New PCM demo

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

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frantik
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New PCM demo

Post by frantik »

Here's a little demo using $4011 to play raw 7bit PCM data while simultaneously doing some graphics stuff and reading from the controller. This is my first demo so let me know what you think :)

Download demo
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blargg
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Post by blargg »

Hahaha, excellent. Wins on both counts.
Celius
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Post by Celius »

Wow! Amazing quality!! And pretty humorous, too :) .
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Dwedit
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Post by Dwedit »

When is the horizontally flipped image used?
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frantik
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Post by frantik »

it's not used.. i just wanted to put something in the other pattern table for nosy folks lol ;)


glad u guys enjoyed it :D :D
Roth
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Post by Roth »

D'oh! You got me! haha Pretty nice demo : D
WedNESday
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Post by WedNESday »

Aw shame, I've just tested it out on WedNESday, but there's no sound emulation at the moment...
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blargg
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Post by blargg »

No sound? Then you were half-spared :)
strat
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Post by strat »

Woah - I didn't know the NES could play anything other than bloop bloop bloop.
smkd
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Post by smkd »

cool demo. i thought about 4011 streaming with other tasks crammed in between a little while back, you get a decent chunk of time with 8khz or 16khz between 4011 writes. i thought about using irq to time between 4011 but then i remembered ppu address lines aren't active in nmi so that wouldn't work out too well.

eventually i'd like to write a pcm streamer but i'd also want it doing something in the background otherwise it's pretty unremarkable. i co-authored something similar for the snes, was pretty fun to make.
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koitsu
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Post by koitsu »

Haha, awesome. The audio quality is downright scary.
tepples
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Post by tepples »

strat wrote:I didn't know the NES could play anything other than bloop bloop bloop.
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Good job! Go again.

I wonder how much the quality would suffer under ADPCM.
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Hamtaro126
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Post by Hamtaro126 »

Can Frantik release source code for the NES Demo? And can SMKDan do the same with the SNES Demo? Because the Sound/Music is nice and I'd like them to be released.
frantik
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Post by frantik »

tepples wrote:I wonder how much the quality would suffer under ADPCM.
haha I actually got the idea from you musing about the same thing a year ago

It would be interesting to hear using ADPCM compression.. but would you have enough time to decompress it and play the audio in addition to doing everything else? The audio is playing back around 14.5 kHz and there are only 16 clock cycles left between each sample.

one cool thing I discovered is you can get away with using more clock cycles if you only do it once in a while.. like you can do a fair amount of work during vblank and the distortion isn't noticeable until you've wasted a lot of clock cycles.
strat
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Post by strat »

"Haha, awesome. The audio quality is downright scary."

Honestly, that sounds at least as good as vinyl.

Thanks for the Big Bird vid, Tepples
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