Deborah D. McAdams / 02.17.2011 12:00AM
Video Description Rules are Kind of at Hand
RANCHO MIRAGE, CALIF.: Regulations requiring
broadcasters to provide verbal descriptions of program images will be
reinstated in October. Best get in front of it, said Art Allison of the
National Association of Broadcasters at the HPA Tech Retreat this week in
the California desert. Video description rules call for the “insertion of
audio-narrated description of a TV program’s key visual elements into natural
pauses between the program’s dialog.” The service is intended to make
programming more assessable to the blind.
Video description rules were approved by the FCC in 2000 and struck down in
court two years later. They were reinstated last year in the “Twenty-First Century Communications and Video
Accessibility Act of 2010,” though limited to the big four network affiliates in the top 25 markets plus the top five
national cable networks. The networks will have to provide 50 hours per quarter
of programming with video description service, excepting live and near-live
programming. The rules are to be implemented over a phase-in period and extensions
will be considered for stations and providers lacking the requisite technical
capability. Consequently the ultimate deadline could be out a ways.
“It’s not tomorrow, but it is coming,” Allison said, describing the
configuration for provision of VI (for “visually impaired”) with 5.1 surround
sound. E.g., a single stereo VI can ride the 5.1 signal in two of the eight
channels in a Dolby E stream. Two Dolby E streams with 16 channels can
carry two 5.1 signals, each with an associated stereo audio VI mix, or a single
5.1 service and five stereo audio streams.
The FCC regulation doesn’t state what language the video description needs to
be in, so technically, it could be Spanish. With regard to transmission,
several audio services can be sent with a single video channel, but the PSIP
virtual channel guide may get crowded. (PSIP or Program and System Information
Protocol, carries the information that tells TV sets what’s in a TV signal.)
Using separate virtual channels for say, English and Spanish in the main
channels, the VI feeds and for hearing-impaired feeds adds six choices in
guide.
The Consumer Electronic Association is working on a standard, CEA-CEB-21,
Recommended Practice for Selection and Presentation of DTV Audio. It provides
guidance to receiver manufacturers on how to parse an ATSC audio stream so
viewers can find what they want without an engineering degree. Work commenced
on the standard in mid-July; the second pre-vote comment round came to a close
Nov. 22, 2010. Allison said it’s nearly done.
He earlier expressed frustration with the consumer electronics industry for not
supporting dual-stream Dolby Digital, or AC-3, coding. The original ATSC
standard for the transmission of digital broadcast television allowed for
dual-stream AC-3, which would have supported multiple audio streams. However,
it was not made mandatory and receiver makers therefore did not incorporate it
into TV sets. Dual-stream AC-3 would have been more bandwidth efficient than
the configurations with Dolby E.
“Receiver makers refused to support the original Dolby design to save bits by
enabling supplemental audio tracks, so service providers must consume bits to
send everything for any audio service,” he said. Then making a winking
reference to Gary Shapiro’s best-seller, “The Comeback,” which makes the case
for reclaiming TV spectrum for broadband, Allison added, “I wonder if that is
in Gary’s book.”
-- Deborah D. McAdams