Two weeks ago Dropbox made a fascinating announcement of a new “streaming image format”:

Lepton achieves a 22% savings reduction for existing JPEG images, by predicting coefficients in JPEG blocks and feeding those predictions as context into an arithmetic coder. Lepton preserves the original file bit-for-bit perfectly. It compresses JPEG files at a rate of 5 megabytes per second and decodes them back to the original bits at 15 megabytes per second, securely, deterministically, and in under 24 megabytes of memory.

We have used Lepton to encode 16 billion images saved to Dropbox, and are rapidly recoding our older images. Lepton has already saved Dropbox multiple petabytes of space.

I’m not a fan of the JPEG image format, but since it’s so pervasive and everyone is taking and storing so many photos at this point, this is important and very impressive. Read the full post on the Dropbox Technical Blog for all the technical details. Lepton is open source under the Apache license and available on GitHub, so we all benefit.

[Via TechCrunch]