An interactive look at how a video signal is made

Re:An interactive look at how a video signal is made by rasz on Monday June 07, 2021 @11:52PM (#27430486)

Cool thing about analog video was the ability to cheaply store a Lot of data using common VHS deck. Japanese started recording Digital PCM on Video tapes in 1977, long before CDs. This is why CD audio has 44.1 sampling rate - common divisor for fitting 3 samples per line of video in both 50 and 60 field rates.

https://www.youtube.com/watch?v=DLS9sQUxVlI

https://youtu.be/-ZJmQQ9OCtI?t=7240

In 1992 enterprising Russian company released a line of ISA controllers turning VHS into a streamer https://en.wikipedia.org/wiki/ArVid up to 4GB per tape at the time 4GB hard drive cost over $1000.

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Re:An interactive look at how a video signal is made by s_gourichon on Tuesday June 08, 2021 @03:53PM (#27439942)

> This is why CD audio has 44.1 sampling rate - common divisor for fitting 3 samples per line of video in both 50 and 60 field rates.

Indeed. Naively multiplying the line frequency (15734Hz in NTSC, 15625 in PAL) by 3 doesn't fit, but if some room is made to make a really valid video signal, which implies 50 or 60 gaps per second, and some logic to play samples at correct point in time, then it fits.

Ref: https://en.m.wikipedia.org/wiki/44,100_Hz

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Re:An interactive look at how a video signal is made by seekbeak on Wednesday June 09, 2021 @01:41PM (#27450791)

Crazy. I’d always thought it was because of Nyquist and the 20k ish human hearing limit.

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