applications with excellent compression capability and important additional functionalities. The primary intended application of JPEG XR is the representation of continuous-tone still images such as photographic images.
As of 2008, the most widely used digital photography format is a nominal implementation of the first JPEG coding format as specified in Rec. ITU-T T.81 | ISO/IEC 10918-1. This encoding uses a bit depth of 8 for each of three channels, resulting in 256 representable values per channel (a total of 16 777 216 representable color values). More demanding applications may require a bit depth of 16, providing 65,536 representable values for each channel, and resulting in over 2.8 * 10^14 color values. Additional scenarios may necessitate even greater bit depths and sample representation formats. When memory or processing power is at a premium, as few as five or six bits per channel may be used.
The JPEG XR specification enables greater effective use of compressed imagery with this broadened diversity of application requirements. JPEG XR supports a wide range of color encoding formats including monochrome, RGB, CMYK and n-component encodings using a variety of unsigned integer, fixed point, and floating point decoded numerical representations with a variety of bit depths. The primary goal is to provide a compressed format specification appropriate for a wide range of applications while keeping the implementation requirements for encoders and decoders simple. A special focus of the design is support for emerging high dynamic range (HDR) imagery applications.
JPEG XR combines the benefits of optimized image quality and compression efficiency together with low-complexity encoding and decoding implementation requirements. It also provides an extensive set of additional functionalities, including: