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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 09:23:21 -0500
Message-ID: <7249D02C4D2DFD4D80F2E040E8CAF37C03C37B@longxuyen.xfsi.com>
To: <Johnb@screen.subtitling.com>
Cc: <public-tt@w3.org>
Keep in mind that you can introduce non-standard attributes and elements
in different namespaces, and you can ascribe these with semantics that
meets your deployment needs. You can combine these with an XSLT/XQuery
transform stage to achieve powerful and flexible mappings from your
"archive" to your final delivery forms.

 

Keep in mind also that DFXP is intended to be explicitly simpler than
some of the features you seem to ask from it. Our original goal was to
simply capture an essential intersection of the union of SAMI, RealText,
QuickText, and 3GPP TT. I believe we have accomplished that plus some.
We need to ensure that feature creep does not prevent us from
establishing this important baseline upon which other profiles can be
profitably constructed.

 

G.

 

  _____  

From: Johnb@screen.subtitling.com [mailto:Johnb@screen.subtitling.com] 
Sent: Tuesday, March 29, 2005 9:32 AM
To: Glenn A. Adams; 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 14:23:32 GMT

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