image can be segmented into tile regions. The data for each region can be decoded separately. This enables rapid access to parts of an image without needing to decode the entire image. When a type of tiling referred to as "soft tiling" is used, the tile region structuring can be changed without fully decoding the image and without introducing additional distortion. Support for more color accuracy JPEG XR supports a wide variety of image color representations in addition to the conventional 8-bit-per-sample YUV (formally YCbCr) 4:2:0 encoding that is typically used for the original JPEG standard. For support of images using an RGB color space, JPEG XR includes an internal conversion to the YCoCg color space, and supports a variety of bit depth and color representation packing schemes. These can be used with and without an accompanying alpha channel for shape masking and semi-transparency support, and some of them have much higher precision than what has typically been used for image coding. They include: Low bit-depth packings of RGB into 16 bits per pixel using 5 bits for each channel or 5 bits for red and blue and 6 bits for green 8 bits per component (sometimes called true color) packed into 24 or 32 bits per pixel 10 bits per component in a 32 bit packed representation (one of several higher-precision varieties of color representation known as deep color) 16 bits per component as integers, fixed-point numbers, or half-precision floating-point numbers packed into 48 or 64 bits 32 bits per component as fixed-point numbers or full-precision floating point numbers packed into 96 or 128 bits (for which lossless coding is not supported due to the excessively high precision) JPEG XR also supports 16 bits per component (64-bit per pixel) integer CMYK color model. 16-bit and 32-bit fixed point color component codings are also supported in JPEG XR. In such encodings, the most-significant 4 bits of each color channel are treated as providing additional "headroom" and "toe room" beyond the range of values that represents the nominal black-to-white signal range. Moreover, 16-bit and 32-bit floating point color component codings are supported in JPEG XR. In these cases the image is interpreted as floating point data, although the JPEG XR encoding and decoding steps are all performed using only integer operations (to simplify the compression processing). The shared-exponent floating point color format known as RGBE (Radiance) is also supported, enabling more