The VideoLAN Forums

Is there any way to stop VLC to stretch itself to bigger window when starting video? I know user can make it smaller by dragging it from corners but that doesn't help that much when half a screen is off screen

VLC open the video at its given resolution. So if you're playing a 4k video on a 1920x1080 screen it will obviously be larger than the screen.

You can set a lower default zoom value but keep in mind it will be applied to any video:
Menu Tools -> Preferences (Show settings = ALL) -> Video
Then on the right panel scroll down to the Zoom Video option and set it to 0.5.
When done, save, exit and restart VLC for the new settings to work.

Another way is to hit Z to zoom in and Shift+Z to zoom out on the fly.

No 4K videos, juat Full HD and screen and tv are capable to play those (after resizing VLC so it's easier to drag to tv and see miniibar). Worked on older "VLC" too.

Related question: Is there way to stop resize on livestreams?