
Originally Posted by
NaitorStudios
If you say so... But I work with video editing and visual effects for 15 years and I'm also currently making extensions.
A screen recorder works by taking 24-60 screenshots per second and combining these in a video file, there's two ways it can go:
- Uncompressed (huge file sizes, low CPU/GPU usage)
- Compressed (intensive CPU/GPU usage during recording)
Usually the mobile screen recorders goes for uncompressed, sometimes it compress it after recording, which can take some time.
On Windows, most will use dedicated hardware for compressing, either from the GPU (Eg. Nvenc) or CPU (Eg. Quick Sync), hence why it's fast but still can affect performance.
But it all depends on your core count and how it's distributed, some games like Fusion one's will use a single core, leaving a ton of cores for recording (but still, if you don't allocate it for the softwares specifically it can affect).
Fusion games are usually lightweight if you program it well, but try setting your fps to 1000, uncheck Vsync and turn on a recorder to see how much your max fps will decrease.
You usually don't see the fps drop cause if the drop still above 60 you won't ever see it unless you unlock your fps, but I see many users struggling to keep 60 fps even on high end computers, those wouldn't handle screen recording.
About the camera thing, as far as I know, the device must support the usage on both cameras through software and hardware, they don't do it not cause they think it's a 'dumb idea', it's because they can't.
Hence why many high end devices have it in their built-in camera apps, cause these can handle it.
For this very exact reason you can't use the flashlight while using the camera if not from the camera app itself.
If you really want to check this out, I suggest hiring a mobile ext-dev, it can be quite expensive and results may not live up to expectations.
Cause any programmer that knows how this works wouldn't even try to do something that would cripple the performance...
Technically you could do the uncompressed one yourself by taking tons of screenshots and then playing it back, of course would be better to transform it to a proper video format but that would require a extension as well.
(Spoiler: I get 14 fps on my Galaxy S21 Ultra while doing this)