Also, yay for physical media!

“VideoNow used non-standard sized optical discs, apparently based on the audio Compact Disc format. These were known as Personal Video Discs (PVDs) and the discs for VideoNow were 85mm in diameter (compared to 120mm for a standard Compact Disc) with a capacity of up to 25 minutes of video. Only mono sound was available as the video information took up one of the audio channels.”

↑ Quoted from the link you are replying to.

MD always seemed like a great idea to me. It’s so stable, not susceptible to random magnetic corruption. The media is protected, unlike CD/DVD-RW. I always expected someone to push it for archival storage.

… it’s not a CD…. it’s a Blu Ray….. that’s the source of your confusion I’m guessing.

Yeah, I have HiMD discs and recorders. You can virtually put what you want on them. I managed to hook up a camera and record live images onto them.

Interesting claim of 25 minutes of video given 80mm cd only held 18 to maybe 24 minutes of audio depending on the format, or 210MB at most. If literally only using one audio channel for the video, the greyscale choice makes some sense but it would still be very poor quality or resolution. I imagine some form of VCD encoding was likely used given that was all the rage before DVD burners and media become more prevalent, reliable and affordable.