Codemasters Roms, Everdrive N8 and a PAL NES.

Discuss technical or other issues relating to programming the Nintendo Entertainment System, Famicom, or compatible systems.

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rainwarrior
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Re: Codemasters Roms, Everdrive N8 and a PAL NES.

Post by rainwarrior » Sat Feb 11, 2017 9:27 pm

Here's some advice on how to edit NES file header: viewtopic.php?p=188871#p188871

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TR3KT
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Re: Codemasters Roms, Everdrive N8 and a PAL NES.

Post by TR3KT » Wed Mar 01, 2017 4:31 am

Sorry to bump this for anyone tied the the thread, but i've come across another weird quirk in codemasters games. When the intro plays, after the sound effect plays when 'Absolutely Brilliant!' pops up at the bottom you can hear popping and static in the background. I assumed it was my NES's PSU buzz chiming in conveniently. But it's happening in emulators as well and only during the codemasters intro after the ringing sound effect. Is it caused by some accidental writes to the APU or something?

Games i tested for:

- Micro Machines (Aladdin)
- Micro Machines (Fixed mapper)
- Micro Machines (U) (emulated)
- Ultimate Stuntman (U) (Real PAL hardware and emulator)
- Bee 52 (U) (everything)
- Cosmic Spacehead (PAL)
- And a couple of others that i have on my Everdrive but forgot the name to

You get the point. I think this weird buzzing/popping is in every codemasters game released.

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mikejmoffitt
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Re: Codemasters Roms, Everdrive N8 and a PAL NES.

Post by mikejmoffitt » Wed Mar 01, 2017 10:45 am

I believe most if not all codemasters games reset the phase in vblank, so you get a buzz equal to your vertical refresh in frequency.

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Re: Codemasters Roms, Everdrive N8 and a PAL NES.

Post by Dwedit » Wed Mar 01, 2017 11:54 am

The intro sound engine and in-game sound engines are not the same. Some of the codemasters games have the reset phase every frame issues, others do not.
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Re: Codemasters Roms, Everdrive N8 and a PAL NES.

Post by Bavi_H » Wed Mar 01, 2017 8:01 pm

TR3KT wrote:i've come across another weird quirk in codemasters games. When the intro plays, after the sound effect plays when 'Absolutely Brilliant!' pops up at the bottom you can hear popping and static in the background. [...] Is it caused by some accidental writes to the APU or something?
FCEUX's SoundDisplay.lua shows the noise channel "pitch" and "mode" values continue changing without starting a new note, so I guess that's what's causing the faint static sound.

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TR3KT
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Re: Codemasters Roms, Everdrive N8 and a PAL NES.

Post by TR3KT » Thu Mar 02, 2017 5:08 am

Interesting, i heard somewhere on this board that the awful 60hz buzz in 'Dizzy the adventurer' is caused by the same issues. Are there games developed by other companies that program the sound engine in a similar fashion cause the same static noises where silence is supposed to be?

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Re: Codemasters Roms, Everdrive N8 and a PAL NES.

Post by Dwedit » Thu Mar 02, 2017 8:56 am

I've only seen it in Dizzy The Adventurer, and the unreleased other Dizzy game.

Homebrew rom Stars SE had a similar problem, it reset the phase every time the frequency changed, messing with vibrato effects. (Sorry Chris Covell, I know I keep pointing out bugs in this rom all the time.)
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rainwarrior
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Re: Codemasters Roms, Everdrive N8 and a PAL NES.

Post by rainwarrior » Thu Mar 02, 2017 9:16 am

The startup buzz is on the noise channel.

Every frame it writes $400C twice, once with volume 5, then with volume 0, 44 cycles later.

Thus, it creates a very short burst of noise (44 cycles is slightly longer than 1 sample at 44100 Hz) once per frame.

I think emulators might amplify the problem slightly due to the difficulty of filtering out this kind of high frequency effect. (Plus it really stands out against the lack of baseline noise.)

fiosbor
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Re: Codemasters Roms, Everdrive N8 and a PAL NES.

Post by fiosbor » Tue Sep 26, 2017 1:01 am

rainwarrior wrote:Here's some advice Phen375 on how to edit NES file header: viewtopic.php?p=188871#p188871
not open this link viewtopic.php?p=188871#p188871

can u healp me ?
Last edited by fiosbor on Tue Oct 03, 2017 10:20 am, edited 1 time in total.

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Re: Codemasters Roms, Everdrive N8 and a PAL NES.

Post by tepples » Tue Sep 26, 2017 6:13 am

What error message do you get when the link does "not open"?

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