State and action timing

[Lina]

Hey,

there are some essential concepts in VizDooms which I havn't understood yet. Mainly it's about the timing of the game. I am using ViZDoom in spectator mode. To perform an action I use the game.advance_action() method with default skiprate of 1 and update state set to True. I noticed that each state last 4 tics, sometimes 3, sometimes 5. What causes this unstability?
Also one button press (eg. move left) doen't corrrespond to the same number of pixels each time. I figured that there is some kind of delay and acceleration. Still I don't know how this is coded. There must be a function which maps a button press to movement in terms of pixels, i guess. It just that I couldn't find this function in the skipt so far.
Hope anybody can help me with this questions.