Signal Carnival

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