WebP
(Software)
What is WebP?
WebP is an image format employing both lossy and lossless compression. It is currently developed by Google, based on technology 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 license. The format was first announced on 30 September in 2010 as a new open standard for lossy compressed true-color graphics on the web, producing smaller files of comparable image quality to the older JPEG scheme. On 3 October 2011, Google added an "Extended File Format" allowing WebP support for animation, ICC profile, XMP and Exif metadata, and tiling (compositing very large images from maximum 16384×16384 tiles). The support for animation allowed for converting older animated GIF to animated WebP. On 18 November 2011, Google began to experiment with lossless compression and support for transparency (alpha channel) in both lossless and lossy modes; support has been enabled by default in libwebp 0.2.0 (16 August 2012). According to Google's measurements, a conversion from PNG to WebP results in a 45% reduction in file size when starting with PNGs found on the web, and a 28% reduction compared to PNGs that are recompressed with pngcrush and PNGOUT. The WebP container (i.e., RIFF container for WebP) allows feature support over and above the basic use case of WebP (i.e., a file containing a single image encoded as a VP8 key frame). The WebP container provides additional support for: * Lossless compression – An image can be losslessly compressed, using the WebP Lossless Format. * Metadata – An image may have metadata stored in Exif or XMP formats. * Transparency – An image may have transparency, i.e., an alpha channel. * Color Profile – An image may have an embedded ICC profile as described by the International Color Consortium. * Animation – An image may have multiple frames with pauses between them, making it an animation. In a comparison made between GIF, APNG and WebP, it was shown, however, that APNG kept lower file size while keeping at least equal quality.