Taiwan DTV Committee 社團法人台灣數位電視協會石佳相博士台灣數位電視協會常務理事華電聯網新媒體應用整合處副總經理 2009.04.17 高畫質電視面面觀

Taiwan DTV Committee

社團法人台灣數位電視協會

石佳相博士石佳相博士台灣數位電視協會常務理事台灣數位電視協會常務理事

華電聯網新媒體應用整合處副總經理華電聯網新媒體應用整合處副總經理

2009.04.172009.04.17

高畫質電視面面觀高畫質電視面面觀– – HDTV Overview – HDTV Overview –

高畫質電視面面觀高畫質電視面面觀– – HDTV Overview – HDTV Overview –

98 年度高畫質電視的未來與發展國家通訊傳播委員會專業技術講習課程

98 年度高畫質電視的未來與發展國家通訊傳播委員會專業技術講習課程



Dr. C. Stone Shih is Vice President of New Media Division, HwaCom Systems Inc. His work experience and expertise concentrates on digital broadcasting technology, multimedia platform technology, as well as digital set-top-box design and system integration. To help promoting digital TV developments in Taiwan, Dr. Shih also serves as important leaders in various industrial organizations and provides consultancy services to government offices.

Prior to HwaCom, Dr. Shih was CEO and co-founder of DAWN TV Technology Corporation as well as Vice President of Communication Department, CMC Magnetics Corporation. Before Joining CMC, Dr. Shih co-initiated a DVB-S based DTH service platform Pacific Digital Media (PDM) in Taiwan (PDM became TV-Plus later). Dr. Shih was CTO of the PDM operations which he was responsible for the technical aspects of the PDM DTH platform developments. The PDM DTH business plan was drafted while Dr. Shih was Vice President of TV Time Entertainment Networks (TVTime), a cable channel provider in Taiwan. Prior to TVTime, Dr. Shih was with a digital set-top-box vendor Visionetics in Science-Based Industrial Park, Hsinchu, Taiwan. While with Visionetics, Dr. Shih led a team finishing a DVB Set-Top-Box development project which was partially funded by the Industrial Development Bureau, Ministry of Economic Affairs, R.O.C. (IDB/MoEA).

Earlier in the US, Dr. Shih worked on a video server project in a VOD trial while he was with IBM T.J. Watson Research Lab. at Yorktown Heights, NY. After IBM, Dr. Shih co-initiated a satellite based cable content provision company Entertainment Research and Applications (ERA) in Los Angeles.

Dr. Shih received his Ph.D. and M.S. in Computer System Engineering from University of Massachusetts and his B.S. in Electrical Engineering from National Taiwan University.

Dr. Shih is participating and is a member of: IEEE Computer Society, Communications Society, and

Broadcast Technology Society Digital Video Broadcasting (DVB, a DTV Launching Project of

EBU / ITU) Broadcast Mobile Convergence Forum (bmcoforum, an

international organization for Mobile Broadcast Services) Audio and Video Coding Standard Workgroup of China (AVS

Workgroup of China)

Digital Video Industry Development Program Office, IDB/Mo

EA (Senior Consultant) Taiwan DTV Industry Alliance (Co-Chair, Representative of In

dustry, of the DTV Standards Working Group) Taiwan DTV Committee (Director General, Board Member) Taiwan Digital Video Association (Board Member) Taiwan Mobile TV Industry Forum (Vice Chairman)

2009/04/17 - 2 -HDTV Overview



Focuses

電視發展史與高畫質電視的演進高畫質電視的相關技術與標準高畫質電視的產品與應用

- 3 -2009/04/17 HDTV Overview



Outlines

History of TV The search for TV Standards Technical Aspects Products and Implementations FCC Standard Setting in HDTV The HDTV spectrum allocation at the FCC Concluding Remarks




Outlines





History of TV

1842 Alexander Bain managed to transmit a still image over wire. First fax machine!

In 1884 Paul Gottlieb Nipkow went a step further, and discovered (and patented) a way to scan a moving image and transmit it sequentially. Birth of mechanical television!



社團法人台灣數位電視協會Mechanical Television



社團法人台灣數位電視協會Mechanical Television

John Logie Baird, a Scottish inventor, demonstrated what many refer to as the first television broadcast on January 26, 1926. Baird’s grayscale image, presented to members of the Royal Institution in London had only about 30 lines of resolution.



社團法人台灣數位電視協會First “mass produced” TV set




Mechanical Television

1927 - First TV broadcast in the US Herbert Hoover From NY to Washington Had about 50 scanning lines Broadcast by wire and radio




Electronic Television

1934 Philo Farnsworth demonstrated an all-electronic system

Less cumbersome than mechanical TV

Quickly gained popularity




Outlines





The search for standards: the FCC & the NTSC

FCC Established by the Communications Act of 1934.

Radio Manufacturers Association (RMA) recommended a standard for television using 441 horizontal scan lines and 30 frames per second with a 4:3 aspect ratio.





FCC urged the RMA to form the National Television System Committee (NTSC) in 1940.

1941 - NTSC established its first set of standards, which kept the 4:3 aspect ratio but called for a higher resolution image with 525 scan lines refreshing at a rate of 30 interlaced frames, or 60 fields per second. (263 lines followed by 262).





FCC allotted 6 MHz slices of bandwidth to TV stations.

Eventually covered a frequency range spanning from 54 MHz to 890 MHz on the broadcast spectrum.





1950s brought the addition of color (Home viewing was brought a step closer to cinema). CBS Color System failed due to compatibility issues

1953 - The NTSC standard had to be revised to adapt to color TV.

Engineers split the signal into two components: luma, which contained the brightness information, and chrominance, which contained the color information.

Field refresh rate of 60 Hz was slowed down by a factor of 1000/1001 to 59.94 Hz.

Broadcast television downshifted from 30 to 29.97 frames per second.




Same old standard

Many improvements were made in cameras, production and broadcast gear, and in television receivers.

Despite advances, the quality of analog broadcast was still limited to the NTSC standard of 60 fields and 525 horizontal scan lines.

Stuck with more or less same standards created in 1941. By the 1980s, manufacturers had been developing and

using both analog and digital HD systems. It became clear that the replacement for analog would use

digital television technology. Needed a new set of standards to ensure compatibility.




ATSC

Formed in 1982 The Advanced Television Systems Committee is

a not-for-profit organization whose purpose is to develop standards for the transition to DTV.

Its published broadcast standards are voluntary unless adopted and mandated by the FCC.

ATSC proposed DTV Standard (A/53) that specifies the protocol for high-definition broadcasting through a standard 6MHz channel.




DTV Switchover

In December 1996, the FCC adopted standards proposed by the ATSC, mandating that broadcasters begin broadcasting digitally.

WRAL of Raleigh, North Carolina was the first station to broadcast in digital.

FCC’s current plan is to terminate analog broadcasting by June 2009.




DTV, SDTV, & HDTV

NTSC standards defined one analog format ATSC created a framework supporting multiple

digital formats There is considerable confusion among

consumers regarding SDTV, DTV and HDTV. Broadcaster do not have to broadcast in HD, just

in DTV.



社團法人台灣數位電視協會DTV Formats

- 21 -2009/04/17

HDTV/SDTV

Horizontal lines

Vertical lines

Aspect Ratio

Frame Rate

SDTV 640 480 4:360p, 60i, 30p, 24p

SDTV 704 4804:3 and

16:960p, 60i, 30p, 24p

HDTV 1280 720 16:9 60p, 30p, 24p

HDTV 1920 1080 16:9 60i, 30p, 24p

Note: Non-integer formats (eg. 29.97) omitted for clarity.

HDTV Overview


社團法人台灣數位電視協會HDTV & SDTV Comparison

SDSD HDHD

704/720 pixels per line

480/576 Active lines

( from 200 000 to 400 000 pixels)

1280 or 1920 pixels per line

720 or 1080 active lines

( from 900 000 to 2 000 000 pixels)

Image

Definition

Image

Definition

AudioAudio Mono or Stereo Sound 5.1

Digital Dolby6 tracks

Increasing picture resolution and sound quality




HD Video Formats

HDTV Overview - 23 -2009/04/17

10801080

1920192000

2,073,6002,073,600

11521152

14401440

1,658,8801,658,880

720720

12801280

921,600921,600576576

720720

414,720414,720480480

345,600345,600

1,552,2001,552,200



Standard Definition Television SDTV

The current television display system 4:3 aspect ratio picture, interlace scan Australia/Europe

625 lines - 720 pixels x 576 lines displayed 50 fields/sec 25 picture frames/sec 414720 pixels total

USA/Japan 525 lines - 704 pixels x 480 lines displayed 60 fields/sec 30 picture frames/sec 337920 pixels total




Enhanced Definition TV Sets (EDTV)

Enhancements on TV sets Intermediate step to HDTV Doubled scan rate - reduce flicker Double lines on picture - calculated Image processing - ghost cancelling Wider aspect ratio - 16:9 Multi-channel sound




High Definition Television - HDTV

Not exactly defined - number of systems System with a higher picture resolution Greater than 1000 lines resolution Picture with less artefacts or distortions Bigger picture to give a viewing experience Wider aspect ratio to use peripheral vision Progressive instead of interlaced pictures




HDTV – Have We Heard This Before?

The very first TV system had just 32 lines When the 405 line system was introduced

it was called HDTV! When 525/625 line black & white came along

it was called HDTV! When the NTSC/PAL colour system was introduced

it was called HDTV by some people. Many of the enhanced TV (EDTV) sets introduced

they were labelled as HDTV. Now we have 1000+ line systems and digital

television - guess what? Its called HDTV!




Outlines





Standards and formats

Vision 1250

MUSE ATSCSMPTE 260

SMPTE 274 M

1998

SMPTE 295 M

1998

ITU-R BT 709-5

2002

SMPTE 296 M

1920x1080

1240x720

I ? P

?PSF

?24

,25,

30,5

0,60

A jungle of standards and formats



社團法人台灣數位電視協會 Technical Aspects

SMPTE 274 M SMPTE 296 M ITU-R BT.709-5

Number of active pixels

per line

Number of active lines

per frame

Picture aspect ratio

Scanning mode

Frame rate

Formats are described by:

Current main standards are:




SMPTE 274 M

11 formats at 1920 X 1080,

8 progressive , 3 interleaved

11 formats at 1920 X 1080,

8 progressive , 3 interleaved




SMPTE 296 M

8 formats at 1280 x 720, all progressive8 formats at 1280 x 720, all progressive

And a war of standards…




And then ITU-R BT.709-5…

This standard unifies the different American, European and Japanese HD systems, and establishes a bridge with digital cinema. It recommends:

–A unique Common Image Format 1920 x 1080.–A common data bit rate 1,485 Gigabits/.s– Allowing all the picture rates of interleaved and progressive television and cinema picture rates: – ( 50i,60i,25p,25 psf,30p,30 psf,50p and 60 p) and(24 p and 24 psf)




The Codecs

Codec is short for compressor-decompressor or coder-decoder, and refers to a manner in which data is compressed and uncompressed.

Broadcast and production codecs differ. In order to squeeze the data into a form that can

be reliably broadcast within a 6 MHz section of bandwidth, the HDTV signal must be compressed at about a 50:1 ratio.




The Compression Codecs

Most DTV broadcasts (terrestrial, cable & satellite) use MPEG-2.

MPEG-2’s compresses the video into groups of pictures (GOPs) not individual frames. Images are divided into macroblocks, which are areas of 16 x 16 pixels.

GOPs are created with three types of pictures: I, P, and B frames. I frames are intracoded frames. P are predicted frames and B are bidirectional frames.




Data services

In addition to audio & video, DTV contains metadata - auxiliary information related to the program or its content including audio dialog level info, closed captioning, format descriptor tags, and digital rights management (DRM) data.




Scanning modes

- 37 -2009/04/17

Interlaced display

HDTV Overview

HDTV allows for both interlaced and progressive content. Progressive mode is preferred by the HDTV.



Scanning mode comparison

HDTV Overview 38

-source Image

1st field

interlacedscanning(2 passes)

2nd field

progressive scanning(1 pass)

Segment B Segment A

Segmented frames

Flicker and

feathering

No flicker,no

feathering

No flicker or feathering and

easier compatibility with interlaced

mode

Interlaced, Progressive, Progressive Segmented Frames

2009/04/17



Flickering effects of Interlaced mode

Flicker is visible fading between cycles displayed on video displays, especially the refresh interval on cathode ray tube (CRT) based screens.

Flicker occurs on CRTs when they are driven at a low refresh rate, allowing the screen's phosphors to lose their excitation (afterglow) between sweeps of the electron gun.

For example, if a CRT computer monitor's vertical refresh rate is set to 60 Hz, most monitors will produce a visible "flickering" effect, unless they use phosphor with long afterglow. Most people find that refresh rates of 70-90 Hz and above enable flicker-free viewing on CRTs. Use of refresh rates above 120 Hz is uncommon, as they provide little noticeable flicker reduction and limit available resolution.

A similar effect occurs in PDPs during their refresh cycles. Since the shutters used in LCD for each pixel stay at a steady

opacity, they do not flicker, even when the image is refreshed. The backlights of such displays do flicker, but typically operate in the range of 150-250 Hz.




Feathering effects of Interlaced mode

Progressive Interlaced




Frame rates

DTV supports multiple frame rates including 24p, 25p, 30p, 50p, 60p, etc.

24p is the standard film frame rate used by the motion picture industry for years.

Allows for easier transfer to / from film.




Aspect ratios

16 x 9 aspect ratio more closely matches widescreen film formats.

DTV supports the display of traditional, standard resolution, 4:3 content.



社團法人台灣數位電視協會Aspect ratios




Conversion

Up-converting (converting to a superior format) Down-converting (converting to a lesser format) Scaling / sizing Aspect ratio manipulation / conversion Common to see broadcasters delivering images

with the improper aspect ratio.




Up Conversion -- SD to HD conversion

The main functions that an up converter must achieve, are: Calculation of missing pixels and lines Frame rate conversion Resizing De-interlacing

Quality of the output depends mainly on the de-interlacing process which is the most difficult to achieve.




Aspect ratio manipulation and resizing (SD -> HD)

4:3

4:3

16:9

Zoom + Top/ Bottom Crop

16:9

Side Panel




4:3

4/3

16:9

Stretching

16/9

left + right Stretching

Aspect ratio manipulation and resizing (SD -> HD)




Up Conversion -- Quality issues

It is clear that up conversion : Emphasises noise Introduces impairments:

in the transients, in fast moving pictures and in low light pictures ( Stairs effects, blocks, and

shifts).

Improved processes must be required to reduce these artefacts as much as possible




Frame rate conversion - 3-2 pulldown

- 49 -2009/04/17

Used to convert film or 24p to interlaced 29.97

HDTV Overview



Outlines





Products and Implementations

HDTV production typically begins with a high-definition camera, or a project shot on film then converted to a digital format.

Other means are possible. Much of Tim Burton’s recent stop-motion feature, The Corpse Bride was shot with a Canon digital still camera, and then transferred to digital video for editing.

Many commercials, cartoons, and full-length features have been created solely with animation software.




HDTV Cameras

HDTV cameras have been used for private applications long before the ATSC standards were in place.

Higher-end production cameras suitable for studio or digital cinematography can cost well over $100,000. (That’s not including the lens!)

Sub-$1,000 range targeted to consumers are pushing sales on the lower end.




Recording and Playback

Recording & playback can be done in many ways: Tape Hard-drive Optical disc RAM





D-VHS – This consumer format from JVC records onto VHS tapes using an MPEG-2 stream at up to a 28.2 Mbps data rate.

HDV – Canon, Sony and JVC offer relatively lower cost cameras that record at a maximum resolution of 1440 x 1080. HDV uses a form of MPEG-2 compression that results in a 25 Mbps signal that can be recorded onto miniDV cassettes.

DVCPRO HD – Also known as D12, DVCPRO HD was developed by Panasonic and has versions that record on magnetic tape as well as memory cards.





XDCAM HD - Sony’s tapeless format records onto Blu-Ray optical discs using several possible codecs. It can record HD content using MPEG-2 encoding at up to 35 Mbps or DV25 for DVCAM, and MPEG-4.

D-5 HD – Developed by Panasonic in 1991, the D-5 format has been updated to HD. Handles 720 and 1080 content at most possible frame rates.

HDCAM - Sony’s format records onto 1/2” videocassettes at a number of possible frame rates. It uses a 593 Mbps data rate and supports up to 8 channels of audio.

HDCAM SR - data rates up to 8800 Mbps with up to 12 audio channels.




Editing

MPEG-2 works well for transmission, but is not an ideal choice for editing due to its GOP structure and high compression ratio.

Editors typically want access to discreet frames with less compression.

In addition to the standard bit depths of 8 and 10, there are also higher end, 16-bit codecs available from companies like Pinnacle and Digital Anarchy.




Editing Storage

HD content, especially uncompressed, takes massive amounts of bandwidth and disk space.

Consider this comparison: An hour of DV footage with a stereo pair of 16-bit

audio tracks takes approximately 14 GB of disk space.

An hour of 10-bit 1920 x 1080 HD footage with a pair of 24-bit audio channels requires nearly 600 GB of space.




Display Technologies

CRT - CRT monitors draw the lines one after the next, from top to bottom to make an entire frame. Generally speaking they have pleasing color balance performance and wide viewing angles. Because of their use of vacuum tubes, the displays can’t be constructed much larger than 40” or so.

Plasma – Plasma HDTV sets are thin and are made up of cells that correspond to pixels sandwiched between glass plates. Plasma cells contain three separate gas-fill sub-cells, one for each color. When a current is applied to a sub-cell, it ionizes the gas emitting ultraviolet light. The ultraviolet light in turn excites fluorescent substances in the sub-cells that emit red, blue or green light.





LCD – LCD HDTV monitors work by casting light through an array of cells sandwiched between two polarized planes. LCD monitors are less expensive than CRTs to manufacture and come in both flat panel and rear projection varieties. Flat panel, direct-view monitors have become popular as computer and DTV monitors as they are bright, use less electricity than CRTs, and have a relatively long life span.

DLP – Digital light processing is a technology used in

projection displays. In DLP monitors, light is reflected off an array of microscopic hinged mirrors. Each tiny mirror corresponds to a visible pixel. The light is channeled through a lens onto the surface of the screen. Single chip DLP projectors can display 16.7 million colors. 3-chip projectors can display 35 trillion colors.





LCoS – Similar to DLP, LCoS projection systems use liquid crystals instead of mirrors to block light. The liquid crystals are arranged in a grid in front of a highly reflective surface.




Outlines





Old Technology towards New Technology

When a new technology is invented, there are a few interesting questions. The effects of compatibility between two different

generation of technologies on firms and customers?


Old Hardware

Old Software

New Hardware

New Software

Forward compatibleBackward compatible

Old Technology vs. New Technology



The Compatibility issues Non-compatible: Nintendo

Backward compatible: CD/DVD, Sony PS/PS2, MS DOS/Window O/S, BW/Color TV

Forward compatible: BW/Color TV, Color/HDTV

For increasing the adoption of color TV, which one is better?

(1) B/W can receive color TV signal.

(2) B/W cannot receive color TV signal.




The Story of FCC Color TV decision

The color TV technology used in the US today is known as the National Television Systems Committee (NTSC) system.

In 1941, RCA, the owner of NBC and a leading manufacturer of black-and-white sets, was a powerful force in the radio and television world.

Throughout the 1940s, CBS, the leading TV network, was pushing for the adoption of the mechanical color TV system it was developing.




The Story of FCC Color TV decision

The FCC adopted the CBS system in Oct 1950 A major obstacle for the CBS system was that it was not

backward-compatible: B/W sets would not be able to receive color program.

CBS had no manufacturing capability and no alliances with manufacturers.

Since a major consumers with B/W TVs could not receive color TV signals, limited programs in color were available.

To customers, color sets offer little added value because of the limited programs in color.

In 1953, the FCC officially reversed its 1950 decision so that B/W TV sets could receive color TV signals.

Then, the number of programs in color increases.

Forward compatibility increased the color TV adoption.




Lessons learnt from FCC Color TV decision

TV system has three major components: programming, distribution equipment and reception equipment.

The effects of compatibility, a direct effect and an indirect effect.

For HDTV to succeed, HDTV programming must be available, HDTV signals must be delivered to home, and consumers must purchase HDTV receivers and videotape machines.




HDTV Development in the U.S. To broadcasters as a group HDTV was a threat, not a promise

HDTV increase their costs considerably, e.g. transmission equipment costs $38m

They cannot charge more for an improved service They only benefit if viewers watched more TV. They probably would but not by

much because on average each TV household already watches seven hours a day.

Each individually might want to adopt HDTV, but as a group all might be worse off

A prisoners’ dilemma structure among broadcasters In broadcasting, they could do that to prevent HDTV’s adoption:

They discourage FCC from moving quickly to set standards for HDTV The claim that the already developed technology was unsuitable and delay any

implementation Broadcasting has traditionally been organized around local stations

These terrestrial broadcasters face increasing competition Cable TV Direct broadcast satellites - signals sent to home satellite dishes Fiber optic networks to homes




Outlines





The challenges of the HDTV spectrum allocation

Competition for spectrum at the FCC FCC considered reallocating some unused parts of

TV’s ultrahigh frequency band (UHF) to cellular service

Scarce Spectrum Allocating Criteria Scarce Spectrum should be reserved for applications

that are highly valued; and cannot easily be offered without using such spectrum




Challenges toward Terrestrial HDTV

A heavily squeezed HDTV system Extra costs Compromised quality Reduced scope for later enhancements

Less spectrum available for other uses Even less spectrum for other uses when

additional spectrum was allocated to existing terrestrial broadcasters to reduce interference between adjacent channels

Major social cost of implementing HDTV through terrestrial broadcast is the use of scarce spectrum space




Challenges toward Terrestrial HDTV

HDTV signals can easily be sent via cable or via satellite signals that do not use the crowded and valuable portion of spectrum suitable for ground-to-ground transmissions.

A new generation of DTV presents an opportunity to reconfigure use of the spectrum Provide TV service via satellite or via cable Can free up critical spectrum space for a number of

alternative technologies for future use But

FCC decided to fit HDTV into the already crowded terrestrial TV spectrum




Also decided by the FCC…

FCC decided to protect the installed base in the hands of consumers as well as to protect the existing broadcast industry

It decided that the introduction of HDTV must not strand owners of existing sets

Either the HDTV standard must be receiver compatible or else NTSC broadcasts must be “simulcast” alongside HDTV broadcasts during a probably long transition period

FCC has decided to use a simulcast approach




Outlines





Usage/Saturation

A recent survey carried out by Panasonic in December of 2005 reported that 26% of US households will own or will purchase a high-definition set by the end of 2006.

The NAB (National Association of Broadcasters) maintains a growing list of stations that have made the move to digital broadcast. In December 2005, 1,550 stations were broadcasting digitally.

European broadcasters are very interested in launching HDTV services based on a combination of new technologies → second generation HDTV coded at 7.5 Mbit/s using different video compression

schemes MPEG-4 AVC & Microsoft VC1 software decoding




Impact of HDTV

Broadcasters & consumers spend more $ Increased visual clarity has forced designers to

spend considerably more money on sets, set dressings and props

DVD battle being waged

Blu-Ray vs. HD-DVD




Final Words

As NTSC/PAL retires, HDTV programming, products, and production services will continue to grow exponentially.

Move will be cheaper, quicker, and easier as products and services become more widespread and people grow accustomed to the new technology.

HDTV has brought a more cinematic experience into viewer’s homes and with digital cinema, delivered the film industry a few of the benefits of television. However, HDTV still has much lower resolution than 70mm film. It’s a matter of time before some will begin pressuring for another increase in quality.





Documents

Taiwan DTV Committee 社團法人台灣數位電視協會 石佳相博士 台灣數位電視協會 常務理事 華電聯網 新媒體應用整合處 副總經理 2009.04.17 高畫質電視面面觀

Taiwan DTV Committee 社團法人台灣數位電視協會石佳相博士台灣數位電視協會常務理事華電聯網新媒體應用整合處副總經理 2009.04.17 高畫質電視面面觀