This might come as a surprise to you, but there’s not a single JPEG – Joint Photographic Experts Group – image format already but a number of them. In fact, the most common JPEG formats are JPEG XT, JPEG-LS, JPEG 2000, JPEG XR, JBIG, JPEG Pleno and now JPEG XS. Impressed?
To understand why there are so many variations on JPEG, let’s just take a minute to talk about what the JPEG group is trying to solve: encoding and storing complex photographic images as accurately as possible while also minimizing both the resultant size of the file and the speed at which it can be rendered and displayed upon receipt. The wrinkle is that you can’t make the encoding too complicated because it’ll tax less powerful devices.
It’s also important that the standard minimize data loss; if you’re taking a photo of a gorgeous sunset or moody forest, you don’t want to lose colors and have the thousands of pinks or the blue greys of the mist end up represented by only a half-dozen shades:
So JPEG XS is the latest iteration of JPEG encoding/decoding and reflects the latest hardware capabilities of computers and devices connected to the Internet and computers in general. As the JPEG.ORG site says in its jargon-heavy style:
The JPEG XS (ISO/IEC 21122) standard defines a compression algorithm with very low latency and very low complexity. By offering various degrees of parallelism, JPEG XS can be efficiently implemented on various platforms such as FPGAs, ASICs, CPUs and GPUs and excels with high multi-generation robustness. It is particularly optimized for visual lossless compression as defined in ISO/IEC 29170-2 for both natural and synthetic images. The typical compression ratios are between 1:2 and 1:6 for both 4:4:4 and 4:2:2 images and image sequences with up to 16 bit component precision. Typical parameterizations address a maximum algorithmic latency between 1 – 32 video lines for a combined encoder-decoder suite.
The long and short of it: JPEG XS is utilizing the multi-core parallel processing capabilities of modern CPU design to allow encoding and, more importantly, decoding of the image to be faster. Faster decoding = quicker rendering on screen. Compression ratios of 1:2 to 1:6 are good too; an image that might have started out at 300Kb could then be compressed down between 150Kb and a fantastic 50Kb.
Unless you’re a coder who works in the graphics space, however, the good news is that you don’t have to worry – or even be aware of – changes and improvements to the JPEG format. If you use modern graphics and image editing software, it’ll just add JPEG XS internally when it’s ready for prime time, perhaps without even notifying you.
Then the old chicken-and-egg problem will arise for Web browser developers and computer OS developers of when to include JPEG XS support too, but, again, that’ll all happen behind the scenes without you having to do much more than stay up to date with all your software.
Good to know about all the JPEG formats (and all the competing formats like progressive network graphics (PNG) too) but most likely you won’t have to change anything about your workflow as it appears on the scene.
Pro Tip: Have a Web development question? We have tons of HTML and Web design help and tutorials here on the site. Please do check them out!
The post What is JPEG XS? originally appeared on Ask Dave Taylor.