I have seen tools that encode/decode the data, though. Other games (though this is rather uncommon) stream raw waveform data straight into the chip; you can usually open these games in a sound editor and listen to the samples (The Three Stooges and the Teenage Mutant Ninja Turtles demo ROM, for example). In these games, you could probably just cut and paste a sound clip directly into the file. |
Gavin
Posts: 6/799 |
well, Damian Yerrick has got some really cool stuff. He's got source to all his projects, but your going to have a hella hard time deciphering it i'm guessing  It's in his newest game that he reads a sound effect from a .wav file: Tetramnio, a tetris-like game. linkage: http://www.pineight.com/nes/
i'm fairly certain VN has experimented with it as well, or at least maybe he had an example of someone else experimenting with it..
but in short, yes it most certainly is possible. i'd say it's not a beginners programming project by any means..
but for your futher research:
http://gavin.panicus.org/downloads/dmc.txt
i really wish i could help you more.. in fact, i know i at one point had a copy of a PCM test that VN made a long while ago, i have the .ASM file and the .NES file still, but i'm missin the main component..the .raw file that has the sound to compile  . besides, i never asked him if i could hand it out..
you're best bet is to ask him. sorry
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drjayphd
Posts: 61/1477 |
Ever play an NES game with samples and think "holy crap, that doesn't even SOUND like what it should be"? No? Go download NES Play Action Football, get a first down, and then you will. Anyway, I'm wondering if anyone has any ideas about how I could replace samples in NES games... I'm referring to the PCM channel in particular. I'm sure there's no one way to do it in every game, but if anyone has any ideas as to registers and such... Going off of the name, it sounds like I could possibly use a WAV file to replace the sample, because that's also PCM audio too, no? |
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hukka
