HDTV Update

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(H)DTV Update
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• John M. Ashby
• Saint Louis University

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Convergence the migration of traditionally
analog technologies to digital processing,
storage, manipulation and transport.
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HDTV Consumer Interest and Visibility
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DTV in the News
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Why ATSC (Digital) Television ?
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• Computer-grade image technology
• No snow, ghosts, fuzzy pictures
• Dolby Digital Surround Sound
• Electronic Program Guides
• Multicasting, more possible channels
• Data services options

Mandated new US television standard WHEN to
convert, not IF!
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FCC Broadcast DTV Timeline
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NTSC (analog) vs ATSC (digital)
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• Interlaced video is used in ALL NTSC devices
• (VCRs, DVDs, TVs, Camcorders, etc.)
  progressive scan means converted as in
  computer display.

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NTSC (analog) vs ATSC (digital)
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• Resolutions, frame rates, aspect ratio
• High Definition, Enhanced Definition, Standard

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Technology Computers?
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Be careful of your assumptions and definitions-
digital technology need not mean PCs (or Macs or
Linux)!
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The Digital Television Migration Puzzle
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Receive
Display
New Questions
Transmit
Record/Play
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Receiving the DTV Signal(Coax 75 Ohm into
receiving device)
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8 VSB (Off-air broadcast)
QPSK (Satellite broadcast)
QAM (Cable TV broadcast)
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ATSC Receivers
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• External ATSC (8VSB) set-top boxes were the only
  receiving option, until recently
• Display-integrated ATSC off-air tuners are now
  emerging
• Satellite DTV (QPSK) may have off-air tuner, but
  licensed per set or drop
• Unencrypted cable (QAM) support hard to find in
  retail receivers, but emerging (LG, others)-
  important for higher ed market!

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Cable DTV Receivers
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• Cable DTV (QAM) originally was conceived as a way
  to sell more standard channels on existing
  bandwidth now responding to HD pressures
• Receivers are typically addressable,
  bi-directional devices provided by cable company-
  Video-on-demand, interactive applications
  possible.
• CableCard slot becoming standard for digital
  cable ready displays without set-top box.

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Antennas for Off-air
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• Indoor or outdoor placement and interference
  may be as important as sensitivity
• Optimized to reduce multipath interference

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Antenna Selection and Aiming
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• http//www.checkhd.com/ for coordinates, antenna
  needs, and signal strength of local stations
• Community antenna refeeds for higher ed no
  per drop licensing
• CATV infrastructure can be expanded for DTV
  origination

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DTV Display Types
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• CRT televisions, displays (analog scan beam)
• Projection and Rear-projection pixel-mapped
  displays (LCD, DLP)
• Plasma, LCD flat panel pixel-mapped displays
• Emerging pixel-mapped technologies LCOS, OLED,
  NED, FED, SED

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Display Resolutions
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• HDTV modes are 169 aspect ratio
• Standard definition (SD) is 43 aspect ratio,
  like computer and video.
• Frame rate in DTV video equivalent to refresh
  rate in computer display terms.
• Consumer market term EDTV 480p native resolution

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Display Comparison
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Pixel Counts vs. Signal Resolution
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• Pixel mapping (compression is common term-
  dropping pixels selectively in preprogrammed
  patterns)
• Scaling and other intelligent processing
  algorithms (e.g., LG Electronics XD Engine)
• Analog always requires processing from a digital
  signal (even NTSC video out).

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DTV Origination One Step at a Time
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Transitioning Content to DTV
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• Heterodyne processor off-air tuning and
  retransmit to cable channel as 8VSB (Drake,
  Harris)
• Tune 8VSB or QPSK, retransmit to cable as QAM
• Be sure your HDTV receivers can tune mixed
  analog, 8VSB, QAM

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Other DTV Content Options(Currently complex and
expensive)
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• Encode NTSC as SDTV (e.g. Adtec Edje 2100
  encoder)
• MPEG-2 Video Server (varied costs)
• Realtime DTV encoding from pro HD production
  equipment
• Above create MPEG-2 transport stream for QAM
  modulator (e.g. Drake)

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Other DTV Transmission Issues
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• Multiplexer can encode up to four SD channels
  onto 1 CATV channel
• DVB-ASI interface is new standard for source
  outputs to Multiplexer or QAM
• IP transport options for long-haul or
  high-performance circuits (e.g. VBrick)
• Above create MPEG-2 transport stream for QAM
  modulator (e.g. Drake)

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DTV Tape Options
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• Professional DV formats
• DVHS
• DV tape, proprietary format (e.g., JVC GR-HD1)

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DTV Record/playback
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• HD-DVR
• Computer capture
• Format Wars! Blu-Ray vs. HD-DVD

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Transitional Technology Challenges
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• New compression algorithms evolving MPEG-4,
  H.264 AVC, VC-1 WM9
• New interfaces between equipment (HDMI w/audio
  vs. DVI) and more to come (VESA DisplayPort)
• Analog interfaces have not disappeared (RGB, Y Pb
  Pr, Composite, S-video)
• Analog RGB interfaces may be blocked by copy
  protection
• New digital audio interfaces (SPIDIF, Coax)

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Intellectual Property Challenges
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• The Broadcast Flag and the FCC
• High Bandwidth Digital Copy Protection (HDCP)
  built into digital interfaces
• DRM over IP, new copy protection technologies
• Movie studios want to re-sell content to
  returning customers in new formats, but fear
  piracy.

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Digital Television Penetration 2005
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• Decisionmark Corp. reports that 95 of US
  households are now covered by one or more
  network DTV signals, compared to 97.6 for
  analog.
• 74 can receive 4 networks.

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Links
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• http//www.samsungusa.com/dtvguide (good consumer
  overview)
• http//www.highdefforum.com/terms.html (informal
  language HDTV glossary)
• http//myfreehdtv.org/ (links to programmers,
  antennas, product advice)
• http//www.hdtvexpert.com/ (Peter Putman general
  tech discussion forum)
• http//www.16nine.com/ (News info)
• http//www.eff.org/IP/Video/HDTV/ALA_v_FCC/
  Electronic Frontier Foundn.
• http//www.mpaa.org/Press/Broadcast_Flag_QA.htm
  MPAA point of view
• http//www.rldrake.com/digital/ATSC-off-air.pdf
  (midrange CATV products)
• http//www.adtecinc.com/ (encoding and DTV
  products)
• http//www.xilinx.com/esp/ (Digital video
  engineering concepts)

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John M. AshbyDirector, Educational
TechnologyInformation Technology ServicesSaint
Louis University
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• Phone [phone]
• Fax [phone]
• Email ashbyjm_at_slu.edu