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RE: 3GPP-T-WG3 codecs

From: Glenn Parsons <gparsons@nortelnetworks.com>
Date: Thu, 30 Nov 2000 13:16:32 -0600
Message-ID: <488891341182D4118A870000F80822E782B7AB@zcard00p.ca.nortel.com>
To: discuss@apps.ietf.org, "'IETF VPIM List'" <vpim@lists.neystadt.org>
Cc: 'Patrik Fältström' <paf@cisco.com>

I would suggest that the members of the VPIM WG have interest in this and
may be interested in this process (I can say that I am).  I think the point
of this is to define a minimum set of codecs for multimedia messaging for
3G.  We have been doing the same for unified messaging in VPIM & IVM (though
we have just been talking about voice and fax).  It is interesting to note
that with IVM we originally had support for numerous codecs suggested as the
baseline, but after discussion we reduced it to one.

I am intrigued that they list the WAV header format as baseline but do not
identify any of its 300+ codecs.  

I am not surprised they want to use their AMR/EFR codec -- but I'd like to
know how different it is from GSM 6.10 (of which a variant is the current
proposed baseline for IVM).  I believe AMR/EFR for 3G is the same as GSM
6.90.  And, of course, this is different from the North American wireless
codecs :-(

I am curious why they don't list G.711 mu-law as one of the audio codecs.
It would seem that if we are getting into transcoding, that one would want
to list the lowest common denominator.   


> ----------
> From: 	Patrik Fältström
> Sent: 	Thursday, November 30, 2000 12:58 pm
> To: 	discuss@apps.ietf.org
> Subject: 	3GPP-T-WG3 codecs
> I need people interested in the are of codecs. Can someone help with 
> the following request?
> Let me know if you are interested (or know someone which are interested).
>     Patrik
>     Co-Area Director, Applications Area
> Date: Wednesday, 29 November, 2000 15:06 -0800
> From: "Leuca, Ileana" <ileana.leuca@attws.com>
> To: "'sob@harvard.edu'" <sob@harvard.edu>
> Subject: 3GPP-T-WG3 codecs
> Scott,
> the 3GPP-T2-WG3 defines the minimum set of supported formats for
> Multimedia Messaging Services.
> Please help to find an IETF person(s) to be included in the
> process of standardizing the minimum set of codex for audio,
> video and image types.
> In summary the following text is proposed today:
> ==========================================
> Multiple media elements shall be combined into a composite
> single MM using MIME multipart format as defined in RFC 2046
> [x]. The media type of a single MM 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 multimedia messaging capable terminals, the following
> media formats shall be at least supported.
> Suggested formats or codecs for media type Audio:
> - AMR / EFR; organised in octet format as specified in 3G TS
> 26.101 and 3G TS 26.101
> - MP3
> - MIDI
> - WAV
> Suggested formats or codecs for media type Image:
> - JPEG
> - GIF 89a .
> Suggested formats or codecs for media type Video:
> - MPEG 4 (Visual Simple Profile, Level 1)
> - ITU-T H.263
> - Quicktime
> Minimum set of supported media shall support type Text formats.
> Any character encoding (charset) that contains a subset of the
> logical characters in Unicode [7] shall be used (e.g. US-ASCII
> [8], ISO-8859-1[9], UTF-8[10], Shift_JIS, etc.).
> Unrecognised subtypes of "text" shall be treated as subtype
> "plain" as long as the MIME implementation knows how to handle
> the charset. Any other unrecognised subtype and unrecognised
> charset shall be treated as "application/octet - stream".
> ================================================================
> ============ ==
> thanks,
> ileana
> -- 
Received on Thursday, 30 November 2000 14:58:18 UTC

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