Thread Subject: Re: thoughts from anotherdiscussion (related)

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From: Gregg Vanderheiden
Date: Mon, Feb 12 2007 9:10 PM
Subject: Re: thoughts from anotherdiscussion (related)

How about we require that the captions and description be provided in a
standard and supported fashion. Then have separate (sufficient) specifics
for different platforms.

Problem is the words 'standard' and 'supported'. How do we make the
testable. If we can figure that out it would allow this type of approach.


Gregg
-- ------------------------------
Gregg C Vanderheiden Ph.D.



> -----Original Message-----
> From: = EMAIL ADDRESS REMOVED =
> [mailto: = EMAIL ADDRESS REMOVED = ] On Behalf Of Sean Hayes
> Sent: Monday, February 12, 2007 4:32 AM
> To: TEITAC Audio/Video Subcommittee; TEITAC Web/Software Subcommittee
> Subject: Re: [teitac-video] [teitac-websoftware] thoughts
> from another discussion (related)
>
> I think what is needed here to navigate these difficult
> waters is to adequately document and legislate for user needs
> and to allow for equivalent facilitation in order to meet these needs.
>
> Support for specific technical standards like 608 and 708 is
> clearly not going to be possible uniformly across all
> devices, at least for many years. However the requirement
> that users have access to captioning (including display
> preferences etc), as well as other accessibility such as
> descriptive audio, spoken menu's, clear audio, signing etc.
> should be achievable, and that is what we need to document in 508.
>
> HD DVD and Blu-Ray are capable of any and all of the above,
> going well beyond the capabilities of 608 & 708 provided
> pressure is put on the content providers to include the data.
> It might also be possible with some effort to include such
> provisions for internet delivery in the future too.
>
> I think Larry's Plan B is probably the best route forward for
> digital TV and standard DVD, which is to decode 608 and 708
> as early as possible in the chain, and we should be able to
> come up with some technology neutral language in 508 to move
> in that direction.
>
> Sean Hayes
> Standards and Policy Team
> Accessible Technology Group
> Microsoft
> Phone:
> mob +44 7977 455002
> office +44 117 9719730
>
> -----Original Message-----
> From: = EMAIL ADDRESS REMOVED =
> [mailto: = EMAIL ADDRESS REMOVED = ] On Behalf Of
> Larry Goldberg
> Sent: 08 February 2007 14:33
> To: TEITAC AV list; TEITAC Web/Software Subcommittee
> Subject: Re: [teitac-video] [teitac-websoftware] thoughts
> from another discussion (related)
>
> One solution to the situation as described by Sean is to have
> the DVD players decode the caption data like set-top boxes
> do. That (STB decoding) was a solution imposed by the FCC and
> it works - though the user interface for set-top box
> captioning controls leaves much to be desired.
>
> In light of the fact that the US is not likely to, in fact
> cannot, drop 608/708, we need to live with these standards
> and support them in the way we can. There is a vast amount
> of equipment, regulations and investment in the
> 608/708 platforms and the effort by the 508 Refresh committee
> to take global harmonization of standards into account in its
> deliberations should not mean that any problematic, but
> embedded, US standard should be tossed aside in favor of
> yet-to-be-determined international approaches.
>
> I'd like to point all concerned to two pieces of information
> on this issue - one from the FCC and the other from the HDMI
> standards consortium. Both of the following statements
> clearly indicate that the solution lies in proper handling
> and decoding of 708 captions by all video source devices
> (including DVD players):
>
> Section 53 of the July 31, 2000 FCC Report and Order on DTV
> captioning stated the following:
>
> "53. Other Devices. Although we did not propose
> closed caption
> decoder requirements for television interface devices whose
> primary function is other than delivering television
> programming, such as VCRs, DVD players, or personal video
> recorders, we know that these devices are used by consumers
> in connection with their television sets to view closed
> caption programming. In order for viewers to receive closed
> captions when using these devices, it is not necessary for
> these devices to have decoding capability. Rather, all that
> is required is for the device to pass through the closed
> caption information to the decoder in the television set. We
> expect that such devices, and any other similar new devices,
> will pass through closed captions unaltered and intact to the
> decoder in the attached digital television. Manufacturers of
> such devices should ensure that this continues to be the case
> as the transition to digital television progresses."
>
> [Larry here again]:
> So the FCC justified not requiring video source devices to
> decode captions based on the assumption that they would pass
> through the data. Clearly BluRay and HD-DVD are not doing
> what the FCC expected, so there needs to be a Plan B. This
> paragraph implies that the Plan B would be for all video
> sources to decode caption data and pass the open captions to
> the display.
>
> Then we have the problem with the fact that the HDMI
> connector can't pass caption data anyway. When asked, here is
> what one of the chief authors of the HDMI spec had to say
> about this issue:
>
> > HDMI does not carry, nor need to carry, closed caption
> data. Nor does
> > component analog video. It's not needed because the source device
> > (STB, DVD
> > player) is required to "open" the captions. "Closed" captions are a
> > hidden stream of text characters that are not normally
> visible but are
> > carried with the video stream. "Open" captions are actually visible:
> > displayed on the screen.
> > So, the source needs to take the hidden text stream ("closed") and
> > draw those characters on the image data if the user turns on Closed
> > Caption. This happens upstream of HDMI so HDMI only needs
> to carry the
> > video signal, not the hidden closed caption data.
> > Another way of thinking of this is that it's the tuner that handles
> > closed captions. For normal TV signals, the tuner is inside
> the TV and
> > so it decodes and displays the data if the user selects it.
> For HDTV,
> > the tuner is in the set-top-box (STB) so it's the STB that
> does the decode.
> > The assumption of the
> > founders has been that the source device will decode and
> display the
> > captions and teletext.
>
> [back to Larry:]
> So clearly the authors of the HDMI spec thought the DVD
> players would decode captions - they even mistakenly believed
> that they were required to do so.
> Many of the members of the HDMI consortium are also members
> of CEA and were involved in developing the BluRay and HD-DVD
> specifications. And if a next generation DVD player happens
> to include a tuner, it would automatically be subject to FCC
> rules requiring it to decode 708 caption data.
>
> So, here we have a situation where the right hand didn't know
> what the left hand was doing - and deaf consumers and others
> who rely on closed captioning are faced with acceptance of
> either a lower quality image (composite video and last
> generation DVDs), an inflexible substitute (subtitles), and
> loss of an advanced technology (which allows user control)
> that they worked so hard to implement (the 708 caption specification).
>
> Let's continue this discussion.
>
> - Larry
>
>
>
> Sean Hayes wrote:
>
> > That's right, and for these reasons, as well as the fact that both
> > Blu-Ray and HD-DVD need to apply to a global market rather
> than just
> > to the US, closed captions in those formats are not encoded
> in CEA608
> > or 708, but (for HD DVD at least), either in DVD subtitles or as
> > subtitle applications. The devices can turn these on and
> off and the
> > TV acts as a pure monitor. Even if 608 was encoded in the
> video using
> > the same hack as was used for DVD, it could not be carried
> over any of the proscribed interconnects from the player to the TV.
> >
> > The same issue is going to be true for internet delivery of
> captioning
> > to TV's, it is not practical to convert to 608 or 708 on reception,
> > and even if carriage of these over IP was possible in internet
> > streaming formats, it would not be globally applicable
> requireing multiple encodings at the server.
> >
> > Unfortunately the captioning story around the world has siloed into
> > lots of different and incompatible formats, which is not to
> the benefit of the users.
> > The European Broadcasting Union has an activity underway to
> attempt to
> > address this, and the Timed Text DFXP format does offer the
> > possibility of a truly global captioning format,
> unfortunately it is
> > not likely to see widespread adoption in time for 508.
> >
> > The rest of the world is not going to adopt 608 or 708 for many
> > technical and political reasons, so the question for the US
> is whether
> > they would join an international effort to get to a single world
> > standard, and give up on 608/708 or to enforce these
> specific formats
> > as an extra tax on all imported equipment and lobby
> Hollywood and the
> > consumer electronics industry to change the HDMI standard.
> >
> > Sean Hayes
> > Standards and Policy Team
> > Accessible Technology Group
> > Microsoft
> > Phone:
> > mob +44 7977 455002
> > office +44 117 9719730
> >
> > -----Original Message-----
> > From: = EMAIL ADDRESS REMOVED =
> > [mailto: = EMAIL ADDRESS REMOVED = ] On Behalf Of Larry
> > Goldberg
> > Sent: 07 February 2007 19:15
> > To: TEITAC AV list; TEITAC Web/Software Subcommittee
> > Subject: Re: [teitac-video] [teitac-websoftware] thoughts
> from another
> > discussion (related)
> >
> > Not quite - the DVD players need to reconstitute the
> caption data that
> > was written onto the disks in the video user bits and
> encode it onto
> > line 21 for transmission to and decoding by the displays'
> caption decoding circuitry.
> > The original (1st gen) DVD players were not able to do this
> but later
> > models fixed that design flaw.
> >
> > Now we are facing the same situation with BluRay and HD-DVD - the
> > hardware cannot "sense" nor reconstitute caption data for
> transfer to
> > the HD display and the high-end connections make this
> impossible too.
> > So the DVD would need to decode the captions to make this
> work - like
> > cable set-top boxes and other HD receivers that are
> external to the display.
> >
> > - Larry
> >
> >
> > David Poehlman wrote:
> >
> >> Greg, DVD players have nothing to do with capttions, it's
> the dvds
> >> themselvs which have or do not have them. If they are
> available, dvd
> >> players will honor them if asked.
> >>
> >> On Feb 7, 2007, at 4:17 PM, Gregg Vanderheiden wrote:
> >>
> >>
> >>
> >>>> /This article states that most DVD players don't
> support closed
> >>
> >>>> captions.
> >>
> >>
> >>
> >>> Ugh.
> >>
> >>
> >>
> >>> On a similar note, I learned this morning that the strict
> definition
> >>> of
> >>
> >>> "podcast" doesn't allow video files to be captioned. From what I
> >>
> >>> understand, if a QuickTime file includes a text track
> (which is how
> >>> you
> >>
> >>> include captions for this format), then it can't be downloaded via
> >>
> >>> iTunes or played on an iPod...
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> Gregg
> >>
> >> ------------------------
> >>
> >> Gregg C Vanderheiden Ph.D.
> >> Professor - Depts of Ind. Engr. & BioMed Engr.
> >> Director - Trace R & D Center
> >> University of Wisconsin-Madison
> >> < <http://trace.wisc.edu/> http://trace.wisc.edu/> FAX 608/262-8848
> >>
> >> DSS Player at http://tinyurl.com/dho6b
> >>
> >> <http://trace.wisc.edu:8080/mailman/listinfo/>
> >>
> >>
> >>
> >>
> >>
> >>