The assumption that the content of the video had something do do with why it was broadcast may not be reasonable. Someone wanting to play the technical prank might well find some of the most random shit available to broadcast, hoping (perhaps mistakenly) that the point would be clear anyway.
I think its also possible that the the technically equipped people who did this were perhaps not thinking as clearly as usual that evening. Intoxicants may have been involved. There were some gifted organic chemists working out in the suburbs then.
> The assumption that the content of the video had something do do with why it was broadcast may not be reasonable
Well, the broadcasted video mentioned the name of one of the news anchors on one of the affected channels, and the first broadcast attempt even interrupted that channel's news show. So I think the video was made specifically for this hack. It's not like there was a YouTube for them to go to and search for weird shit on.
Just to contradict myself and add more fog to the thoroughly befuddled mass of theories on this incident, I will offer another.
Say some folks of mischievous "hacker" bent, having stumbled upon a forgotten "home video" grade tape containing moments of such transcendent perfection as these, decided they were obligated to share
them with the world. (This theory shares the same "intoxicants may have been involved" bit as the previous one i posted)
The principle of "a clipboard and a confident manner will get you anywhere" might well have gotten someone into two different rooms on that evening where they might have had a moment to sit down with a VCR and some vulnerable interconnect cables, before packing their big duffel bag back up and leaving quietly.
i believe there were cuts in the video so it was prerecorded. cuts that apparently were so clean it was another piece of evidence they had some access to some professional equipment as consumer grade equipment of the time wasn't up to the task
At that time, printers already printed yellow dots with the serial ID. I’m most surprised VHS wasn’t watermarked. It could have helped a lot in terrorist investigations (ransom videos).
I’m always afraid when I hear someone copypasting Apple memos. Obviously they must have watermark, if not text glyphs (rn = m, and further UTF-8 incantations), at least subtly different phrasing depending on which department, or person, views it.
VHS was pretty mediocre. Any watermarking inside the signal would have been noticeable or destroyed in transmission.
However it's true that the top invisible scanlines normally used for Teletext could have been used for this. My VCR did record them, I was surprised to be able to view Teletext pages at the time of recording, though they were full of distortion.
It would have been possible to filter that out though.
I think at the time VHS recorders were still mostly analog and would have been recognisable from their artifacts the same way a typewriter can be identified once found.
A VCR isn't like most other forms of visual recording media where it takes an image and records it in some other format to be converted back to an image later, it's actually a 1-to-1 analogue recording of the broadcast signal (minus any degradation from being an analogue copy). So by design it includes any tricks they used to include metadata in the normal broadcast signal.
The mechanics of how they worked are actually pretty interesting, I highly recommend Technology Connections' video on the subject [1], as well as the one on closed-captioning [2] (and his series on analogue TV in general [3])
> At that time, printers already printed yellow dots with the serial ID.
No schools in 1987 had color laser printers with this technology (and I doubt many businesses did either). Any students trying to do something fishy would have had to make do with, at best, 24-pin dot matrix printers with color ribbons.
I think its also possible that the the technically equipped people who did this were perhaps not thinking as clearly as usual that evening. Intoxicants may have been involved. There were some gifted organic chemists working out in the suburbs then.