The first Laserdisc Player

[MIPS]

I was looking at my stash of players last night and started to wonder what exactly was the first laserdisc player to hit the market. Google is oddly not giving a straight answer.

It states that the Magnavox Magnavision VH-8000 was the first consumer player available on the market starting in 1978. The second was apparently the Pioneer VP-1000.
The first industrial model player is the MCA DiscoVision PR-7820 and it too was marketed (in bulk quantity only) starting in 1978. The second was apparently the Pioneer LD-1100.

I cannot seem to find any information of any Laserdisc/DiscoVision players existing in the market before 1978, so was the 8000 and the 7820 both hitting the market at the same time or did one officially become available before the other and thus was "the first" laserdisc player?