Question / Help Monitor 34 2560x1080 (21:9) need help!

[landelord]

I ask for help, I just can’t adjust the output of my monitor to tweak so that the viewers are in full screen. It turns out that only in the middle of the picture and above and below the black bars.

Please tell me, can such a monitor make a full-screen output for viewers and how to do it?
already covered all the guides did not find anything

 

[koala]

You get black bars, because the aspect ratio of your app running full screen is 21:9, while the aspect ratio of the usual web-based video players (and of 95% of to monitors of your viewers) is 16:9. To avoid this, your app must run with an aspect ratio of 16:9 as well. For this, you cannot use your monitor fullscreen - you need to set the resolution of your app to some 16:9 aspect ratio resolution such as 1920x1080.