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In regards to the GoodNES3.14 ROMS:

Mortal Kombat Special (Pirate).7z <Mortal Kombat II Special (Unl) [!].nes>
Mortal Kombat Special (Pirate).7z <Mortal Kombat III Special (Unl) [!].nes>

The title screen appears to jitter in Nintendulator and Nestopia:



This does not happen in FCEUX and Mesen.

I'm not sure if this is just a buggy unlicensed game or if this is a real issue. Does anyone know if the issue appear on real hardware?

Interestingly, there are other pirate Mortal Kombat ROMs with similar title screens (e.g. Mortal Kombat 3 - Special 56 Peoples (Unl) [!].nes) that do not jitter in emulation.

Never trust FCEUX when it comes to raster effects, it's terribly inaccurate in that department. Several settings appear to be rounded to the nearest scanline, instead of taking effect immediately.

No problems in RockNES. Hmm... I guess...

a) Race condition in $2006 described before;
b) My emulator is inaccurate. No, it isn't.

As far as I can tell, Mesen does also jitter if you press start to reach the title screen faster.
If you wait out the entire animation sequence until the title screen, it doesn't jitter.

I'm fairly certain I did the JY Company emulation based on the info on the wiki (I just checked FCEUX, Nestopia and puNES and their code doesn't look very similar to mine).
I'd assume it's either a buggy game or that the JY Company mapper information isn't perfectly accurate (which seems likely considering how complex it is for a bootleg mapper)

I would second what tokumaru said, too - raster effects on FCEUX aren't very accurate (esp. if you're using the old ppu, which is the default option)

puNES also experiences the title screen jitters. But, I was unable to reproduce them in Mesen when pressing Start. Real hardware could resolve this mystery.

I have had that game on cartridge and I recall that it was hardware dependent, on some machines it didn't jitter at all while it did on others to varying degrees. I would imagine analog factors come in like on MMC3 carts which condition the address line for IRQ count.

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Nestopia Ntsc jitters
but PAL not Jiters.

Nestopia to Timer::A12<A12,8,2> a12;
is not jitters

Read that and thought I'd tell what I see on my AV Famicom since I own the cartridge. It's perfectly static. There's a tiny white line buzzing on the top left edge, nothing else.