5 Formats for Continuous Media

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

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

In order to guarantee a minimum support and compatibility between IMS Messaging and Presence Service capable terminals and MMS capable terminals that offer support of continuous media formats (section 5) and media synchronisation and scene description (see section 6), IMS Messaging User Agent and IMS Presence User Agent supporting specific media types should in addition to formats listed in section 4 of this document comply with the following selection of media formats:

5.1 Speech

For IMS terminals supporting speech, the AMR codec shall be supported for narrow-band speech [26][40][41][42].

The AMR wideband speech codec [27] [43][44][45] shall be supported when wideband speech working at 16 kHz sampling frequency is supported.

When using speech media type alone, AMR or AMR-WB data stored according to the file format specified in [32] should be supported. The mandatory format is defined in clause 5.4.

Multi-channel sessions shall not be used.

5.2 Audio

For IMS terminals supporting audio, one or both of the following two audio codecs should be supported:

– Enhanced aacPlus [49][50][51]

– Extended AMR-WB [46][47][45]

There is no requirement that a terminal supporting decoding by one of the codecs shall also support encoding by that codec.

Specifically, based on the audio codec selection test results Extended AMR-WB is strong for the scenarios marked with blue, Enhanced aacPlus is strong for the scenarios marked with orange, and both are strong for the scenarios marked with green colour in the table below:

Content type Bit rate	Music	Speech over Music	Speech between Music	Speech
14 kbps mono
18 kbps stereo
24 kbps stereo
24 kbps mono
32 kbps stereo
48 kbps stereo

More recent information on the performance of the codecs based on more recent versions of the codecs can be found in TR 26.936 [62].

Enhanced aacPlus decoder is also able to decode MPEG-4 AAC LC content.

Extended AMR-WB decoder is also able to decode AMR-WB content.

In addition, MPEG-4 AAC Low Complexity and MPEG-4 AAC Long Term Prediction object types [19] may be supported. The maximum sampling rate to be supported by the decoder is 48 kHz. The channel configurations to be supported are mono (1/0) and stereo (2/0).

5.3 Video

For IMS terminals supporting video, media codecs are specified in TS 26.114 [63], clause 5.2.2. The video codecs are the same as for MTSI clients in terminals.

5.4 File Format for video and associated speech/audio media types

To ensure interoperability for the transport of video and associated speech/audio in an IMS Messaging and Presence client, the 3GPP file format with Basic profile shall be supported.

The usage of the 3GPP file format shall follow the technical specifications and the implementation guidelines specified in TS 26.244 [33].

5.5 Synthetic audio

For IMS terminals supporting synthetic audio, the Scalable Polyphony MIDI (SP-MIDI) content format defined in Scalable Polyphony MIDI Specification [28] and the device requirements defined in Scalable Polyphony MIDI Device 5-to-24 Note Profile for 3GPP [29] should be supported.

SP-MIDI content is delivered in the structure specified in Standard MIDI Files 1.0 [31], either in format 0 or format 1.

In addition the Mobile DLS instrument format defined in [38] and the Mobile XMF content format defined in [39] should be supported.

A MSS client supporting Mobile DLS shall meet the minimum device requirements defined in [38] in section 1.3 and the requirements for the common part of the synthesizer voice as defined in [38] in sections 1.2.1.2. If Mobile DLS is supported, wavetables encoded with the G.711 A-law codec (wFormatTag value 0x0006, as defined in [38]) shall also be supported. The optional group of processing blocks as defined in [38] may be supported. Mobile DLS resources are delivered either in the file format defined in [38], or within Mobile XMF as defined in [39]. For Mobile DLS files delivered outside of Mobile XMF, the loading application should unload Mobile DLS instruments so that the sound bank required by the SP-MIDI profile [29] is not persistently altered by temporary loadings of Mobile DLS files.

Content that pairs Mobile DLS and SP-MIDI resources is delivered in the structure specified in Mobile XMF [39]. As defined in [39], a Mobile XMF file shall contain one SP-MIDI SMF file and no more than one Mobile DLS file. MMS clients supporting Mobile XMF must not support any other resource types in the Mobile XMF file. Media handling behaviours for the SP-MIDI SMF and Mobile DLS resources contained within Mobile XMF are defined in [39].

5.6 Vector graphics

For IMS terminals supporting 2D vector graphics, the Scalable Vector Graphics (SVG) Tiny 1.2 format [20][21] and ECMAScript [54] shall be supported.

NOTE 1: The compression format for SVG content is GZIP [35], in accordance with the SVG specification [20].

NOTE 2: Only media formats supported by IMS Messaging and Presence, as specified in clauses 4 and 5 of this specification, shall be used. MMS Messaging and Presence clients do not support the Ogg Vorbis format.

NOTE 3: Content creators of SVG Tiny 1.2 for IMS Messaging and Presence clients are strongly recommended to follow the content creation guidelines provided for PSS clients in Annex L of [14].

NOTE 4: If SVG Tiny 1.2 will not be published within a reasonable timeframe, the decision to adopt SVG Tiny 1.2 in favour of SVG Tiny 1.1 may be reconsidered.