The future of the JPEG standard

The term JPEG is synonymous with digital image file types and billions of JPEGs are now created every year. However, the format is only 18 years old, introduced for the first time in 1992.

The name is an acronym for the Joint Photographic Experts Group, a working group of the International Organization for Standardization and the International Electrotechnical Commission. Its appeal has been its lossy compression method that allows photographs to be saved as very small files for web usage and easy sharing.

Over the years, the organization has created a number of variations on the JPEG format to cater to the ever-changing needs of the market. This has included multi-picture formats, 3D, lossless compression and video formats.

JPEG 2000

JPEG 2000 is a flexible format that offers a number of advantages over the standard JPEG, including an improved compression process, a choice of lossless or lossy compression and high dynamic range support. It can also be used for digital video.

High-throughput JPEG 2000 (HTJ2K) was added to the JPEG 2000 standard in 2019, providing 10 times greater throughput for moderate to highly compressed files and up to 30 times more for lossless coding. It also offered truly reversible transcoding to and from J2K-1, thanks to a new HT block coder.

The high-throughput lossless coding makes it suitable for professional video, while the high-energy efficiency means it is ideal for mobile and satellite imaging usage. In newly updated Parts 16 and 17, support has also been added to allow the encapsulation of JPEG 2000 in the HEIF format and additional tools for the coding of discontinuous media.

JPEG XS

JPEG XS was introduced in 2018 and is designed for low-latency, multiple encoding-decoding cycles. It replaces previously uncompressed data with a visually lossless compression and supports professional formats, including RGB/444, RGBA/4444, YCbCr 444/422, YCbCrA 4444/42224 and YCbCr 420. It is ideally suited for professional video and IP transport, as well as virtual and augmented reality usage.

In June 2020, the capability was added to transport JPEG XS in a range of file formats, including RTP, MPEG2-TS, video over IP, JXS, MP4, HEIF and MXF. A further extension is under development for Bayer-based RAW camera data.

JPEG Systems

JPEG Systems defines the overall framework for future and legacy JPEG standards, to ensure better interoperability between these standards. First launched in 2016, recent additions have included extensions to standards for privacy, security and IPR, a universal metadata box format (JUMBF) and a standard for 360-degree images.

Despite these new features, the files remain backwardly compatible for image viewing using old JPEG decoders, while new decoders will allow access to all of the extended features.

JPEG Pleno

JPEG Pleno provides a framework for what it describes as “imaging modalities.” These are light representations that provide 3D spatial representations for the likes of texture-plus-depth, light field, point cloud and holographic imaging.

For this reason, the standard is considered more than just a method of encoding. It is a presentation framework that provides support for image manipulation, metadata, access and interaction.

Launched this year, Part 1 defines the framework and relationships between the components of the standard. Specifics for light field coding are due in the second half of 2020, while conformance testing and reference software parts are due in 2021.

JPEG XL

JPEG XL is designed to replace the existing JPEG format, providing higher quality images with greater compression. This ensures the highest possible image quality for professional photographers while requiring less storage space.

The advantage of JPEG XL is that the format is backwardly compatible, meaning that traditional JPEG decoders will still be able to open the image, and newer JPEG XL decoders will be able to call on the embedded metadata to view a higher quality version. Existing JPEG files can also be losslessly encoded to JPEG XL to significantly reduce the file size. This file can still be restored to an original JPEG file at any time for viewing on older applications.

This royalty-free platform is due for publication in 2021 with free and open-source software available under the Apache 2 license.

Future developments

Aside from the current lineup, JPEG is also exploring different avenues for its standards that may lead to new formats in the future.

Workshops and discussion sessions have taken place with stakeholders to consider the use case for a standardization related to blockchain and distributed ledger technologies. There are a number of privacy and security-related challenges that could benefit from this technology, including digital rights management, integrity verification and authenticity.

The JPEG committee has also started to explore artificial intelligence coding technologies. Many coding technologies already rely on AI to improve their efficiency. A learning-based coding technology could unveil new and more intelligent ways to present images, possibly leading to more efficient practices.

Imaging today is more important than ever, and the JPEG committee is committed not only to continuing to develop its current solutions, but also to strive for new ones. Your JPEG file could look very different in another 18 years.