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Re: 3GPP-T-WG3 codecs

From: Philipp Hoschka <ph@w3.org>
Date: Thu, 07 Dec 2000 14:39:42 -0500
Message-ID: <3A2FE77E.801A7721@w3.org>
To: discuss@apps.ietf.org, www-smil@w3.org
Patrick,

FWIW, there is a set of "recommended" codecs in the SMIL 2.0
draft of W3C, and I'm happy to explain why we chose those, if
needed:

http://www.w3.org/TR/2000/WD-smil20-20000921/smil20-profile.html#BaselineFormatsNS

> Widely Supported MIME Types
> 
>    This section is informative.
> 
>    The members of the W3C SYMM Working Group believe that the following
>    MIME types will be widely supported by SMIL players:
>      * audio/basic [592][MIME-2]
>      * image/png ([593][PNG-MIME], [594][PNG-REC])
>      * image/jpeg ([595][MIME-2], [596][JFIF])
>    Implementers of SMIL players should thus strive to provide support for
>    each of these types. Note, however, that this section is
>    non-normative, and that support for these MIME types is not a
>    precondition for conformance to this specification.
> 
>    Authors are encouraged to encode media objects using one of the widely
>    supported MIME types whenever possible. This will ensure that their
>    SMIL documents can be played back by a wide range of SMIL players.
> 
>    If authors use a MIME type that is not in the list of widely supported
>    types, they should provide an alternative version encoded using a
>    baseline format. This can be achieved by using a switch element as
>    shown in the following example:
> <switch>
>   <audio src="non-baseline-format-object" />
>   <audio src="baseline-format-object" />
> </switch>
> 
>    In this example, a player that supports the non-baseline format will
>    play the first audio media object, and a player that does not support
>    the non-baseline format will play the second media object.

In general, I'm a bit confused about the request - why would the 
IETF have to comment on the minimal set of codecs in a format
defined by another organisation ? This would make sense if the
goal is to define a minimal set of codecs that need to be supported
by MIME mail readers, but otherwise, I don't see the point - am
I missing something ?

-Philipp

> 3GPP-T-WG3 codecs
> 
> From: Patrik Fältström (paf@cisco.com)
> Date: Thu, Nov 30 2000
> 
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>   ------------------------------------------------------------------------
> 
> Message-Id: <p05100543b64c4580118a@[10.0.1.28]>
> Date: Thu, 30 Nov 2000 18:58:56 +0100
> To: discuss@apps.ietf.org
> From: Patrik Fältström  <paf@cisco.com>
> 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
> 
> --
> 
>   ------------------------------------------------------------------------
> 
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Received on Thursday, 7 December 2000 14:43:50 UTC

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