About NES black border on both sides of the screen(resolved)

[apple]

I played NES games, find black border on both sides of the screen, why?
Look:

[namair]

I think because the ratio of the original NES games are 4:3 .
You can change the option to play in fullscreen to make the black bar disappear if you like.

[apple]

I set 4:3 but find black border on both sides of the screen. How can I set it?

[namair]

It’s depends on your emulator, however you should see the video setting and choose FS: fast or Fullscreen: Fast ect…

[apple]

Can you give me see your set picture? I can know where can set it. thank you.

[namair]

This is from the emulator that i use

[apple]

ok,thankyou I resolved