W3C home > Mailing lists > Public > public-tt@w3.org > February 2003

RE: TT and subtitling

From: <Johnb@screen.subtitling.com>
Date: Wed, 5 Feb 2003 09:43:17 -0000
Message-ID: <11E58A66B922D511AFB600A0244A722E093EA9@NTMAIL>
To: geoff_freed@wgbh.org
Cc: public-tt@w3.org

I wrote:
	>However these distinctions are IMHO far removed from the
requirements of a
	>TT standard - which should be to define an agnostic mechanism for
the timed
	>delivery of text. Using XML, tags to provide distinction between
the text
	>categories (for want of a better term) should be optional, but
undefined by
	>the standard. The TT standard should IMHO only **define** tags that
	>necessary for the temporal control of the display of text.

Geoff Freed wrote:
	>I'm not so sure we can get away with this.  There are examples
today of multi-level
	>line-21 captioning (e.g., verbatim vs edited to a specific reading
level), with no way
	>to easily indicate what's in the data streams.  We could perhaps
solve that with
	>metadata that defines at least two types of data...

	>level: x, xx, xxx, etc., where x=editing level, reading speed,

	>...indicating to the user that two or three or four streams of data
exist.  Of course, this
	>opens up the problem of defining levels.  I'm not sure that's
appropriate for this
	>group.  But we could at least leave space for the options.  

Geoff, I think we are discussing the TT standard with largely different
perspectives, in that I am hoping for a standard that defines a mechanism
**just** for the transport of Unicode characters together with timing
information that controls when and for how long it is displayed.

From your comments it appears to me that you anticipate the standard to
define markup that categorises the information carried. 

I am hoping that the standard does not include semantics for the text being
transported - yet provides the option of carrying private or proprietary
tags for semantics if desired. Similarly I am hoping that the style of the
displayed text is defined by an optional mechanism (e.g. style sheets) and
that the end presentation of the text is primarily the responsibility of the
**viewer** implementation (and could be much different to the authors
conception). I am hoping that the TT standard is **unlike** SMIL,
RealPlayer, Quicktime. These existing standards IMHO already provide
competent solutions where the **authors** intended presenation of the
material is preserved totally through the transmission chain to the display

In some respects I see TT as more of an XML schema than as a new protocol or
format, but hesitate to support an XML representation as I am unsure how
certain aspects could be implemented. Further I think the single hierarchy
that XML enforces could overcomplicate a TT format.

regards 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 Wednesday, 5 February 2003 04:40:20 UTC

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