True high-dynamic-range (HDR) images in a JPEG-compatible still-picture format


• Go beyond tone-mapping
  Approximating high-dynamic range through tone mapping is a solution of the past. True HDR is the future.
• One file, two images
  The same file will be readable by legacy low-dynamic-range (LDR) decoders and HDR decoders, rendering JPEG-XT fully backward compatible.
• True HDR quality + backward compatibility, almost the same size
  20-30% larger than JPEG-LDR: other HDR formats or RAW format cannot compete with JPEG-XT due to their file size.
• Unlocking true HDR for consumers
  JPEG-XT will enable consumers to utilise on details, image data and post-processing capabilities previously inaccessible under JPEG.

THE PROBLEM: JPEG Limitations

Conventional JPEG has limitations: being constrained to images of 8-bit colour depth, it supports only low-dynamic-range (LDR). Consumers expect continuous improvements in image quality and high-dynamic-range (HDR) images deliver on their expectation.

HDR solutions based on tone-mapping are present, but don’t unlock the full potential of HDR images: the information captured is discarded once the picture is processed and formatted in conventional JPEG. Proprietary solutions also prevent interoperability, limiting the range of uses of HDR images. No other standard solutions exist that are also backward compatible.

THE SOLUTION: JPEG-XT

JPEG-XT (ISO/IEC 18477), specifies a series of backward compatible extensions to the legacy JPEG standard (ITU Recommendation T.81 | ISO/IEC 10918-1).

While JPEG is a widely-adopted technology for storing digital images, it doesn't address several requirements that have become important in recent years, such as compression of images with higher bit depth (up to 16 bits), HDR imaging, lossless compression, Wide Colour Gamut (WCG), and representation of alpha channels.

The main benefits of JPEG-XT technology are:

• Backward compatibility
• Interoperability (ISO Standard)
• Preservation of the whole picture information (colours, luminance) and non-destructive edits - data is preserved in the capture and encoding, unlike tone-mapped solutions today
• Portable (JPEG-like memory needs, much smaller than RAW)
• Improved consistent display across all screens, both standard and HDR