(registered 2019-03-28, last updated 2019-03-28)

Media type name: image

Subtype name: jxr

Required parameters: none

Optional parameters: none

Encoding considerations: files are binary and should be transmitted in
a suitable encoding without CR/LF conversion, 7-bit stripping
etc.; base64 is a suitable encoding.

Security considerations: The conveyed coded image files use a
structure that can store image data, metadata corresponding to
this image data, and other user-defined data. The data files have an extensible
structure, so that it is theoretically possible that metadata
fields could be defined in the future that could be used to
induce particular actions on the part of the recipient, thus
presenting additional security risks, but this type of
capability is currently not supported in the current referenced
specifications.

Interoperability considerations: JPEG XR coded image files can conform
to one of several profiles and levels of capabilities (as
specified in Annex B of Rec. ITU-T T.832 and ISO/IEC 29199-2) – 
not all of which may be supported by a receiving
decoder. As a result, implementations may attempt to decode and
display an encoded JPEG XR image only to determine that the
image cannot be rendered either partially or in full.

Published specification:
Rec. ITU-T T.832 and ISO/IEC 29199-2,
Information technology – JPEG XR image coding system – Image
coding specification

Applications that use this media type: Imaging, fax, messaging and
multimedia.

Fragment identifier considerations: N/A

Additional information:

Deprecated alias names for this type: N/A

Magic number(s):
Data begins with a FILE_HEADER( ) data structure, which begins 
with a FIXED_FILE_HEADER_II_2BYTES field equal to 0x4949, followed
by a FIXED_FILE_HEADER_0XBC_BYTE field equal to 0xBC,
followed by a FILE_VERSION_ID which is equal to 1 for the
current version of the Recommendation and International
Standard (with other values reserved for future use, as
modified in additional parts or amendments, by ITU-T or
ISO/IEC).

Within the payload data, JPEG XR IMAGE_HEADER( ) data
structures begin with a GDI_SIGNATURE, which is a 64-bit
syntax element that has the value 0x574D50484F544F00 that
corresponds to "WMPHOTO" using the UTF-8 character set
encoding specified in Annex D of ISO/IEC 10646, followed by a
byte equal to 0.

File extension(s): jxr

Person and email address to contact for further information:
ISO/IEC JTC 1/SC 29/WG 1 Convenor
(sc29-sec&itscj.ipsj.or.jp)

Intended usage: COMMON

Restrictions on usage: N/A

Author: ITU-T and ISO/IEC JTC 1

Change controller: ITU-T and ISO/IEC JTC 1

Provisional registration? (standards tree only): No

Other general information: It should be noted
that selected metadata fields may encompass information partly
intended to protect the image against unauthorized use or
distribution. In this case, the intention may be that alteration
or removal of the data in the fields would be treated as an
offence. Metadata fields may also contain information about the
source of the image content.