You might think that data com­pres­sion is a solved problem, lossless or lossy. But, no. Gzip and related formats like zlib, Zip, and PNG that use the DEFLATE algorithm were great 25 years ago, still do a decent job, and are completely ubiquitous and in­dis­pens­able, but there are better, smarter algorithms now.

Google has announced two new com­pres­sion formats in the last couple of years, Zopfli and Brotli. Zopfli does a better job of generating Deflate-compatible data, although it’s very slow. Brotli gives ~20% better com­pres­sion than Deflate, but at about the same speed. Then there’s xz, which grew out of 7-zip, and also works well.

Zstandard has just been announced by Facebook and it sounds like it does a great all-round job of achieving high com­pres­sion ratios at high speed. The an­nounce­ment article is worth reading.

There are also several new lossless image com­pres­sion algorithms: FLIF, BPG, and WebP, all of which outperform the venerable PNG.