It supports both lossy and lossless compression, as well as animation and alpha transparency.
WEBP announced by Google on 2010 as a new open format for lossy compressed true-color graphics on the web, producing files that were smaller than JPEG files for comparable image quality.
It was based on technology which Google had acquired with the purchase of On2 Technologies.
As a derivative of the VP8 video format, it is a sister project to the WebM multimedia container format.
WEBP-related software is released under a BSD free software license.
Google added an "Extended File Format" allowing WEBP support for animation, ICC profile, XMP and Exif metadata, and tiling.
Tiling support was never finalized and was removed from the spec again. Older animated GIF files can be converted to animated WEBP.
Later Google announced a new lossless compression mode.
A conversion from PNG to WEBP resulted in a 45% reduction in file size.
In 2016, Apple added WEBP support to macOS Sierra and iOS 10.
In 2020, WEBP support was added in Safari version 14.
The supporting libwebp library reached version 1.0 in 2018.
In 2021, web browsers that support WEBP had 96% market share.
WEBP's lossless compression was designed by Google software engineer Jyrki Alakuijala.
It uses advanced techniques such as dedicated entropy codes for different color channels, exploiting 2D locality of backward reference distances and a color cache of recently used colors.
This complements basic techniques such as dictionary coding, Huffman coding and color indexing transform.
Webp uses a recursive definition: all of the control images, such as the local entropy code selection, are encoded the same way as the whole image itself.
What is WEBP?
WEBP is a raster graphics file format developed by Google intended as a replacement for JPEG, PNG, and GIF file formats.