Amiga Genlock

[psxphill]

typically a genlock just takes amiga RGB and superimposes a composite input signal over it and you are getting color composite blend out the other end.

What everyone refers to as a genlock is actually a video mixer.
 
The Amiga chipset can synchronise it's output to an external video source, so the genlock is actually internal.

[psxphill]

I'm not sure this thread is oriented to the 7.14MHz CPU clock speed of the 68000 or why it was chosen.

I don't see anyone mentioning that before you, the original question was "What is an Amiga genlock?". And the answer is, it's a video mixer.

[psxphill]

This refers to the CPU being clocked so as to coordinate the video output for mixing, plus other uses. Or did you not know that is why the CPU runs at an "odd" speed?

The CPU clock speed isn't related to mixing. It's to make it easier/cheaper to share the chip ram between the 68000 and agnus.

[psxphill]

We all spent hundreds on genlocks back in the day, and if they were available directly on the computer, it would have been nirvana.

You were paying for the quality of the rgb decoding and encoding, that was the difference between the cheap and expensive amiga "genlocks".
 
An amiga "genlock" is made up of a slave sync generator & a video mixer.

[psxphill]

Dont know why you guys keep calling genlocks "video mixers" a video mixer and a genlock are 2 different devices. A Generator Lock just syncs the computer to the incoming video and allows for overlay, keying, or reverse overlay. A "video mixer" mixes more than 1 video source, sometimes with effects or transitions.

What is refered to as an amiga "genlock" provides the clock for the amiga chipset to genlock to and then mixes between the two based on the signal output by the amiga. It has no concept of overlay, keying or reverse overlay, thats all internal to the Amiga. The "genlock" then just mixes between the 2 video sources (amiga's output and the external video).
 
Granted the video mixer in the amiga "genlock" doesn't have all the functionality of vision mixers used in tv production. But effects and transistion generators aren't required to mix two video signals.
 
However a genlocking is only for synchronising, it has nothing to do with mixing any signals. You can genlock with only one video source, the sync can come from anything. It's common to genlock to GPS (http://www.dk-technologies.com/downloads/specs/PT8616.pdf)

[psxphill]

Gotta somewhat disagree here. The only thing internal to the Amiga is the ability to synchronize to external sync provided by the genlock. The actual overlay is done in the genlock.

Genlocking is something that the Amiga can do all by itself, it only is the process of synchronising to an external clock.
 
Just because someone used the word genlock when marketing an external peripheral doesn't change that. They could have called it a video thingy.
 
At which point you'd say that the video thingy plugs into the amiga and allows it to genlock to an external video signal and the video thingy then mixes between the amigas output and the external video signal, based on the signal generated by the amiga.
 
Nobody is going to call it a video thingy though, they are going to call it a genlock. So if someone (like the OP) asks "what is an amiga genlock?" the answer is: it's a video mixer and slave sync generator that allows the amiga to genlock to the external video source.
 
In the real word genlock is a verb, not a noun.
 
So equipment is genlocked if it's synchronised to an external clock.
Equipment genlocks to an external clock.
 
It's unlikely the incorrect usage of the word genlock is going to disappear, so I'm not going to keep arguing the point. You'll either be educated, or you won't. I can't do anymore