atsc, tv standards, & hdtv

ATSC, TV Standards, & HDTV

Bengliang Koh

Jon Nedel

18-899 Seminar

15 April 1998

Preview

• ATSC (Advanced Television Systems Committee)

• “A Tube for Tomorrow?”

• HDTV “Standards” & TV Networks

• Challenges for HDTV

ATSC History

• ATSC = Advanced Television Systems Committee

• Original charter: 11 May 1983

• Purpose: Explore the need for and coordinate voluntary national technical standards for Advanced Television Systems

• Systems included: generation, distribution, and reception of improved or enhanced TV, as well as HDTV

ATSC History (2)

• ATSC Membership– any business entity having a commercial

interest directly and materially affected by ATSC

– any non-profit organization whose members or activities are directly affected by the work of the ATSC

– government entities whose participation would be focused on technical standards

ATSC Members

• A sampling of ATSC Members:– International membership since May 1997

– TVABC

Canadian Broadcasting Corporation

CBS Broadcast Group

Televisa (Mexico)

– Communications

Bell Atlantic

DIRECTV

– Hardware/Manufacturers

Sun Microsystems, Inc.

Texas Instruments

Zenith Electronics Corporation

– Movie/Entertainment

Dolby Laboratories, Inc.

Eastman Kodak Company

Sony Advanced Systems Company

Universal Studios, Inc.

– Academic/Research

Industrial Technology Research Institute (Taiwan)

Institute of Electrical and Electronics Engineers

Massachusetts Institute of Technology

ATSC Activities

• Formation of ATSC subcommittees to draft ATSC Standards and Recommended Practices

• ATSC Standard – A document which states basic specifications or criteria which are

necessary for effective interconnection within advanced television

systems.

• ATSC Recommended Practice– A document which states specifications or criteria within advanced

television systems which are not necessary for effective interconnection, but which are thought to be advisable. An ATSC Recommended Practice may specify preferred methodology for implementation and operation.

ATSC Achievements

• Dec 1996 - FCC adopts ATSC standards for HDTV

• Adopts Dolby AC-3 (384kbps)– provides 5.1 channels (.1 = subwoofer)– cinema quality sound– dynamic range compression (for home viewing)– karaoke functions

ATSC Standard Documents

• A/52 = Digital Audio Compression (AC-3)

• A/53 (1995) = ATSC Digital TV Standard (HDTV)

• A/57 (1996) = Standard “Program/Episode/ Version Identification”– Means to uniquely define a program, episode,

version, and source within the MPEG-2 syntax– ID packet may vary to allow content ID

(programs, commercials, promotions)

ATSC Standard Documents (2)

• A/65 (1997) = Program and System Information Protocol for Terrestrial Broadcast and Cable– Caption Service Descriptor = type, language,

“easy reader”, wide aspect ratio– Content Advisory Descriptor = V-chip-like

rating identification system

“A Tube for Tomorrow?”

• Q: What’s so good about HDTV?– Visual detail, almost 3-D compared to analog, wide

screen, 5-channel sound

– Revenue for broadcasters, pay-per-view, paging, home shopping, Internet

– Uses same 6MHz (19Mbps) bandwidth used by standard TV

• Q: Why did FCC give away bandwidth?– Broadcasters have strong influence in Washington

– Start-up costs very dramatic for broadcasters

“A Tube for Tomorrow?” (2)

• Q: When and how much?– About 2 years from now over the air– About 2 years after that for Cable/DBS

• Q: Digital TV will turn my TV into a computer? Or vice versa?– Computers can receive HDTV signals– TV’s with input devices (keyboard, joystick,

mouse), i.e. “Interactive Television” (ITV)

“A Tube for Tomorrow?” (3)

• How long can I keep my analog set?– After 2006, FCC allows broadcasters to stop

delivering analog TV– Buy a new TV, or at least a converter box

• Will regular analog TV really disappear?– Did LP records disappear when CDs arrived?

• Will the shows themselves get better?– Dream on...

HDTV “Standards” & TV Networks

• CBS decided on “1080i” format, “the highest quality HDTV digital format.”

• ABC, NBC & FOX decided on “720P” format, “the right solution for a converged future.”

• 1080i = 1080 lines, interlaced format

• 720P = 720 lines, progressive format

• 480P = 480 lines, progressive format

Video StandardsR

esol

utio

n (l

ines

)

Frame rate (Hz)20 30 40 50 60 70

2500

2000

1500

1000

500 NTSC/PAL

HDTV

35mm Movie

WorkstationDisplays

70mm movie

SHD

Challenges for HDTV

• Video Coding

• Recording (Tape/Disk/DVD)

• Digital Photography/Image Capture

• Hardware Implementation (LSI)

• Conversion issues

• Satellite TV

Challenges for HDTV (2)

• Video Coding– Started off with analog MUSE (Multiple Sub-

Nyquist Sample Encoding)– Change from analog to digital brought about

move to MPEG-2 standard– With adoption of ATSC standards, not big

problem. FCC is adopting 18 formats (aspect ratio, frame rate, resolution, interlace etc.)

– Japan/Europe adopting DVB (MPEG-2 audio)


• Recording– Digital Disk Recorders (DDR)

• high speed hard disk drives

– Video Tape Recorders (VTR)• magnetic tape

• Sony DVCAM

• JVC Digital-S– 50 Mbps, 124 minutes

– 480/30p, four audio channels


• Recording (cont’d)– Sony’s DVD

• Uses MPEG-2 and AC-3

• SD-HDTV format

• 20+ GB

• more than 2 hours of recording


• Digital Photography/Image Capture– most 1080 line resolution content is created

from scanning existing 35mm film– need for very high resolution cameras– only studio cameras can achieve 1080 lines

• Hitachi SK-3000, 2,000,000 pixel CCD, 60Hz

– portable cameras give about 480 lines


• Hardware implementation (LSI)– video requires HUGE processing power – parallel architectures– MPEG-2 encoding requires about 15 GOPS– GHz processors available soon


• Conversion issues– upgrading costs

• television studios need to upgrade to digital editing equipment, transmitters, sets

• costs of $30-$60 million

– transition to digital• digital transmission on additional channel granted

by FCC while still transmitting analog signal


• Conversion issues (cont’d)– consumer markets

• need larger display to see increased resolution

• current receivers are pricey

• $3000 - $10,000

• PC cards ($1000-$2000) a cheaper interim option

• Interactive/multimedia content

– need to attract advertisers


• Satellite TV– DirecTV

• MPEG-2 digital SDTV

• 200 channels

• moderate success


• Satellite TV (cont’d)– PerfecTV, a Japanese commercial digital multichannel

statellite broadcasting corporation

• 27MHz (42Mbps) bandwidth, 13Mbps of which is dedicated to error correction code

• quality programming without commercial sponsors

• charging only for scrambled programs

• enabling pay per view (PPV) using a conditional access system without any reservation

• supplying an electronic program guide (EPG) with program selection functionality

• supporting e-mail service for users• exchanging data interactively through

a modem• preventing copying of PPV programs• multiplexing closed-caption data

A story about the power of HDTV

• About seven years ago, I had arranged for an HDTV demonstration for PBS Staff and PBS Station Managers. One of the people that I urged to attend was an attorney who was starting to work on FCC issues. She had never seen HDTV. We were fortunate to have a clip of a CBS made for TV movie that was shot in HDTV. The story was about children with AIDS. At one point in the clip, there is a close-up of a father watching his son in an emergency room. The ability of HDTV to convey human emotion is extremely powerful and my colleague began to cry. [Now certainly any time you can make a lawyer cry, it’s a good thing]. Seriously, I do think that this is the kind of viewing experience that HDTV can bring to the home. It is that vision of HDTV that inspires me.

– The Vision of HDTV, HDTV ‘96 Keynote Address, Mark S. Richer, Executive Director of ATSC

For more information...

• “Obtaining Higher Resolution in Asia”, IEEE Signal Processing Magazine, July 1997, Vol. 14, No. 4

• “A Tube for Tomorrow”, Time Magazine, April 14, 1997, Vol. 149, No. 15

• National Association of Broadcasters http://www.nab.org/conventions/nab98/index_lo.html

• http://www.contrib.andrew.cmu.edu/~bkoh/899/hdtv.html