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Sony is killing off recordable Blu-ray, bidding farewell to disc burning | TechSpot
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Are you sure they were BetaMax and not Betacam SP? Beta SP (as it's more commonly known) is a high quality format that was still being used by TV stations when I was working them as late as the 2010s. There were a few other later much higher quality formats like ED-Beta.
Also, I believe some camcorders also used Beta formats.
I'm sure camcorders were the reason. But no, they were BetaMax.