YT Ultrawide Fill

For 21:9/32:9 monitors: fills your ultrawide screen with letterboxed YouTube video in fullscreen. No effect on 16:9.

Watch ultrawide videos the way they were meant to be seen. REQUIRES AN ULTRAWIDE DISPLAY (21:9 or 32:9) This extension zooms letterboxed video to fill your screen's extra width. A standard 16:9 or 16:10 display has no extra width to fill, so on those screens it intentionally does nothing at all. The toggle will tell you so on screen. Some YouTube videos are shot in 21:9 (cinematic ultrawide) but uploaded inside a 16:9 frame, so they arrive with black bars baked into the picture. On a 21:9 monitor that means bars on all four sides and a tiny image. YT Ultrawide Fill fixes that automatically. In fullscreen, it measures the real content aspect ratio of the video and zooms it so the picture fills the width of your ultrawide display, with no stretching and no cropping of actual content. HOW IT WORKS • Detects black bars by sampling video frames, then compares the true content ratio to your screen's ratio. • Zooms only when it helps: letterboxed 21:9 content fills the screen, while genuine 16:9 videos are left untouched. • The zoom is a uniform scale, so the image is never distorted, and real picture is never cropped. If filling the screen would cut into the image, it leaves the video alone instead. CONTROLS • A toggle button in the player's control bar (and the Shift+Z shortcut) switches Ultrawide Fill On or Off for the current video. • "On" (the default) auto-detects and fills; "Off" leaves the video alone. • Each toggle shows a brief on-screen message confirming what happened — including when no zoom applies, and why. • The setting resets when you move to another video. PRIVACY • No accounts, no tracking, no data collection. • Everything runs locally in your browser. Nothing is ever sent anywhere. • Works only on youtube.com and requests no other access.