Terrible quality when recording in 1920x1080 while playing in 3840x2160

[lolhedy]

Hi, I play league of legends with a 3840x2160 resolution (borderless) however, I'd like to record video in 1920x1080. So far I've tried to do so by setting the Base Canvas Resolution to 3840x2160 and the Output Scaled Resolution to 1920x1080, the problem is that the quality is terrible, to the point where it's even hard to read the in-game chat.

I've tried changing the settings but the result is always the same unless I choose to produce 3840x2160 raw recordings.
Could anyone please tell me why this happen and how to solve this problem? Below are my pc specs:

CPU
Intel Core i7 9700F @ 3.00GHz
GPU
MSI GeForce GTX 1080 Armor 8G Oc Graphic Card, Interface PCIe 3.0, 8 GB GDDR5X, 256bit, 2560 Cuda Cores
RAM
Corsair Vengeance 32GB DDR4, 3200 MHz, CL16

I also tried using other recording software but the problem remains.

Thank you in advance for your kind help!

 

[koala]

Any type of rescaling will make details fuzzy. Even downscaling. If you downscale from 3840x2160 to 1920x1080, you quarter the amount of pixels. The rescaling alone removes 3/4 of all detail. You merge every 4 pixels into one pixel. If some chat text is 20 pixels wide in the game, it is downscaled to 20/4 = 5 pixels, which probably looks like a fuzzy mess.

To get a proper 1920x1080 downscaled version of a 3840x2160 source, you need to increase the UI elements of the game, so they are still big enough after downscaling.

 

[lolhedy]

Hi, thanks a lot for making me understand what was the problem!
I've done several tests, I found out that If I put windows screen resolution to FHD, the game itself to FHD (fullscreen mode), then I can record at FHD without needing to rescale. It doesn't look particularly good in-game but when I upload the video on youtube it looks pretty good.
However, I've noticed that if I change the windows screen resolution and put it to 4k, without touching the other variables the video quality is still pretty bad when uploaded to youtube.

Could anyone explain to me why? I'd like to know if there's a way to solve this because using a 4k screen set to FHD seems to be very painful...