From the Mozilla Research blog comes the news on Tuesday that the "Open Web" powerhouse behind the Firefox browser is releasing mozjpeg 2.0. The announcement comes from Josh Aas, senior technology strategist at Mozilla Corporation. The release is a result of Mozilla's project that set out to provide a production-quality JPEG encoder to improve compression and at the same time be compatible with most decoders. Mozilla had said in March that this was a new project for working on a production-quality JPEG encoder. JPEG is the popular image format that has shown staying power since 1992. The benefits from this attention to an encoder are seen as reduced page-load times and a better user experience for sites that host images.
Aas said that "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."
What's that you're saying, a JPEG encoder that can create smaller JPEGs without compromising the visual quality of photos? Clearly, Facebook is interested and also said on Tuesday that, in a bid to improve the compression of images on facebook.com, they are testing mozjpeg 2.0. What's more, the world's largest social network donated $60,000 toward developing the technology, including the mozjpeg 3.0 to come, according to the Mozilla Research announcement.
Aas said that, "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."
Commenting in TechRadar, JR Bookwalter said, "Facebook has good reason to embrace such technology: After all, the social network processes millions of photos each and every day, and even a seemingly modest five percent could reap big rewards when it comes to bandwidth."
As for technical details, Aas had said back in March that the next goal in the project would be to improve encoding through the use of trellis quantization, Trellis quantization is an algorithm that can improve data compression. Aas said Tuesday that the major feature in this release is in fact trellis quantization, which he said improves compression for baseline and progressive JPEGs without sacrificing compatibility. "Previous versions of mozjpeg only improved compression for progressive JPEGs," he said.
The cjpeg utility supports JPEG input to simplify re-compression workflows. Also, options were added to tune for PSNR, PSNR-HVS-M, SSIM, and MS-SSIM metrics. He said another improvement is that "We now generate a single DC scan by default in order to be compatible with decoders that can't handle arbitrary DC scans."