Re: SMIL (was Re: TO DO'S FOR 1.2.1)

Sorry, "static" was the wrong word. Was trying to get at whether or not 
there are different techniques needed if the content that is being 
captioned is live vs. prerecorded.

Christophe points out that the protocol is different - RTSP for 
streaming vs. HTTP or TCP for prerecorded, but I'm not sure that this is 
a concern for us since streaming servers are often used to deliver 
prerecorded content as well as live content.

Perhaps the only difference is in the hardware (what happens between the 
captioner's keyboard and the video encoder that outputs the content to 
the streaming server).

I'm fine with leaving them as they appear in the wiki.

-Ben


Gregg Vanderheiden wrote:
> What are static captions? 
> 
> 
>  
> Gregg
> 
>  -- ------------------------------ 
> Gregg C Vanderheiden Ph.D. 
> Professor - Ind. Engr. & BioMed Engr.
> Director - Trace R & D Center 
> University of Wisconsin-Madison 
> 
> 
> -----Original Message-----
> From: public-wcag-teama-request@w3.org
> [mailto:public-wcag-teama-request@w3.org] On Behalf Of Christophe Strobbe
> Sent: Tuesday, January 10, 2006 12:57 PM
> To: public-wcag-teama@w3.org
> Subject: SMIL (was Re: TO DO'S FOR 1.2.1)
> 
> 
> 
> At 18:18 9/01/2006, Ben Caldwell wrote:
> <blockquote>
> (...)
> 1.2.3: I've added the SMIL techniques for 1.2.1 to 1.2.3 in the wiki per
> Gregg's request. However, I'm not sure that the techniques would be the same
> for static vs. real-time captions in SMIL? Any SMIL experts on Team A that
> can help?
> (...)
> </blockquote>
> 
> In the absence of SMIL experts, I consulted "SMIL: Adding Multimedia to the
> Web" by Tim Kennedy and Mary Slowinski (SAMS, 2002; see also
> http://www.smilbook.com/).
> For a prerecorded video, you do "pseudostreaming" or "progressive download" 
> over HTTP and TCP, while live video requires true streaming with a streaming
> server and a streaming protocol over UDP (instead of TCP). The book has
> nothing to say about how you work with resources from a streaming server.
> However, there is a SMIL example at http://open4all.info/ossa/_SMIL. In the
> SMIL file, you need a correct link to the stream on the server, which, in
> this example, talks RTSP.
> There's also some information at
> http://service.real.com/help/library/guides/production8/htmfiles/live.htm.
> As far as I can tell, the real challenge is creating those streams and
> getting the captions synchronized.
> 
> Regards,
> 
> Christophe
> 
>

Received on Tuesday, 10 January 2006 20:24:41 UTC