RE: new issue? dfxp and language selection

It's a good explanation, but I fear I'm not quite getting my point across.

Two selection scenarios are common in subtitling.

A) target audience language selection. Probably at a level immediately below body level between multiple 'functionally equivalent' yet language differentiated divs.
B) Removal of inline content because of user preference. For example, in a movie with hard-of-hearing subtitles, a user may wish to turn off the subtitles pertaining to sound effects, but retain those relating to speech. Note: this can be done with current spec using ttm:role attribute. 

I agree that DFXP should include a marker that makes an explicit statement about intent. 
E.g. This content is intended for french speakers. 
Or perhaps go further... E.g. This content is intended for french speakers who are also deaf (although this can be finessed using the role attribute).

I agree with Sean that I think that the same type of selection that might be achieved by language matching and switch constructs can be achieved by processing - PROVIDED that sufficient markup exists in the document to identify content with sufficient granularity.

So my suggestion would be

   <sequence ttm:lang="fr" title="Titre en français">
     <p ttm:role="sound">FANFARE!</p>
     <p>Ce texte est en français.</p>
     <p ttm:lang="fr-CA">Ce texte est en québécquois.</p>
   </sequence> 

   <sequence ttm:lang="en" title="Title in English">
     <p ttm:role="sound">TYRE SCREECH!</p>
     <p>Quick! Put the body in the boot!</p>
     <p ttm:lang="en-US">Quick! Put the body in the trunk!</p>
   </sequence> 

BUT what is interesting here is that the two text strings (excluding the sound effect representation) ARE equivalents. 
What is certain is that BOTH should NOT be displayed. Perhaps some form of alt. markup is required :-)

BTW Of course I'm assuming fr = fr-fr and en = en-en :-)

Best regards,

John


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-----Original Message-----
From: Daniel Weck [mailto:daniel.weck@gmail.com] 
Sent: 04 December 2008 16:09
To: John Birch
Cc: Hayes Sean; Glenn A. Adams; Public TTWG List
Subject: Re: new issue? dfxp and language selection


On 4 Dec 2008, at 15:07, John Birch wrote:
> JB>> Generic XML can be processed using internal content and external
> criteria. I personally view switches as being a way of pre-coding 
> common processing operations - but I view it as ~dangerous~ to only 
> allow those pre-coded choices to be made in order to remain 
> 'conformant'.

I see what you mean: you see it as some kind of "anti-pattern", in reference to software development :)

Now, let's consider this fictitious, yet relevant sample:

<text xml:lang="en">
   <sequence xml:lang="fr" title="Titre en français">
     <p>Texte en français.</p>
     <p xml:lang="fr-CA">Texte en québécquois.</p>
     <p xml:lang="en-GB">Text in British English.</p>
   </sequence>
   <p>Text in (unspecified) English.</p> </text>

If "xml:lang" was to be processed by user-agents as a content selection criteria, there would be a number of issues:

1) Clearly, content selection wasn't the original intent of the author. It is obvious that here, the "xml:lang" attributes decorate the elements to merely indicate the locale of the content. With the above XML snippet, XPath and the lang() function can be used, for example, pre-process (e.g. XSLT transform) or to dynamically alter the content (e.g. "highlight any English text in bright yellow"). This kind of processing made by the user-agent seems perfectly reasonable.  
On the other hand, my instinctive subjective assumption is that content pruning is not the desired goal. To remove this ambiguity, the TT/DFXP distribution format for captions should provide more than just a hint, it should clearly specify the intent (IMHO). This would promote re-using content across multiple processors.

2) The "xml:lang" attribute applies to an entire XML fragment, until it is overridden. In a content selection scenario, this nesting ability prompts a number of questions. For example, what happens if the user-agent locale is set to "fr": should the top-level "text"  
element be totally ignored/pruned, or should the "sequence" be processed and the following "p" ignored ? My personal systematic / scientific mind is in favor of the former, but I know authors who would "feel" that the latter is right.

3) What about more complex selection criteria ? Let's say that I want to mark a piece of text as "suitable for all flavors of French expect
Canadian": using a (fictitious) 'matchLanguage' attribute, I could write matchLanguage="fr AND NOT fr-CA". Note: the coma-separated values in the SMIL systemLanguage attribute represent a OR boolean logic, so there are limitations in the selection model.

4) What about a fallback logic, so that if no suitable language is matched, then a specific XML fragment is enabled ? In SMIL, the 'switch' offers this mechanism, which enriches the default selection model based on the combinatory attribute value.

I feel that a proper "content control" mechanism would address these concerns. Otherwise, I am not convinced that TT/DFXP will sufficiently eliminate ambiguities that user-agent implementors and content authors (or developers of production tools) will face, and I would recommend to clearly state that xml:lang is not designed for content selection, and that to be reflected in user-agent conformance guidelines.

> JB>> If we did not have existent implementations then I would be
> proposing two language attributes. One to allow a language specific 
> instance of a DFXP document (i.e. the true xml:lang sense) and another 
> - perhaps ttm:lang, to define the language used in sections of the 
> document.

The "xml:lang" attribute from XML 1.0 and 1.1 can do both scenarios you mention. "xml:lang" is not meant to be limited to the document instance as far as I know. The "lang" versus "xml:lang" mess has been fixed in XHTML 1.1 IIRC, isn't that a good trend to follow ?

Regards, Dan


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Received on Thursday, 4 December 2008 16:51:49 UTC