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RE: Timed Text Authoring Format - Distribution Format Exchange Pr ofile (DFXP) Streaming

From: Glenn A. Adams <gadams@xfsi.com>
Date: Tue, 29 Mar 2005 09:52:48 -0500
Message-ID: <7249D02C4D2DFD4D80F2E040E8CAF37C03C37C@longxuyen.xfsi.com>
To: <Johnb@screen.subtitling.com>
Cc: <public-tt@w3.org>
Since we don't (and won't) define a DFXP UA, it is up to whomever
defines a UA to determine whether user specified style sheets or
transforms may apply. In general, I don't see why they should not.

 

I'm not sure what you mean by "separate metadata for each language". You
can express whatever metadata you want at whatever granularity you wish
(since every content element can take meta children which can contain
arbitrary metadata constructs.

 

  _____  

From: Johnb@screen.subtitling.com [mailto:Johnb@screen.subtitling.com] 
Sent: Tuesday, March 29, 2005 10:05 AM
To: shayes@microsoft.com; Glenn A. Adams
Cc: public-tt@w3.org
Subject: RE: Timed Text Authoring Format - Distribution Format Exchange
Pr ofile (DFXP) Streaming

 

Sean,

 

Hi...

 

This approach is one I am considering for conditional content ....
'watershed words'

 

I don't favour it for language selection because it doesn't address the
issue of having separate metadata for each language. I view that as
important since there may be rights issues (e.g. copyright and
distribution) that are on a **per language basis**.

 

For conditional content this works quite well, as it is trivial (in
concept) to modify the style definitions.... so taking your example and
twisting slightly gives.... (note: it's set for after 8:00pm :-)

 

<styling>

    <style id="before8pm" tts:display="none" />

    <style id="after8pm" tts:display="auto" />

</styling>

...

<div>

    <p>So I told him to <span style="before8pm">"Go away!"</span><span
style="after8pm">"Piss Off!"</span></p>

</div>

 

Note - I anticipate in **most** cases conditional content will be ...
inline...

 

Of course - this solution works if we anticipate an interpretation of
the DFXP pre-delivery. It does not work for DFXP as a delivery format
UNLESS it is assumed that a UA can apply a user defined stylesheet to a
DFXP document or otherwise modify the DFXP document prior to display
(Comments Glenn?)

 

regards 

John Birch

 

 -----Original Message-----
From: Sean Hayes [mailto:shayes@microsoft.com]
Sent: 29 March 2005 15:25
To: Johnb@screen.subtitling.com; gadams@xfsi.com
Cc: public-tt@w3.org
Subject: RE: Timed Text Authoring Format - Distribution Format Exchange
Pr ofile (DFXP) Streaming

	How about an approach like the following:

	 

	<styling>

	    <style id="lang1" tts:display="none" />

	    <style id="lang2" tts:display="auto" />

	    <style id="lang3" tts:display="none" />

	</styling>

	...

	<div>

	    <p style="lang1">Bonjour</p>

	    <p style="lang2">Ola</p>

	    <p style="lang3">Hello</p>

	</div>

	 

	Here, you only have to change the display property in the
selected language and you get the bits you need. The same approach
should work for watershed words, etc.

	 

	Sean.

	 

	
  _____  


	From: public-tt-request@w3.org [mailto:public-tt-request@w3.org]
On Behalf Of Johnb@screen.subtitling.com
	Sent: 29 March 2005 06:32
	To: gadams@xfsi.com; Johnb@screen.subtitling.com
	Cc: public-tt@w3.org
	Subject: RE: Timed Text Authoring Format - Distribution Format
Exchange Pr ofile (DFXP) Streaming

	 

	Glenn,

	 

	The 'problem' with your suggested approach **for me** is that
all of the parallel languages would share a common head section (which
contains the layout and styling elements). This would make combining
languages into a composite multi-language document diificult - imagine
if the language to be appended contains style references that match
existing ones. Further - extraction also becomes more complex, as it
would be necessary/desirable to reduce the head element to only those
element instances that are referenced by a specific language. Secondly -
since the div element cannot be nested, use of the div element to
separate parallel languages, as would be logical for my anticipated use,
would effectively remove the ability to use div for any other structural
purpose (such as separating program segments).

	 

	Using annotations for filtering content strikes me as a rather
'weak' approach to solving my requirement.... it also conflicts with
other potential uses for the role element - e.g. identification of the
'type' of text it annotates (dialogue, lyrics, description).... and any
profile using a 'ttm:role' based styling mechanism.

	 

	I think it more likely that it will be necessary to generate a
profile for DFXP, and probably a DFXP wrapper format to handle the
multi-language issue to satisfy my (and others) requirements.

	 

	regards

	John Birch

	 

	 

	-----Original Message-----
	From: Glenn A. Adams [mailto:gadams@xfsi.com]
	Sent: 29 March 2005 14:30
	To: Johnb@screen.subtitling.com
	Cc: public-tt@w3.org
	Subject: RE: Timed Text Authoring Format - Distribution Format
Exchange Pr ofile (DFXP) Streaming

		In point 1, I mean DFXP. You could, e.g., place parallel
languages in separate div, p, span elts, etc., although this is not a
recommended usage for interchange. Then you could use XSLT/XQuery, etc.,
between your archive and over-the-air inserter (where presumably it
would be transformed into some final distribution format, e.g., DVB
Subtitles). Also, you could do something similar for annotating content
to be filtered in the transform step, e.g., ttm:role="x-adult".

		 

		
  _____  


		From: Johnb@screen.subtitling.com
[mailto:Johnb@screen.subtitling.com] 
		Sent: Tuesday, March 29, 2005 8:41 AM
		To: Glenn A. Adams
		Cc: public-tt@w3.org
		Subject: RE: Timed Text Authoring Format - Distribution
Format Exchange Pr ofile (DFXP) Streaming

		 

		Hi Glenn,

		 

		I'm not sure I understand your response?

		 

		In point 1, do you mean AFXP? cf DFXP. Alternatively,
how would you suggest structuring a multi-language DFXP document?

		 

		w.r.t. point 2, I have perhaps created confusion by
referring to a timedtext stream. I did not intend to imply that the
content of that element was intended for streaming in the internet sense
of the word..... rather I used the term stream as analogous to 'thread'.

		 

		regards 

		John Birch. 

			-----Original Message-----
			From: Glenn A. Adams [mailto:gadams@xfsi.com]
			Sent: 29 March 2005 14:13
			To: Johnb@screen.subtitling.com
			Cc: public-tt@w3.org
			Subject: RE: Timed Text Authoring Format -
Distribution Format Exchange Pr ofile (DFXP) Streaming

			1.	In the main archive, you could have a
single DFXP document that combines languages and usages (adult/child),
and then use an XSLT transform (or XQuery) to select the portions
required for a "send to air" document. 
			2.	While the TTWG does consider
streamability to be a necessary property of DFXP, it drew the line at
actually defining a streaming form, which was considered out of scope;
however, there is nothing to prevent a future specification (either in
or out of W3C) from defining such a form. 

			 

			G.

			 

			
  _____  


			From: Johnb@screen.subtitling.com
[mailto:Johnb@screen.subtitling.com] 
			Sent: Tuesday, March 29, 2005 7:22 AM
			To: Glenn A. Adams
			Cc: public-tt@w3.org
			Subject: RE: Timed Text Authoring Format -
Distribution Format Exchange Pr ofile (DFXP) Streaming

			 

			Glenn,

			 

			Current practice for subtitling in broadcast TV
is to hold an archive of all subtitle files for all material that has
been, will be, or may be broadcast.

			This can amount to many tens of thousands of
files. (David can probably give you a number for the BBCs archive!)

			 

			Current practice (at least for us) is to combine
all individual language files into a single multi-language package for a
given program.

			 

			So, subtitle files are originated by subtitlers
in a single language - and transferred, QA'd and then typically combined
into a multi-language 'air' file.

			These 'air' files are then held in a 'subtitle
archive' that can be accessed by the insertion systems when station
automation requests the playout of a particular piece of material.
Typically for a European operation there may be on average 4-6 languages
present in each multi-language file (although we have systems with many
more langauges per channel than this).

			 

			There are many models being discussed within the
ad-hoc committee, doubtless there will be a transition interval where
DFXP content is held externally to the media content. Indeed it may be
(for operational reasons) that the combined MXF/AAF with subtitles
incorporated internally is only used as a 'between broadcaster' format -
not as a near to air format.

			 

			So, a nominally single language DFXP could
result in a proliferation of files (probably by a factor of 4 - 8) for
broadcasters. Note - we are assuming that insertion equipment will move
across to using DFXP **directly** here.

			 

			By onerous, there are implementation issues to
consider. The increase in the number of files creates a subtle problem.
The files have to be referred to by the automation equipment, changing
from a multi-lingual system to a single language per file concept means
that either the automation system has to send multiple demands to the
insertion equipment (for each language) - changing the whole concept of
the automation interface, or the insertion equipment has to determine
which individual DFXP files constitute the fileset for a given material
reference. It is unlikely that many broadcasters will wish to make
changes to station automation... this is VERY much an area of "If It
Aint Broke Don't Fix It" - by which I mean there is a strong resistance
to messing with such a critical aspect of a broadcasters operation.

			 

			So we can fairly safely assume that the
insertion system will need to expand a single material reference into a
fileset. This in itself doesn't sound to difficult until you consider
that the system will need to be created and maintained by human
operators!. At present there is one point of potential failure - the
appending of a new subtitle language 'stream' into the archive. With the
multiple files approach dictated by DFXP's limitation to single language
-  more opportunies can arise for problems.

			 

			So - single language DFXP increases the number
of files to handle (by perhaps a factor of 4 - 8), and the omission of a
conditional content mechanism may multiply that again....

			 

			BTW 

			Is there any practical reason why DFXP couldn't
be multi-stream, or is it simply a philosophical issue? What (apart from
the schema) prevents a DFXP document having effectively more than one
instance of the tt element structure?

			 

			e.g. (introduction of element tts "timedtext
stream")

			 

			<tt xmlns="http://www.w3.org/2004/11/ttaf1">
			<tts xml:lang="fr-fr">
			  <head>
			    <meta/>
			    <styling/>
			    <layout/>
			  </head>
			  <body/>
			</tts>

			<tts xml:lang="en-uk">
			  <head>
			    <meta/>
			    <styling/>
			    <layout/>
			  </head>
			  <body/>
			</tts>

			<tts xml:lang="en-uk-caption">
			  <head>
			    <meta/>
			    <styling/>
			    <layout/>
			  </head>
			  <body/>
			</tts>

			</tt>

			 

			regards 

			John Birch.

			 

			 -----Original Message-----
			From: Glenn A. Adams [mailto:gadams@xfsi.com]
			Sent: 29 March 2005 12:28
			To: Johnb@screen.subtitling.com
			Cc: public-tt@w3.org
			Subject: RE: Timed Text Authoring Format -
Distribution Format Exchange Pr ofile (DFXP) Streaming

				Could you describe what you mean by
"subtitle archive" and "onerous to require ..."?

				 

				
  _____  


				From: Johnb@screen.subtitling.com
[mailto:Johnb@screen.subtitling.com] 
				Sent: Tuesday, March 29, 2005 3:47 AM
				To: Glenn A. Adams;
russ.wood@softel.co.uk; public-tt@w3.org
				Subject: RE: Timed Text Authoring Format
- Distribution Format Exchange Pr ofile (DFXP) Streaming

				 

				Glenn,

				 

				An issue that was discussed recently at
the AAF/MXF EBU ad-hoc subtitle commitee....

				 

				While the generation of multiple DFXP
'files' for individual languages is an acceptable solution, I feel there
may yet be a requirement for a 'lightweight' conditional content
mechanism. The specific example I have in mind is to support the concept
of viewing 'watersheds' - i.e. content unsuitable for minors.

				In this case the majority of a subtitle
file would be suitable for all viewers - but the odd word or phrase may
be 'sanitised' for pre watershed (e.g. 8.00pm) airings of the programme.
It would be onerous to require a subtitle archive to retain multiple
copies of content to cater for just the alteration of one of two words
in a 1300 line subtitle file. Is there any possibility of introducing a
conditional content facuility to DFXP that would support this kind of
minor use?

				 

				A second use of this mechanism, which
might be a stretch too far, is to support subtitle files that can be
used as captions (i.e. near verbatim + sound cues) or as subtitles. In
this case the conditional content may be the 'sound cues' and possibly
the replacement of some of the subtitle lines with less accurate (but
more concise!) translations.

				 

				best regards 

				John B.

				-----Original Message-----
				From: Glenn A. Adams
[mailto:gadams@xfsi.com]
				Sent: 26 March 2005 05:47
				To: Russ Wood; public-tt@w3.org
				Subject: RE: Timed Text Authoring Format
- Distribution Format Exchange Profile (DFXP) Streaming

				DFXP supports general use of xml:lang
attribute in order to (1) specify a default language for document
instance and (2) to annotation language of nested content. It is up to
the author to decide how to use this mechanism. For example, an author
could potentially specify different <div/> elements using different
languages, or different <p/> elements, etc. Nonetheless, the intention
is not to explicitly support in DFXP conditional content selection based
on preferred language. In contrast, conditional content selection will
be supported in AFXP. The intent with DFXP is to have already made all
conditional selections prior to transmitting/exchanging in DFXP format.
This means that if an AFXP document supports course granular conditional
selection between parallel language representations, then one may
produce multiple DFXP document instances from a single AFXP document
instance, by enumerating over the condional parameter space (of which
each permutation may produce a distinct DFXP document instance).

				 

				Regards,

				Glenn

				 

				
  _____  


				From: Russ Wood
[mailto:russ.wood@softel.co.uk] 
				Sent: Monday, March 21, 2005 5:36 AM
				To: public-tt@w3.org
				Subject: RE: Timed Text Authoring Format
- Distribution Format Exchange Pr ofile (DFXP) Streaming

				 

				3) I don't see a problem with allowing
different languages in the same document but amalgamating different
language files at run time is not difficult.

				 
Received on Tuesday, 29 March 2005 14:52:52 GMT

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