Mozilla improves JPEG encoding

We’re pleased to announce the release of mozjpeg 2.0. Early this year, we explained that we started this project to provide a production-quality JPEG encoder that improves compression while maintaining compatibility with the vast majority of deployed decoders. The end goal is to reduce page load times and ultimately create an enhanced user experience for sites hosting images.

With today’s release, mozjpeg 2.0 can reduce file sizes for both baseline and progressive JPEGs by 5% on average compared to those produced by libjpeg-turbo, the standard JPEG library upon which mozjpeg is based. Many images will see further reductions.

Facebook announced today that they are testing mozjpeg 2.0 to improve the compression of images on facebook.com. It has also donated $60,000 to contribute to the ongoing development of the technology, including the next iteration, mozjpeg 3.0.

The major feature in this release is trellis quantization, which improves compression for both baseline and progressive JPEGs without sacrificing anything in terms of compatibility. Previous versions of mozjpeg only improved compression for progressive JPEGs.

Mozilla Research Blog: https://blog.mozilla.org/research/2014/07/15/mozilla-advances-jpeg-encoding-with-mozjpeg-2-0/