Two years ago, Google released the Zopfli compression algorithm, which saw large-scale interest. Yesterday, the company followed it up that with a new open-source compression algorithm known as Brotli.
Zopfli was quickly adopted by developers building PNG optimizers or other Web-useful items, like font compression. The goal for Brotli is to enable even more use cases for developers in need of saving space or lowering bandwidth usage.
Zoltan Szabadka, software engineer on the compression team at Google, wrote a blog entry describing the benefits of Brotli. “While Zopfli is Deflate-compatible, Brotli is a whole new data format. This new format allows us to get 20% to 26% higher compression ratios over Zopfli. In our study ‘Comparison of Brotli, Deflate, Zopfli, LZMA, LZHAM and Bzip2 Compression Algorithms,’ we show that Brotli is roughly as fast as zlib’s Deflate implementation. At the same time, it compresses slightly more densely than LZMA and bzip2 on the Canterbury corpus. The higher data density is achieved by a second-order context modeling, reuse of entropy codes, larger memory window of past data, and joint distribution codes. Just like Zopfli, the new algorithm is named after Swiss bakery products. Brötli means ‘small bread’ in Swiss German.”
Brotli is still very new, and has yet to be supported across browsers.