FLIF, which stands for Free Lossless Image Format, is a new lossless image format that is said to provide better compression ration than PNG, lossless JPEG2000, lossless WebP, and lossless BPG for all king of images including medical images, geographical maps, cliparts and so on.
Beside being lossless, FLIF is also progressive, so a lower quality version of the image can be displayed early while the download is still in progress. The developer has uploaded a video comparing how a PNG image and FLIF image would load in a slow network.
Other FLIF features include:
- Lossless compression
- Greyscale, RGB, RGBA
- Up to 16 bits color depth per channel (high dynamic range)
- Interlaced (default) or non-interlaced
- Animation support
- “Encoding and decoding speeds are not blazingly fast, but they are in the right ballpark”
- Based on MANIAC (Meta-Adaptive Near-zero Integer Arithmetic Coding) algorithm developed by Jon Sneyers and Pieter Wuille. (However details don’t seem to be available)
FLIF is open source with the code available on github. However, the code is currently licensed under GPLv3+, which makes it impractical for implementation in other open source projects, like web browsers, or commercial applications. But the developer explained that it is still work in progress, and once there is a library, it might be license under LGPLv3+, oother more permissive license.