Gain = ISO in digital video?

[GM_of_OLC]

My friend has an XL2, and I'm trying to understand the exposure relationship. In photography, we have the aperture, shutter speed, and ISO.
In digital video, they have aperture, shutter speed, and.... gain?
Or is gain more like exposure compensation? But they have an exposure compensation dial too.
I'm confused.
Anybody?

[LORAC]

Gain is like ISO - more gain = more noise. I try to keep gain to max 9db. Exposure = Iris. 2.8 = narrow depth of focus. f5.6 is optimum.

[darosk]

ISO is to still camera as gain is to video camera.

[Trey T]

gain is the scientific term and the correct term for imaging chips like CMOS, i.e.

ISO is just a layman's term, they just use it to keep the terminology the same as film. not even sure if canon and nikon has the same standard but that's another story.

exposure compensation works on semi-auto shooting for both camcorder and dslr, if I remember correctly. I think it's more of the adjustment after the sensor captures image(s) by the software. on other hand, gain is physically what the sensor is adjusting its power to produce more or less sensitivity. the more power you put into the sensor, the signal-to-noise ratio will increase.

gain- hardware related
exposure compensation- software related.

not sure if that is totally correct but....