Resize a video to 854x480, the 480p standard-definition frame.
The odd number
16:9 at 480 pixels tall works out to 853.33 pixels wide. H.264 encodes even dimensions only, so the width rounds up to 854.
That puts the frame at 1.779:1 against 16:9’s 1.778:1. The difference is about a tenth of a percent, so a widescreen source loses well under a pixel and the result is indistinguishable from an exact fit.
You will also see 848x480 and 852x480 in the wild, from encoders that round differently. All three are the same frame for practical purposes.
What it costs and saves
| Size | Pixels per frame | Against 1080p |
|---|---|---|
| 1920x1080 | 2,073,600 | 100% |
| 1280x720 | 921,600 | 44% |
| 854x480 | 409,920 | 20% |
At a fifth of the data of 1080p, this is the size to reach for when a limit is genuinely tight and the footage can take it.
Where it holds up
Handheld footage watched small, background loops, previews, and anything going over a slow connection.
Where it does not: text, user interfaces, screen recordings, and anything watched full screen on a laptop or larger. At 480p the loss is not subtle.