Articles by Day: October 5, 2010
To improve on the compression that JPEG provides, we used an image compressor based on the VP8 codec that Google open-sourced in May 2010. We applied the techniques from VP8 video intra frame coding to push the envelope in still image coding. We also adapted a very lightweight container based on RIFF. While this container format contributes a minimal overhead of only 20 bytes per image, it is extensible to allow authors to save meta-data they would like to store.
While the benefits of a VP8 based image format were clear in theory, we needed to test them in the real world. In order to gauge the effectiveness of our efforts, we randomly picked about 1,000,000 images from the web (mostly JPEGs and some PNGs and GIFs) and re-encoded them to WebP without perceptibly compromising visual quality. This resulted in an average 39% reduction in file size. We expect that developers will achieve in practice even better file size reduction with WebP when starting from an uncompressed image.
There is a conversion tool, and Google says that an alpha transparency layer is coming soon to the format, which will give it PNG-style transparency. Oddly, the conversion tool is only currently available for Linux users!
Google’s WebP info pages contain a Gallery showing comparisons between JPG and WebP images. Since browsers can’t yet support WebP images, they are inside some sort of “PNG container” as they mention on the site.
The surface claim here is that Google wants to modernize compressed image formats for use on the web, to make downloading webpages and images faster. Obviously, as an advertising company the faster a page loads, the quicker you see their ads.
Seeing as how the format is Open Source, I can’t really see any downside to Google being the originator of the format. The GIF format ran into issues since it was patented, which led to the development of the PNG format. The patent on the GIF format has since expired, according to Wikipedia.
The real question is this: will it be adopted, and how widespread will the adoption be? The first step is for browsers to support the format, then those who create images. Will the major graphics software developers support WebP, such as Adobe? I think that will be a deciding factor. Using a command-line prompt to convert images is not going to help the adoption rate.
Some independent graphics software developers have already jumped on the WebP bandwagon. Pixelmator has already started adding WebP support to their software. But I think it’ll take seeing WebP support in software that is more widespread across the graphics and web industry before we will see any widespread support. Yes, I am talking about Photoshop and Illustrator.
So as creative types, I’m curious what our readers think of the new format, and how likely you think you’ll be to use the new format if/when Adobe and the like start supporting it. Will the file size savings be worth moving over to a new format, one that may present compatibility issues at the outset when sharing files with others without support for the format in their software?
Is the file size saving something that concerns you as a graphic designer or a web developer? How big of a role does it play in your creative process?