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RE: TT and subtitling/captioning - temporal flow of content

From: Glenn A. Adams <glenn@xfsi.com>
Date: Thu, 7 Aug 2003 11:43:27 -0400
Message-ID: <7249D02C4D2DFD4D80F2E040E8CAF37C03BCBD@longxuyen.xfsi.com>
To: <Johnb@screen.subtitling.com>
Cc: <public-tt@w3.org>
I'm afraid I'm still not following your description. Could you try to put together a example of what you mean using some of the vocabulary we have been describing? If you could create some images of how it would look over time, then I could understand better.



	From: Johnb@screen.subtitling.com [mailto:Johnb@screen.subtitling.com] 
	Sent: Thursday, August 07, 2003 11:40 AM
	To: Glenn A. Adams
	Cc: public-tt@w3.org
	Tackling just the temporal flow issue - I'm still digesting the style separation feedback.....

		A second question.... 

			It would be desirable for TT (at least IMHO) to include mechanisms for describing the temporal breaking of content. 
			What I am thinking of is a document that does not describe explicitly the timing for all of the content 
			- but rather describes that X amount of content fits into a box of size Y over a time period of Z. 
			Now if the content X is too large for box Y - how does the content get over(?)flowed in a 'temporal sense' through the box.  

			I'm not sure I'm following your scenario here. Are you saying you want individual characters, words, lines, etc. to appear in box Y over time, and do so without explicitly timing each unit?
			[JB> ] That's exactly it. No explicit timing - but an overall timing. For example timing is specified for a paragraph of text (multiple lines) to be 'rendered' into a nominally single line region over that time period.

			If so, I can see some possible problems, such as (1) needing to specify the granularity of content to be timed (i.e., character, word, etc.); (2) which would entail the need to formally specify how to subdivide content lacking markup into such units.
			[JB> ] Yes - it would - but this is what I see as part of the essence of timed text - a description of the behaviour of text over time.

			While this might make the content of a TT-AF file smaller,
			[JB> ] This isn't a size of file issue - rather it's a usability issue. By being able to specify how you want the user agent to react in situations of overflow - by spreading the text temporally cf (as well as) the CSS scroll / marquee concepts, I see the following advantages:

			It allows a faster authoring of content.

			It also potentially allows the creation of style templates that work more universally for text - they need not be so tied to specific text.

			A user agent that is able to take the role of distributing text over time would produce more consistent results.

			The translation of one langauge to another need not involve a 'knife and fork' re-edit of the file contents.

			it would also be possible to do this by animating the visibility property of individual units explicitly, making decisions about what constitute units at authoring time, e.g.,
			[JB> ] Snip 'knife and fork' explicitly timed example.

			Yes but this example has explicit timing. If the text is modified in length - you have to modify the timing. Different language (or reading level)instances of a given text content will differ in length, yet in a subtitling scenario - and many others I suspect - they will be constrained to display within the same specific display period that cannot be extended. Ideally TT-Af would allow the modification (or substitution) of content without the explicit requirement to adjust the number of, and timing of multiple cue elements.

	John Birch 

	The views and opinions expressed are the author's own and do not necessarily 
	reflect the views and opinions of Screen Subtitling Systems Limited.  
Received on Thursday, 7 August 2003 11:43:29 UTC

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