Google publishes Zopfli as open-source compression algorithm to speed up Web downloads

Compression is about 100 times slower than conventional methods but compresses about 5 percent better, Google said

Google is open-sourcing a new general purpose data compression library called Zopfli that can be used to speed up Web downloads.

The Zopfli Compression Algorithm, which got its name from a Swiss bread recipe, is an implementation of the Deflate compression algorithm that creates a smaller output size compared to previous techniques, wrote Lode Vandevenne, a software engineer with Google's Compression Team, on the Google Open Source Blog on Thursday.

"The smaller compressed size allows for better space utilization, faster data transmission, and lower Web page load latencies. Furthermore, the smaller compressed size has additional benefits in mobile use, such as lower data transfer fees and reduced battery use," Vandevenne wrote.

The more exhaustive compression techniques used achieve higher data density but also make the compression a lot slower. This does not affect the decompression speed though, Vandenne wrote.

Zopfli is a compression-only library and existing software can be used to decompress the data, he said. Zopfli is compatible with Zip, PNG, gzip and HTTP requests among others, Vandevenne added.

Zopfli's output is generally 3 percent to 8 percent smaller compared to zlib, another compression library based on the Deflate compression algorithm, according to Vandevenne. "We believe that Zopfli represents the state of the art in Deflate-compatible compression," he said.

"This compressor takes more time (~100x slower), but compresses around 5 percent better than zlib and better than any other zlib-compatible compressor we have found," Google said on Zopfli's Google Code page. The code is available under Apache License 2.0.

The new compression library however requires 2 to 3 times more CPU time than zlib at maximum quality. Therefore, it is best suited for applications where data is compressed once and sent over the network many times, such as static content for the Web, Vandevenne said.

Vandevenne and his colleague Jyrki Alakuijala, a Google software engineer who also worked on the project, recommend in their research paper to use Zopfli "for compression of static content and other content where data transfer or storage costs are more significant than the increase in CPU time."

"By open sourcing Zopfli, thus allowing webmasters to better optimize the size of frequently accessed static content, we hope to make the Internet a bit faster for all of us," Vandevenne said.

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.

Tags open sourceGooglesoftwareLode VandevenneJyrki Alakuijala

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Loek Essers

IDG News Service
Show Comments

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Tom Pope

Dynabook Portégé X30L-G

Ultimately this laptop has achieved everything I would hope for in a laptop for work, while fitting that into a form factor and weight that is remarkable.

Tom Sellers

MSI P65

This smart laptop was enjoyable to use and great to work on – creating content was super simple.

Lolita Wang

MSI GT76

It really doesn’t get more “gaming laptop” than this.

Jack Jeffries

MSI GS75

As the Maserati or BMW of laptops, it would fit perfectly in the hands of a professional needing firepower under the hood, sophistication and class on the surface, and gaming prowess (sports mode if you will) in between.

Taylor Carr

MSI PS63

The MSI PS63 is an amazing laptop and I would definitely consider buying one in the future.

Christopher Low

Brother RJ-4230B

This small mobile printer is exactly what I need for invoicing and other jobs such as sending fellow tradesman details or step-by-step instructions that I can easily print off from my phone or the Web.

Featured Content

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?