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Response to SMIL 2.1Last Call comment: 2005JanMar/0015.html

From: Thierry MICHEL <tmichel@w3.org>
Date: Thu, 03 Mar 2005 19:03:35 +0100
Message-ID: <42275177.6070903@w3.org>
To: angwin@uk.ibm.com, www-smil@w3.org

The W3C SYMM thank you for your comments on SMIL 2.1 sent    

    * Sent: mer. 23/02/2005 15:49
    * Archived:
      http://lists.w3.org/Archives/Public/www-smil/2005JanMar/0015.html
      <http://lists.w3.org/Archives/Public/www-smil/2005JanMar/0004.html>
    * Issue 5: Liaison to W3C Re SMIL 2.1 (Mobile Application
      Environment Group of the Open Mobile Alliance)


SYMM WG has the following responses to these comments:

W3C SYMM thanks members of OMA's Mobile Application Environment (MAE) group, a subgroup of the Browsing and Content Working Group (BAC) for their comments on SMIL 2.1. SYMM WG has the following responses to these comments:

a) section 14.3.4 "Content Control Modules"

SMIL 2.1 is intended to be used for many services in addition to 
Multimedia Messaging Service (MMS), for example 
multimedia presentation that are downloadable from network servers and presentations 
distributed via CD-ROM/DVD. Therefore, SMIL 2.1 should not include guidelines 
on what kinds of references to media objects should be allowed from a SMIL presentation
in the special case of the MMS. 
Furthermore, pls notice that a SMIL player is not required to actually prefetch any 
media content to claim support for SMIL 2.1 PrefetchControl module.


b) Section 7.3 SMIL Basic Media Module:

Making the requested change would break compatibility with SMIL 2.0 and SMIL 1.0.
This would not be acceptable.

One way how a SMIL player implementation can circumvent the described problem is to
resolve the MIME type of the media object before creating a specialized rendering 
object. In the case of MMS the MIME type of the media
object is available from the header of the multipart MIME structure.


As part of its work on SMIL Next Generation the WG considers adding mechanisms that 
would allow a SMIL content authors to specify which selected parts of a compount audio-visual 
stream should be presented. However, to remain backward compatible the existing elements
of MediaObjects module can not be used for this. E.g. <audio src="compount-stream.3pg" />
could not be used to define that only an audio track of an audio-visual stream should be 
rendered. Instead, the SYMM WG will need to invent new markup for this purpose.


Please acknowledge this SYMM WG response by replying to this mail and 
copying the SMIL public mailing list: www-smil@w3.org

Best,

On behalf of the SYMM WG,
Thierry MICHEL
SYMM WG Team contact.
Received on Thursday, 3 March 2005 18:03:48 GMT

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