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text-format discussion from today's call

From: Geoff Freed <geoff_freed@wgbh.org>
Date: Thu, 5 Aug 2010 12:52:01 -0400
To: HTML Accessibility Task Force <public-html-a11y@w3.org>
CC: Judy Brewer <jbrewer@w3.org>
Message-ID: <C8806471.F709%geoff_freed@wgbh.org>

Greetings, all:

Regarding the conversation on the call today about timed-text formats, I'd like to offer some further thoughts regarding the format eventually recommended by the a11y group and/or HTML5 and how it may affect others.  At a minimum these comments may further complicate matters.  Sorry...

Some on the list may be aware that SMPTE (Society of Motion Picture and Television Engineers) is coming close to completing a standard for the repurposing of broadcast captions for IP delivery.  This standard, called SMPTE-TT, is based almost entirely on TTML.  SMPTE-TT will provide broadcasters a clearly defined method for converting huge libraries of existing captions for Web delivery.

Many here may also be aware of legislation making its way through the U.S. Congress that will, in some form, mandate the inclusion of captions and descriptions on some types of video material on the Web, most likely related to material that originates in the broadcast sphere and is then transferred to the Web.  The U.S. House of Representatives passed its version of the bill (HR3101, The 21st-Century Communications and Video Accessibility Act; http://www.coataccess.org/node/9733) last week, and the Senate is still debating its version but is expected to complete its work soon.

Among its many provisions, HR3101 contains the following language:

(1) CLOSED-CAPTIONING REPORT.-Within 6 months after the date of the first meeting of the Advisory Committee, the Advisory Committee shall develop and submit to the Commission a report that includes the following:

(A) An identification of the performance objectives for protocols, technical capabilities, and technical procedures needed to
permit content providers, content distributors, Internet service providers, software developers, and device manufacturers to
reliably encode, transport, receive, and render closed captions of video programming delivered using Internet protocol.

(B) An identification of additional protocols, technical capabilities, and technical procedures beyond those available as of the
 date of enactment of this Act for the delivery of closed captions of video programming delivered using Internet protocol that
are necessary to meet the performance objectives identified under subparagraph (A).

(C) A recommendation for any regulations that may be necessary to ensure compatibility between video programming
delivered using Internet protocol and devices capable of receiving and displaying such programming in order to facilitate
access to closed captions.

C is most relevant here:  it's stating that the committee must recommend a format for IP delivery of captions.  The committee specified in (1) will probably have significant representation from the broadcast world, and my educated guess is that broadcasters are probably going to push for SMPTE-TT as the standard to specify in the regulations.  If there is a disconnect between this recommendation and what is recommended in HTML5, it could create a significant headache for the broadcast industry.  In short, harmonization of the text-display formats would be ideal.

It's important to keep this specific issue in mind while debating the text-format problem, and I raise it just to remind everyone that a good deal of video on the Web, especially captioned video, originates elsewhere and will continue to do so for some time.  The amount of captioned programming repurposed from the broadcast world is significant, and we should be paying close attention to what is happening there.  Broadcasters will probably favor a single conversion format for captions from terrestrial/cable to Web.  In other words, if they're already having to convert from CEA-608/708 to SMPTE-TT (not a done deal), they're probably not going to want to do another conversion, with potentially different results or limitations, to whatever format is recommended by HTML5 and its implementers.


Received on Thursday, 5 August 2010 16:54:28 UTC

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