4 Formats for Static Media

26.1413GPPIP Multimedia System (IMS) Messaging and PresenceMedia formats and codecsRelease 17TS

Multiple media elements shall be combined into a composite single IMS message using MIME multipart content type format as defined in RFC 2046 [25]. The media type of a single IMS message element shall be identified by its appropriate MIME type whereas the media format shall be indicated by its appropriate MIME subtype.

In order to guarantee a minimum support and compatibility between IMS Messaging and Presence Service capable terminals and OMA IMPS 1.1 capable terminals, IMS Messaging User Agent and IMS Presence User Agent supporting specific media types shall comply with the following selection of media formats:

4.1 Text

Plain text. Any character encoding (charset) that contains a subset of the logical characters in Unicode [2] shall be used (e.g. US-ASCII [3], ISO-8859-1 [4], UTF-8 [5], Shift_JIS, etc.).

Unrecognized subtypes of "text" shall be treated as subtype "plain" as long as the MIME implementation knows how to handle the charset. Any other unrecognized subtype and unrecognized charset shall be treated as "application/octet ‑ stream".

4.2 Still Image

For IMS terminals supporting still images, ISO/IEC JPEG [8] together with JFIF [9] shall be supported. The support for ISO/IEC JPEG only apply to the following two modes:

– mandatory: baseline DCT, non-differential, Huffman coding, as defined in table B.1, symbol ‘SOF0’ in [8];

– optional: progressive DCT, non-differential, Huffman coding, as defined in table B.1, symbol ‘SOF2’ [8].

For JPEG baseline DCT, EXIF compressed image file format should also be supported, as defined in [58]. In that case there is no requirement for the MMS Messaging and Presence client to interpret or present the EXIF parameters recorded in the file.

4.3 Bitmap Graphics

For IMS terminals, supporting bitmap graphics, the following bitmap graphics formats should be supported:

– GIF87a [15];

– GIF89a [16];

– PNG [17].