Wirebook › Glossary › Compression
What is compression?
In one sentence: Squeezing data so it takes fewer bits: a video call describes patterns and changes instead of every pixel, so it fits a thinner pipe.
A little more
Compression finds patterns so the same information needs fewer bits. A video encoder notices that a wall hardly changes between pictures and that a face moves a little, then sends a short description instead of every pixel. The other device rebuilds an approximate picture from that description.
Lossless compression (like a zip file) rebuilds the exact original. Video calls use lossy compression: they throw away detail you are less likely to notice so the stream fits a thin pipe. When the pipe shrinks further, the encoder throws away more detail.
See it in action
- BonusWhy does a video call go blurry when the connection is slow?Dial a pretend video call's bandwidth thinner, spend a tiny 10-bit budget on eyes vs mouth vs wallpaper to still read a facial expression, then reveal the clear face.7 min · interactive
- BonusWhy does zipping photos barely make them smaller?Guess which four suitcase items will squash — a repeating chorus, a letter, a camera photo and TV snow — then pack them with a real (tiny) compressor and see.7 min · interactive
- BonusWhat happens when you squish a video too much?Squish a real (tiny) picture the way phones squish video: watch thin whiskers crumble first, then 8x8 blocks appear, then a splat.10 min · interactive
Do it for real
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