faithful storage of high-dynamic-range (HDR) images. In addition to RGB and CMYK formats, JPEG XR also supports grayscale and multi-channel color encodings with an arbitrary number of channels. The color representations, in most cases, are transformed to an internal color representation. The transformation is entirely reversible, so that this color transformation step does not introduce distortion and thus lossless coding modes can be supported. Transparency map support An alpha channel may be present to represent transparency, so that alpha blending overlay capability is enabled. Compressed-domain image modification In JPEG XR, full decoding of the image is unnecessary for converting an image from a lossless to lossy encoding, reducing the fidelity of a lossy encoding, or reducing the encoded image resolution. Full decoding is also unnecessary for certain editing operations such as cropping, horizontal or vertical flips, or cardinal rotations. The tile structure for access to image regions can also be changed without full decoding and without introducing distortion. Metadata support A JPEG XR image file may optionally contain an embedded ICC color profile, to achieve consistent color representation across multiple devices. Exif and XMP metadata formats are also supported. Container format One file container format that can be used to store JPEG XR image data is specified in Annex A of the JPEG XR standard. It is a TIFF-like format using a table of Image File Directory (IFD) tags. A JPEG XR file contains image data, optional alpha channel data, metadata, optional XMP metadata stored as RDF/XML, and optional Exif metadata, in IFD tags. The image data is a contiguous self-contained chunk of data. The optional alpha channel, if present, can be compressed as a separate image record, enabling decoding of the image data independently of transparency data in applications which do not support transparency. (Alternatively, JPEG XR also supports an "interleaved" alpha channel format in which the alpha channel data is encoded together with the other image data in a single compressed codestream.) Being TIFF-based, this format inherits all of the limitations of the TIFF format including the 4 GB file-size limit, which according to the HD Photo specification "will be addressed in a future update". New work has been started in the JPEG committee to enable the use of JPEG XR image coding within the JPX file storage format — enabling use of the JPIP protocol, which allows interactive browsing of networked images. Additionally, a Motion JPEG XR