Back in May, Google announced its project to develop a new Web video format, WebM, and the associated codecs. Now, in a post on the Chromium Blog, the company has announced another new format: WebP, a lossy compressed format for photographs and similar images. Like the commonly used JPEG format (also a lossy compressed format), WebP has adjustable compression, so that users can set their desired trade-off between file size and image quality. According to the project home page:
A WebP file consists of VP8 image data, and a container based on RIFF. Webmasters, web developers and browser developers can use the WebP format to create smaller, better looking images that can help make the web faster.
The VP8 image data format is also used in the WebM video format; RIFF is a very light-weight, but extensible, container file format.
Google’s stated reason for introducing the new format is to provide a method that can encode photographs and similar images in smaller files without sacrificing quality. According to the WebP FAQ, Google’s tests have shown an average of 39% more compression than JPEG or JPEG-2000. Given the increasing prevalence of image data on the Web — Google says that “Images and photos make up about 65% of the bytes transmitted per web page today” — this might lead to some worthwhile savings in bandwidth requirements.
(I got, if you will excuse the pun, a graphic demonstration of how much bandwidth images can soak up back around 1990. At the time, we had a full-time data link between our London and Sydney offices, running at the blazing speed of 64Kb / second. (The Internet was in its infancy, and practical connections usually involved leased circuits from a telecom carrier, at considerable expense.) When the link was originally inaugurated, it produced some real time savings and productivity improvements. In a follow-on stage of the project, things were set up so that fax transmissions between the two offices would, by default, go via the leased line. However, when this was done, all the existing users started screaming; their stuff was taking forever, or not getting through at all. The folks that set the thing up had done some homework; they had calculated the size of fax transmission per letter-sized page, and checked on the volume of faxes sent. But when they looked at the actual fax files being sent over the leased link, they found enormously bigger files sizes than they expected. What they had not considered was that users, in order to make the faxes “look nice”, had created a fax form like the company letterhead, including the logo. To make a long story a bit shorter, it turned out that we were using 94+ % of the transmission capacity to send copies of our logo back and forth between England and Australia.)
The WebP project is still in the development stage, so there is not much to try out just now, unless you want to dig into the code. However, Google does have a gallery page, showing some example images encoded with JPEG and WebP, and the comparative file sizes.
Update Thursday, 7 October, 20:40 EDT
There is a “Invited Guest” blog post at Technology Review that discusses the new format. The author, Paul Boutin, reminds us again of the reason Google is focused on making the Web faster.
Speed has always been a mantra at Google. Faster Web pages lead to more Googling by Web users. This, in turn, leads to more ads served by Google, which leads to potentially more ad revenue for the company.
Google is a great technology company, but it also stays admirably focused on what its core business is.