system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does a phone camera flash twice before actually taking the picture?
gpt
> When you press the shutter release, aTTL flash will fire a pre-flash before the actual shot, the camera will then measure the pre-flash with the ambient light level to calculate the power needed in the actual flash for the shot. 

Basically what you're seeing is a preflash. The camera uses that to measure how much power the actual flash requires.