Letterbox Detection
Crop the black bars baked into the video file itself – automatically on most sites, or by measuring them by hand on protected streams. A Pro feature.
Some black bars aren't added by the site — they're encoded into the video file itself, the way a 2.39:1 movie is delivered inside a 16:9 frame. No mode can resize those away because they're part of the picture. Letterbox Detection (Pro) finds the real image inside the frame and crops the baked-in bars out.
Detect
On most sites, tap Detect and UltraWideo measures the bars and crops them automatically — the picture reframes to just the real content.
Measure (for protected streams)
On DRM-protected streams like Netflix or Prime Video, browsers block reading pixels from the video, so automatic Detect can't see the frame. Use Measure instead: drag over the top black bar and release, and UltraWideo applies the matching crop.
When to use it
Reach for Letterbox Detection on films that still show permanent black bars even after Upscale — typically anything shot in a wider-than-16:9 cinematic ratio.
Good to know
Prefer to do it by hand for free? The Scale controls can crop baked-in bars manually on any video — Letterbox Detection just makes it one tap (or one drag) instead of fiddling with values.
Unlock this with Pro
This is a Pro feature. Upgrade once and every Pro tool is yours, on every browser.