Ultrafill.Get Ultrafill

ULTRAFILL / ZOOM VIDEO TO FILL.

Make room
for the picture.

Zoom, crop and pan HTML5 video to fill your player.
For Firefox, Zen and Chromium, with optional local picture controls.

Choose your browser See what changes

No signup for playback. No premium tier. No analytics.

Firefox + ChromiumOpen source · MITLocal picture processingFree, without an asterisk

SAME PROJECT. YOUR BROWSER.

Choose your
browser.

One open-source project.
Clear options for installing it.

FIREFOX ADD-ONS

Firefox / Zen

Install Ultrafill from Mozilla Add-ons. Fill, crop and pan video, then make yourself comfortable with optional local picture controls.

Install for Firefox

CHROME WEB STORE

Chrome / Chromium

Install Ultrafill from the Chrome Web Store. Zoom, crop and pan video in Chrome and compatible Chromium browsers, with the same optional local picture controls.

Install for Chrome

LESS LETTERBOX. MORE LANDSCAPE.

A frame worth
playing with.

Pick a player shape. Toggle fill. Move the focus.
That’s the idea—try it right here.

Illustrated landscape demonstrating how filling a player crops the pictureOriginal picture
16:9 player · original picture

Interactive framing illustration. Filling crops the edges; it doesn’t invent missing picture. Actual results depend on the video and player.

SMALL CONTROLS. USEFUL DIFFERENCES.

Settle in.
Then fine-tune.

Start with the frame. Everything else is optional—and included.

Alt+ZFill on. Fill off.
01

Find your frame.

Zoom, pan, custom ratios and stable black-bar detection. A quiet, draggable panel keeps the controls inside the player.

02

Keep it comfortable.

Brightness, contrast, shadows, sharpness and selective vibrance. Elastic stretch protects the center while the edges take more of the change.

03

Make the light yours.

Readable video can drive sampled ambience and an explicit audio pulse. Motion interpolation and HDR highlights run only where their requirements are met.

04

Come back to your setup.

Named profiles and Video, Tab, Site or Global memory. Export your settings. Opt into browser-account sync only if you want it.

REAL BROWSERS. REAL CONTROLS.

At home
in your player.

Firefox and Chromium controls on an original local sample video.
No streaming account or uploaded media needed.

Ultrafill Firefox panel showing zoom, picture aspect ratio and horizontal and vertical pan controls
Firefox: Fill your player and fine-tune zoom, aspect ratio and pan with the in-player controls.
Ultrafill Chromium panel showing local brightness, contrast, saturation and shadow adjustments
Chromium: Adjust brightness, contrast, saturation and shadows locally while keeping playback in your browser.

A PUBLIC PROJECT. A SIMPLE PROMISE.

Yours to use.
Ours to improve.

Ultrafill is maintained by Redbull Lunatic and released under the MIT license. Help fix a player, improve accessibility, review a translation, or send a small patch.

Explore the source Contact the maintainer ↗

Pseudonymous contributions welcome. Small patches and thoughtful feedback count.

The picture is
the point.

  • No analytics or advertising
  • No payment system or premium gates
  • No video or audio uploads
  • No forced account for core features
  • Explicit opt-in browser sync
Read the privacy policy

A FEW THINGS TO KNOW.

Clear edges.

Does it work on every video?

Framing works with many HTML5 players, including embeds and discoverable open shadow roots. Sites can still impose restrictions. Pixel effects need readable frames; protected or unreadable media keeps ordinary playback and manual framing. Native Picture-in-Picture and closed site shadow roots have browser limits.

Is everything hardware accelerated?

Picture effects use WebGL2, and supported HDR uses WebGPU. The browser chooses a physical or software graphics backend. Optical-flow search for interpolation currently runs on the CPU, with frame synthesis in the graphics pipeline. The local performance display reports the backend honestly and reduces work under load.

What does HDR support actually mean?

HDR highlights need known SDR source metadata, a compatible HDR display/output and an extended WebGPU canvas. Native HDR sources retain their native pipeline. Unsupported configurations say so. This does not recover detail missing from the original recording.

Does it collect my watching habits?

Ultrafill has no analytics or developer data server. Frames and audio energy stay local. Browser sync is off by default; enabling it sends preferences, profiles and chosen site rules through your browser account, excluding saved site/tab viewing state. See the privacy policy for details.

What about Chromium browsers?

Chrome and Chromium use the same Manifest V3 extension build, sharing the core source with Firefox. Install for Chrome through the Chrome Web Store, or explore the public source.

Can I help without sharing my real name?

Yes. Pseudonymous contributions are welcome. Use a name and email you are comfortable publishing in Git commits. Small patches can also be sent to the project email. Please never send private media or account credentials.

THE NEXT VIDEO CAN FEEL A LITTLE BETTER.

Give it the room.

Choose your browser

Free. Open source. Made to stay out of your way.