BlixTerm Brings Full-Speed YouTube Video To The Commodore PET

ByPhyllis R. Edwards

Jul 2, 2022 , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,


If you have at any time made use of a dwelling computer from the late 1970s or early 1980s, you will no question be familiar with the slow pace of their consumer interfaces. Even listing the contents of a Essential software from RAM could take various seconds, with the display screen updating just one line at a time. Video clip games were entirely optimized for pace, but could continue to cope with just a handful of little by little-moving objects at the very same time. Clearly, enjoying anything resembling whole-movement video clip on hardware from that era would be completely impossible – or so you could possibly feel.

In fact, [Thorbjörn Jemander] has managed to persuade a Commodore PET to engage in YouTube movies at a absolutely sensible 30 frames for each next. He describes the course of action of creating the “BlixTerm” hardware and computer software in his video (embedded underneath), together with a lot of practical facts on how to push digital devices to their complete boundaries.

A video of a drifting car, as rendered by a Commodore PET displayObviously, the PET demands a little bit of aid from modern-day hardware, in this scenario a Raspberry Pi Zero 2 W hooked up to the “User” growth port. The Pi connects to YouTube via WiFi and hundreds the asked for online video, then downconverts it to a 640×200 grayscale stream and transforms each and every body to an 80×25 grid of people, applying individuals from the PET’s ROM that most carefully resemble the sample essential.

While it took really some effort to squeeze adequate efficiency out of the Pi to do all of this in real time, the trickiest bit was acquiring the resulting character stream into the PET’s movie memory rapidly sufficient. To do this, [Thorbjörn] designed a special interface card with 2 KB of twin-port SRAM, which enabled the Pi to retailer its video frames as before long as they were being all set on one particular facet, and the PET to load them at its personal rate from the other side. With just sixteen microseconds accessible to process each and every byte, the PET’s CPU can execute only 4 or five device code instructions scarcely adequate to load and shop a one character and soar to the future memory address.

The close result, as you can see in the movie, is actually remarkable. Even within the constraints of the Commodore character established, the resulting picture is evidently recognizable, although the frame amount appears to defy the hardware’s limitations.

If you are a Commodore aficionado and wondering what the hell that odd PET 600 model is all about, [Thorbjörn] designed a online video about that too it’s a rebadged 8296 aimed at the Swedish market place. We have actually seen a job to deliver reside video clip on the PET just before, even though at a significantly reduce frame fee. Many thanks for the idea, [Keith Olson]!


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