• JPEG-HDR

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    • JPEG-HDR produces true high-dynamic-range images in a JPEG-compatible still-photo format for smartphones and other cameras.

    • JPEG-HDR Benefits

      • Backward Compatible

        JPEG-HDR® works completely and seamlessly on all existing devices and applications within the vast existing JPEG ecosystem, actually advancing it by adding capabilities.

      • Part of the JPEG Standard (ISO)

        JPEG-HDR images are independent of software and camera. RAW images, by comparison, are specific to each camera model, proprietary, and require special software for viewing.

      • Preserves All Information—No Compromises

        JPEG-HDR images always include all the color and luminance from the highlights to the shadows. Edits are nondestructive, so users can make initial decisions on keeping and sharing, and change them later if desired.

      • Portable

        While RAW files are memory hogs, JPEG-HDR files are much smaller, only moderately larger than standard JPEGs. This encourages and supports easy and economical sharing via the cloud.

      • Consistent Display

        JPEG-HDR photos will display consistently across all screens, both standard and HDR. The images are future ready—they'll take full advantage of the increasing capabilities of upcoming devices and displays.

      • Better Print Quality

        Printers focus on color gamut (rather than the luminance emphasis of devices). Because JPEG-HDR images preserve all the color information, they enable better and richer prints.

    • JPEG-HDR format allows for capturing multiple exposures with today's 12-bit or greater sensors, and it outputs 20-bit or greater true HDR images.

      • The Problem: JPEG Limitations

        JPEG, an ISO standard for more than 20 years, has been the format most commonly used for sharing and storing still images. But conventional JPEG has a fundamental limitation: it's constrained to images of 8-bit color depth, so it supports only low dynamic range (LDR). This presents a challenge, as consumers increasingly demand high-dynamic-range (HDR) images. Those standard LDR JPEG images are proving to be a bottleneck in the still-imaging ecosystem, as TVs, monitors, smartphones, and other portable devices are capable of supporting HDR.

        Smartphones now offer a so-called HDR mode, taking multiple exposures (typically three) and combining them using proprietary tone-mapping to improve color and contrast. However, the final image is still 8-bit JPEG. The true HDR information is discarded.

    • Standard HDR format captures multiple exposures with 12-bit or greater sensors, and it outputs 8-bit low-dynamic-range (LDR) images.

      • Typical Smartphone "HDR"

        • Offers some improvement in highlight and shadow detail
        • Uses proprietary algorithms
        • Processes the final image into conventional JPEG and discards unused information

        The Solution: JPEG-HDR

        JPEG-HDR is a still-image coding technology that allows the storage and distribution of true high-dynamic-range data—beyond 8-bit tone-mapped images—very efficiently in a compact format. It is backward compatible with conventional JPEG and has been standardized as ISO/IEC 18477 (JPEG eXTensions) Part 2.

        True HDR in a Compact and Compatible Format

        JPEG-HDR overcomes the limitations of conventional JPEG, enabling the capture and storage of true HDR images while maintaining small file sizes and backward compatibility. It takes full advantage of the 12-bit and greater multiple exposure capability of today's sensors.

        JPEG-HDR preserves all the information from the original exposures and carries it in metadata. File sizes are only moderately larger, typically 20 to 30 percent, than conventional JPEG files.

        The JPEG-HDR format supports a wider color gamut and range of luminance and is ideal for HDR displays, enhanced photo editing, and printouts, without requiring storage and transmission of large image files. It avoids clipping and loss of detail.

        Advantages of JPEG-HDR over RAW Files

        JPEG-HDR dynamic range matches or exceeds the dynamic range achieved through processing RAW files from high-end digital cameras, without the huge RAW file sizes and the high effort and steep learning curves of postprocessing software. It has additional practical advantages over RAW:

        • JPEG-HDR is an open standard that does not require proprietary algorithms for accurate decoding. By contrast, RAW is not a standard, and images vary by brand and camera model. 
        • JPEG-HDR offers seamless sharing and takes full advantage of the intelligence of sharing apps and services while keeping file sizes small. 
        • JPEG-HDR has only a small impact on development time and costs.

      • JPEG-HDR Brings True HDR Benefits to the JPEG Standard

        The JPEG-HDR format stores all the data in high dynamic range beyond 8 bits, so that users can use this entire range to edit images during postprocessing. By comparison, the HDR modes on current smartphones automatically tone-map images based on proprietary algorithms and provide a single compressed image without the original HDR data, preventing postprocessing to the user's preference.

        Tone Mapping: Not True HDR

        Tone mapping is a technique used in image processing to map one set of colors to another to approximate the appearance of high-dynamic-range images in a medium that has a more limited dynamic range. Tone mapping addresses the problem of strong contrast reduction from the original scene radiance to the displayable range, while preserving the image details and color appearance that are important for appreciating the original scene content.

        JPEG-HDR: Backward Compatible with Conventional JPEG

        JPEG-HDR is a backward-compatible extension of JPEG, standardized by ISO toward high-dynamic-range photography. A legacy JPEG decoder will decode the baseline JPEG streams embedded in JPEG-HDR, typically tone-mapped 8-bit images. A JPEG-HDR decoder will be able to restore the complete HDR images using the additional data in the extended part of the new format. JPEG-HDR files are typically 20 percent to 30 percent larger than conventional JPEG files.

        Other HDR Formats: Limitations

        HDR image formats exist, such as Radiance (.hdr) and Open EXR (.exr), but their files are typically 10 times larger than JPEG-HDR files, and are thus not suitable for many use cases, such as sharing and cloud syncing. Another format, JPEG-XR, can support HDR, but it failed to become popular in the consumer space because it lacks backward compatibility with JPEG.

        Incorporating JPEG-HDR in Your Products

        If you are a capture-device manufacturer, you can either build your own implementation or use an implementation developed by a third party. Please contact Dolby for more information. If you are a PC software provider or a mobile app developer and are interested in supporting the JPEG-HDR format, you can build your own implementations based on the reference software implementation that we will publish soon. Please check this site in future to download this implementation.

        JPEG-HDR Benefits for Developing Mobile Photo Apps

        JPEG-HDR will deliver additional image data not previously available to you, greatly expanding your capabilities. For example, you can do better photo enhancements, and even better tone mapping. You can see image details that were not previously visible, which will help increase understanding of the images and help you create better storytelling for your end users. You can also support your users with better print quality.

         

      • JPEG Standard

        JPEG-HDR (ISO/IEC 18477) is part of the still image coding standards

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