Letterboxing
Letterboxing is the technique of adding black bars above and below a video so a wide image fits a narrower screen without cropping or stretching. It happens, for example, when a 2.40:1 cinema film plays on a 16:9 TV. Adding bars on the left and right instead, for narrow video on a wide screen, is called pillarboxing.
Why it matters
Letterboxing protects the full picture, but it also wastes screen space. On phones, black bars can shrink a video to a thin strip, which hurts engagement. Platforms must decide when to keep the original framing and when to crop, and that choice affects how the content feels.
How it works
- The player compares the video's shape with the screen's shape.
- If the video is wider than the screen, it is scaled to fit the width.
- Black bars fill the empty space above and below the picture.
- Narrow video on a wide screen gets bars at the sides instead, called pillarboxing.
Why do movies have black bars?
Movies have black bars because many are filmed wider than a TV or phone screen. A film shot at about 2.4:1 is wider than a 16:9 screen, so bars fill the space above and below to show the full picture without cropping. Removing them would mean cutting off the sides.
Letterboxing vs pillarboxing: what is the difference?
Letterboxing adds bars above and below a wide video, while pillarboxing adds bars on the left and right of a narrow one. Letterboxing happens when a cinema film plays on a 16:9 TV. Pillarboxing happens when old 4:3 footage or vertical video plays on a widescreen display.
Where it's used
OTT services keep black bars on films so viewers see the director's full frame, while short video apps and creator platforms usually crop wide clips to fill a phone screen instead.
By the numbers
- Widescreen 1.78:1 (16:9) fills a widescreen TV, while common film ratios such as 1.85:1 and 2.40:1 show letterbox bars on it. (Letterboxing (filming) (Wikipedia))
