Google aims to win developers over to image format WebP

(Phys.org)—In 2011, news circulated over Google's enhancements to WebP, the image format set to outdistance JPEG and, with more features in a newer version, to take on Portable Network Graphics, another graphics format. The promotional point has been that WebP can create smaller, better-looking images that can help make the web faster. Now, a Thursday posting on The Chromium Blog shows how Google is actively promoting WebP, hoping that developers and other allies will see its edge. Google announced that it started using WebP in its Chrome Web Store, with impressive results. "The Chrome Web Store uses many large promotional images and tiles on its home page, making it a very heavyweight page," wrote Stephen Konig, Product Manager, in the blog, "Using WebP to Improve Speed."

"The team was eager to find ways to improve its speed, without sacrificing the user experience or giving up image quality. WebP to the rescue!" he wrote. "By converting PNGs and JPEGs to WebP, the Chrome Web Store was able to reduce image sizes by about 30 percent on average."

Google's point is that the use of WebP on such a site represents important savings and valuable gains. "When you consider that over 60 percent of typical page sizes are images, the benefits can be substantial. WebP translates directly into less bandwidth consumption, decreased latency, faster page loads, better battery consumption on mobile, and overall happier users," wrote Konig.

WebP is an image compression format for Web images, based on WebM's VP8 codec. Google's reason to focus on WebP has been to reduce Web page file sizes, which in turn implies faster page-loading times, important for a Web business. "For users, the rubber meets the road when it comes to how fast the page loads though. On this score, with WebP we were able to reduce average home page load time by nearly one-third—a huge benefit for our users," said Konig.

The WebP site defines itself as a "method of lossy compression that can be used on photographic images. The degree of compression is adjustable so a user can choose the trade-off between file size and image quality. WebP typically achieves an average of 39 percent more compression than JPEG and JPEG 2000, without loss of image quality."

PNG, meanwhile, outside Google's WebP promotional quarters, is regarded as a popular image format among its fans, said to work well with line art, text, and logos. Google honed in on PNG last year in an August 2012 paper titled "Lossless and Transparency Encoding in WebP," by Jyrki Alakuijala.

The compression and decompression characteristics of WebP were compared with libpng and pngout. "We compare the resource usage of WebP encoder/decoder to that of PNG in both lossless and lossy modes. We use a corpus of 1000 randomly chosen translucent PNG images from the web, and simpler measurements to show variation in performance. We have recompressed the PNGs in our corpus to compare WebP images to size-optimized PNGs." He said the results showed that WebP was "a good replacement" for PNG for use on the web regarding size and processing speed.

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