Eli5 how does iPhone video recoded its own screen?! I’m baffled. Not much online about how it works either.


I know how to record the screen. But how does it actually work??

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When you look at the screen you’re seeing a display projection of icons, pics, etc. you interact with it, things happen with visual and auditory feed back.

When you video record the screen it’s just hooking into the display system and also writing it out as a video file which will show you the exact same screen interaction you saw earlier.

Then you can view it again at your leisure.

Anything you can see on your screen is handled by the internals of the phone like the processor and then projected onto the screen. The screen record app/feature simply makes a video of that projection while also projecting it onto the screen. There aren’t any cameras or anything involved. It’s all done on a software level.

Everything you see on a computer screen is rendered by a GPU aka Graphics Processing Unit aka a graphics card.
The commands that are sent to the GPU are recorded, then played back to you in a video format.
Essentially just keeps track of what is being displayed, then formats it into a video.


It records the screen the same way it displays stuff on the screen. There is software inside the phone that figures out what the screen should look like, and puts that binary pattern in the memory used by the screen hardware to light up the display. To record it, it just makes a copy into the video file of the binary pattern that’s going to the screen, it’s already done the hard part – computing what goes on the screen.