Signal Carnival | Hacker News Reader

Signal Carnival

quiss.org

141 pointsadunk19 comments

This was damn cool. Watching and listening to it I wonder what is the hardest. Producing video with a sound chip or producing audio with a video chip. Fun stuff.

After reading the article it's clear that the former is much more difficult, because video needs much higher bandwidths than the sound chips are designed to produce, and the hardware even contains extra hurdles like a bandpass that filters out higher frequencies even if you manage to hack the chip into producing them.

That's why the video basically happens in only one dimension instead of two.

I thought this would be a post about the messaging service and current politics in the US.

Much nicer! Very cool demo!

For others like me confused as to why there's not a video example on the page: click the youtube link in the first sentence!

Super cool mesmerizing effect.

https://www.youtube.com/watch?v=_Orvsms7Ils

I'd love to see (and hear) what happens if you send the same signal through both video and audio.

Probably not as nice as this demo, but I'm sure there must be some signal combinations that yield interesting results.

I... might have to try that. :)

That has been done, not on the C64 and raster CRT though. Search term "oscilloscope music".

What a beautiful thing to do

I’d like to see & hear the correctly plugged version of the video.

My first reaction too, but...

https://csdb.dk/release/?id=252090 plus a c64 emulator; it's a pretty similar experience to just watching colors flash on the screen while a game loads and decrunches...

I love the hack value, this is the kind of content I am here for!

has anybody tried this with a modern computer, can that get more horsepower out of audio-video?

The problem you'll almost immediately run into is that modern computers typically use digital video streams rather than analog streams. You'd need to use VGA for the audio part (and that's making a lot of assumptions about the ability to send arbitrary stuff on it, I'm not exactly sure these days), and I'm not sure what readily available component could even be used for the video part.

Sure, but there are slightly more modern systems that still had analog composite video and audio output which had a lot more power than a 6502-based C64 - like the 680x0-based Amiga. Also, other systems may not have had the C64's bandpass filter on the audio which induced the bluriness in this demo.

Right - unlikely this is going to work.

For sending a VGA signal even at 640x480 you will need a short h sync pulse of 3.8us at 31.x kHz. You would need an audio interface without filters with single low pulses at 260 kHz samplerate. Otherwise the monitor will just not detect a signal.

You could however use h sync and v sync from the VGA output and feed audio to the rgb channels. But thiswould give a mess of wires and is far from the beautiful idea shown here to just connect the white/yellow plugs differently.

I meant in the sense of getting one of those old 3.5mm-r/w rca adapters and plugging it into a modern thinkpad, phone or macbook, I’d assume anything taking digital signal by principal only wants frames of/approaching perfection

You can plug in any analog audio source into analog video (crt, video mixer). You can even mix audio + video using two resistors and have the music distort the video source. Another fun one is ‘no input mixing’ using a audio mixer (plug in output to input to get interesting feedback). Wonder if that would work with video mixers mmm

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