This is A Mind Is Born, a demo of the Commodore 64 going haywire. It won first place at the Oldskool 4K Intro competition at last week's Revision 2017 event, and it's easy to see why.
Amazingly, the 2:21-long video comprises no more than 256 bytes, and uses the retro-mystical prowess of the Commodore 64, an 8-bit computer that first debuted in 1982, to deliver a pulsing glitch music video thanks to the smart programming of its creator, Linus Åkesson. As he explains in a post detailing the work behind the demo, it can all sound a bit technical. I'm not going to pretend that I understand BASIC or PETSCII characters, but the idea is as follows,
The demo is driven by its soundtrack, so in order to understand what the program needs to do, it helps to have a schematic overview of the various parts of the song.
The three voices of the SID chip are used as follows: Voice 1 is responsible for the kick drum and bass, Voice 2 plays the melody and Voice 3 plays a drone that ducks on all beats, mimicking the genre-typical side-chain compression effect.
All in all, the song contains 64 bars in 4/4 time. It is played back at 112.5 bpm by means of a 60 Hz timer interrupt. The interrupt handler is primarily responsible for music playback, while the visuals are mostly generated in main conext.
Demos are short, autonomous programs that lead to interesting visual or auditory effects. There's nothing pre-rendered about them, in other words, just programs playing out that produce weird visualisations as a byproduct. There's an entire internet subculture around them, with a thriving demoscene that hosts events and competitions around the world.
There are plenty of beautiful and entrancing openings that call back to the sounds and styles of old technology, like the opening of Halt and Catch Fire, for instance. But where those performances are baked into an easy-to-use format distinct from the tools and hardware that originally created them, demos are a more intimate form of computer art, less like producing a series of cars in a factory warehouse and sending them to the dealer lot than hot-wiring one and transforming it in real-time.
You can find more of the winners, and the demos they created, here.