Lepton – image compression tool and file format

Lepton is a tool and file format for losslessly compressing JPEGs by an average of 22%. It provides lossless, bit-exact storage for any type of photo, whether it be for archival purposes, or for serving live.

It achieves this saving 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.

This tool can be used to archive large photo collections, or to serve images live and save 22% bandwidth.

Lepton can decompress significantly faster than line-speed for typical consumer and business connections. Lepton is a fully streamable format, meaning the decompression can be applied to any file as that file is being transferred over the network. Hence, streaming overlaps the computational work of the decompression with the file transfer itself, hiding latency from the user.

Lepton is free and open source software.

Website: github.com/dropbox/lepton
Support: Photo Compression
Developer: Dropbox, Inc. )Daniel Reiter Horn, Ken Elkabany, Keith Winstein, Chris Lesniewski, Mario Brito, Matthias Stirner, Mikhail T
License: Apache License 2.0

Lepton is written in C++. Learn C++ with our recommended free books and free tutorials.

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