Halui inputs - speed vs velocity

I am confused about the function of the following halui inputs:
halui.jog-speed (float, in) - pin for setting jog speed for minus/plus jogging
halui.jog.<n>.analog (float, in) - analog velocity input for jogging (useful with joysticks or other analog devices)

What is the difference, I thought speed and velocity are the same thing.

I want to create a configuration that uses the proportional output of a game pad to proportionately control the speed of a jog. ie The further I push on the control the faster the jog. I can't find detailed information on input level versus output speed and/or velocity.

The jog speed sets the speed of jog when another jog pin is set.
The analog pin causes a jog at that speed whenever that particular pin is non-zero.

The analog one is what you want to connect to the gamepad.
Have you seen: wiki.linuxcnc.org/cgi-bin/wiki.pl?Simple_Remote_Pendant ?
That sets up a game-pad to jog at 3 fixed speeds depending on what combination of back-buttons are pressed.
(I had mine set up that way and liked it)

If you prefer analog jogging then I think that it is covered here:
wiki.linuxcnc.org/cgi-bin/wiki.pl?Adding...imple_Remote_Pendant
But that is also massively complicated (much more so than necessary just to have analog jog)