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Making sense out of complex Pro A/V and Broadcast technologies.

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An educational resource published by Communications Specialties, Inc..

HDTV Standards and Practices

for Digital Broadcasting

A look at the SMPTE standards that define SD, HD

and Fiber Optic Signal Distribution, what the standards

mean, and why they are important to you.

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Guide

Making sense out of complex Pro A/V and Broadcast technologies.

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©2009 Communications Specialties, Inc. All Rights Reserved.

Specifications, claims or other product information contained in this document are subject to

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Fiberlink, Pure Digital Fiberlink, the starburst logo, Scan Do and Deuce are registered trademarks

of Communications Specialties, Inc. CSI and the triangle designs are trademarks of

Communications Specialties, Inc.

October 8, 2009



Introduction

This eduGuide is intended for the video professional that is starting to

become involved with designing, specifying, operating or maintaining digital

video broadcast and distribution systems for HDTV. For over 50 years our

industry has used television technology of a primarily analog nature. True,

some digital technology has been used in broadcast facilities for standard

definition or NTSC and PAL systems, but its deployment has been limited and

ultimately converted back to an analog signal for distribution and broadcast.

Today, HDTV is the first broadcast technology designed to be exclusively

digital from image capture to display on the consumer’s TV set. Many

different technologies are used where the video, and audio, undergoes

many transformations from start to finish. This eduGuide will help you to

understand the chain of technologies used, the industry standards behind

them, for both copper and fiber optic distribution, and the practices video

professionals are developing for the new world of HDTV.

The Role of Technical Standards

The broadcast industry, unlike the A/V and computer industries, has

historically been a proponent and practitioner of technical standards for video

and audio processing and distribution. The reason is simple: interoperability.

The broadcaster, and those in related professional video industries, need

to be able to select the best equipment for the task at hand. Since all the

equipment in a distribution or edit suite will need to process the same

video and audio, there is a need to define and adhere to interface standards

between the various pieces of equipment.

There are several technical standards organizations in the world that

develop and promote these standards but perhaps the most noted is

SMPTE. The Society of Motion Picture and Television Engineers (SMPTE) has

membership and participation from individuals, broadcasters and equipment

manufacturers from around the world. The expertise and experience brought

to bear by this group creates a forum for developing very powerful and

lasting standards.

The buyer and user of broadcast equipment is the ultimate beneficiary of this

process. He can be assured that products compliant with a particular set of

standards will allow video and audio signals to be communicated between

them in a recognizable way without requiring additional processing or

interfacing. The benefit to the user is lower design and operational costs and

a wider selection of equipment to choose from for a particular application

without being locked in to any one equipment manufacturer employing

proprietary interfaces and protocols.

HDTV Standards and Practices for Digital Broadcasting

3



SDTV Standards for Video

We will begin our discussion of HDTV standards with a review of Standard

Definition (SD) standards. It is from these SD standards that the HD standards

were developed. For over 50 years, the transmission of television video and

audio was done in an analog fashion. Worldwide analog standards included

NTSC, PAL and SECAM with varying amounts of active scan lines, spatial

timings and color encoding schemes.

A need arose to create standards for a digital representation of these analog

TV systems in order to facilitate editing, recording and complex routing

without degrading the original material. It was also important to insure that

these new digital standards would be compatible with the analog standards

to facilitate transcoding and eventual broadcast to consumers without

obsolescing their TV sets.

Several standards were developed to digitally represent SD video:

ITU-R BT.601 (a.k.a “601”):

This standard defines how video luminance and

color information is digitized. It defines the range of binary values for 8 and

10-bit quantization of luminance and the two color difference signals that

together define the brightness, color saturation and color hue of the video. It

is used to quantize both the NTSC and PAL SD timings. Luminance is sampled

720 times per horizontal line and color is sampled 360 times per line. Keep

in mind that 601 only defines the spatial sampling and not any physical

interface. 601 can be communicated in a bit-parallel or bit-serial manner. The

latter being the most popular, which uses the SMPTE 259M standard.

SMPTE 259M-2008 (a.k.a. “SDI” or “259”):

When 601 is bit-serialized

and transmitted over a copper interface it is done according to the SMPTE

259M-2008 standard. SDI is the abbreviation for Serial Digital Interface. In

general, the term SDI can refer to any television standard that is digitized and

then serially transmitted and, up until recently, only referred to SD resolutions.

However, with HDTV in more common use, we now refer to the standard

definition version of SDI as SD-SDI. 259 defines important parameters of

the serial digital signal such as bit jitter, data rate, rise and fall time, signal

amplitude and connector impedances.

AES3-2003 (a.k.a “AES Audio”):

When analog line level audio is digitized,

it is done according to the AES3-2003 standard. The AES Audio standard

defines the number of bits the audio is quantized into and the sampling rate

of the quantization.

SMPTE 272M-2004 and 291M-2006:

SMPTE 272M-20004 defines how the

AES Audio bits are mapped into another standard called SMPTE 291M-2006.

291M defines how audio, ancillary data and synchronization information is

encoded within the SMPTE 259M standard and other high definition and

cinema standards.

4

HDTV Standards and Practices for Digital Broadcasting



How the SMPTE SDTV Standards Combine:

SMPTE 259

Coaxial

Cable

SMPTE 291M

BT. 601 (Video)

SMPTE 272M

AES3-2003 (Audio)

HDTV Standards and Practices for Digital Broadcasting

5



HDTV Standards for Video

The standards for HDTV have many roots. Early HDTV standards go back to

the 1980s when HDTV was defined using analog techniques. But today, HDTV

is primarily a digital technology using an array of standards for both video and

audio.

Video HDTV standards define both the color gamut and spatial resolution of

the image. Color gamut, the array or palette of colors that are possible and

valid for a video signal, is different in HD than in SD television allowing for

slightly deeper green and red hues.

ITU-R BT.709 (a.k.a “709”):

This standard defines how video luminance and

color information is digitized for HDTV. It defines the range of binary values

for 8, 10 and 12-bit quantization of luminance and the two color difference

signals that together define the brightness, color saturation and color hue

of the video. It also defines the algebraic formula matrix for converting from

RGB color space into luminance and color difference signals. These formulas

vary slightly from the “601” formula matrix. The actual number of samples

per line will vary depending on the spatial resolution of the HD format being

used.

SMPTE 274M-2008:

This HD standard defines the 1920x1080 spatial

resolution (image sample structure) and several frame rates for this resolution.

1920 pixels define the active number of pixels per line and 1080 lines are

the active number of lines per frame. Frame rates can be either interlaced or

progressive. Special consideration is given to NTSC frame rate compatibility

by defining 60, 30 and 24 hertz frame rates which are divided by 1.001. This

allows genlocking HD signals to NTSC references and is in common use in

NTSC facilities.

SMPTE 296M-2001:

This HD standard defines the 1280x720 spatial

resolution at various frame rates. All frame rates are progressive only.

There are 1280 active pixels per line and 720 active lines per frame. Special

consideration is given to NTSC frame rate compatibility by defining 60, 30 and

24 hertz frame rates which are divided by 1.001.

SMPTE 240M-1999 and 260M-1999:

These two HD standards describe a HD

spatial resolution consisting of 1125 total lines per frame of which 1035 lines

are active. The 240M standard defines the analog representation of the signal

and 260M defines the digital representation. In both cases, an interlaced

frame is used with a vertical sync frequency of either 60 hertz or 60/1.001

hertz to match NTSC. Also, these use the 601 color space conversion matrix

and not the 709 matrix. When the 260M analog representation is digitized

according to 260M, it can quantized into either 8 or 10 bits per pixel. There

are 1920 active pixels per line.

SMPTE 292-2008 (a.k.a. “HD-SDI” or “292”):

This standard defines how

the signals defined by 274M, 296M and 260M are transmitted in a bit-serial

6

HDTV Standards and Practices for Digital Broadcasting



fashion at an approximate data rate of 1.5 Gbps over coaxial cable. It does not

define the resolution of the video image defined in other standards, including

those for audio and data embedded within the video, but rather how they

are to be communicated. SMPTE 292 is just a transport stream and physical

layer interface definition for coaxial cable. Please note that 292 only supports

1080i (interlaced) frames at 50, 59.94 and 60 Hertz on a single 292 interface.

In order to support 1080p (progressive) frame rates 50 Hertz and above, either

two 292 interfaces must be used in parallel, as defined by SMPTE 372M, or one

SMPTE 424 interface can be used. 292 and 424 define important parameters

of the serial digital signal such as bit jitter, data rate, rise and fall time, signal

amplitude and connector impedances.

SMPTE 424M-2006:

This standard defines the bit serial structure using a

coaxial interface at a nominal bit rate of 3 Gbps for component digital video

and other packetized data. The actual data rate used is either 2.97 Gbps or

2.97/1.001 Gbps with the later being used to synchronize to NTSC references.

The significance of this standard is that it defines how 1080p at frame rates

from 50 to 60 Hertz are to be transmitted over a single coaxial cable. This

standard is now gaining in use instead of the 372 standard as it requires only

one signal path.

Ancillary Data Packets

Audio data, format ID and time code are just some of the information types

that can be accommodated within both SD and HD standards. Data for this

information is inserted into the streams during the horizontal and vertical

blanking times of the image raster. Here is a brief look at some of the SMPTE

standards for this information:

SMPTE 291M-2006:

This standard describes the basic formatting structure

of an ancillary data space for insertion into 259 and 292. The ancillary data

packets that can occupy this data space can contain audio, data, time code,

program ID information or other data. Think of 291 as a basket into which

we can place various information for transport. The 291 basket can then be

carried by various means, such as 259 and 292.

SMPTE 299-2009:

This standard describes how 24-bit AES audio is mapped

into the 291 data space for use with a 292 HD-SDI signal. Audio channels are

transmitted in groups of four up to a maximum of 16 audio channels. A 48

kbps sample rate is used. Using this standard with 292 is often referred to as

“embedded audio”.

SMPTE 352M-2002:

This standard defines the video payload identifier

information. It is a 4-byte identifier that may be added to 291 to identify the

video signal being transmitted in 259 or 292.

The chart on the following page shows how these standards combine:

HDTV Standards and Practices for Digital Broadcasting

7



How the SMPTE HDTV Standards Combine:

SMPTE 292

or

SMPTE 424M

Coaxial

Cable

SMPTE 291M

SMPTE 299M

SMPTE 352M

AES3-2003

(Audio)

SMPTE 274M

SMPTE 296M

SMPTE 240M

BT. 709 (Video)

8

HDTV Standards and Practices for Digital Broadcasting



Fiber Optic Transport of 3G/HD/SD-SDI

It is becoming increasingly necessary and economically feasible to transport

3G/HD/SD-SDI signals over fiber instead of coaxial cable. The reasons are

m0ds were used to define how SDI signals were to be transported over fiber.

Now, there is one standard to define the many aspects and parameters of the

fiber optic interface for the transmission and reception of SDI over fiber.

SMPTE 297-2006:

This standard defines the fiber optic interface for the

transmission and reception of SDI signals at various data rates:

SMPTE 259M:

SMPTE 344M:

SMPTE 292:

SMPTE 424M:

143 through 360 Mbps

540 Mbps

1.485 and 1.485/1.001 Gbps

2.97 and 2.97/1.001 Gbps

SMPTE 297-2006 defines many parameters of the optical interface for both

a transmitting and receiving device with a fiber optic interface. The input

to a fiber Transmitter can be any one of the SMPTE coaxial-based standards

indicated above. On the Receiver, the output will be of the same coaxial

interface type of the Transmitter. The significance of the new 297 standard is

that it allows for interoperability between fiber optic devices from different

manufacturers that comply with the standard. Historically, fiber optic

interfaces for the transmission of video and audio used proprietary protocols

and optical interfaces which required that both the Transmitter and Receiver

be purchased from the same manufacturer. When using devices that are

compliant with the new 297 standard this is no longer required.

The Fiber Optic Transmitter:

SMPTE 297-2006 defines many parameters for

the optical output of the Transmitter. Among the most important are:

Optical Connector: The LC connector is the preferred connector with a PC

polish to the tip of the connector. Other connector types are optional but as a

practical matter, the Broadcast industry is embracing the LC connector.

Optical Power Output: The standard recognizes that fiber will be used for

various transmission distances and classifies Transmitter optical power

into Low-power, Medium-power and High-power categories. Low-power

Transmitters must support both single mode and multimode fiber types

whereas Medium and High power Transmitters need only support single

mode fiber. The maximum and minimum Transmitter output power is

specified for each category.

Transmitter Product Labeling: Because transmitters and receivers from

different manufacturers that comply with this standard can be interfaced to

each other, a standardized product labeling scheme is defined within SMPTE

297. The labeling scheme defines the power category of the transmitter, the

polish of the connector, the SMPTE coaxial interface standards supported and

the optical wavelength of the output. It should be noted that a SMPTE 297-

HDTV Standards and Practices for Digital Broadcasting

9



2006 Transmitter need not support all possible data rates.

The Fiber Optic Receiver:

SMPTE 297-2006 also defines the optical

properties for the input to the Receiver.

Optical Connector: The LC connector is the preferred connector with a PC

polish to the tip of the connector. Other connector types are optional but as a

practical matter, the industry is embracing the LC connector.

Supported Data Rates: A compliant Receiver can support any or all of the data

rates specified by the four electrical interface standards cited above.

Optical Receive Power: The standard specifies the minimum optical input

power a compliant receiver must support for the various data rates. A receiver

can be more sensitive, that is capable of accepting a weaker optical signal,

than the standard specifies. Also, the standard states the minimum optical

power that a receiver must accept before going into saturation (overload).

Note that this is independent of the wavelength and fiber cable type used.

Receiver Product Labeling: The labeling scheme for the Receiver indicates the

type of polish used on the input fiber connector, the SMPTE coaxial standards

supported and the range of wavelengths supported at the optical input.

Optical System Specifications:

In addition to specifying the Transmitter and

Receiver interfaces individually, SMPTE 297-2006 gives guidance on how a

compliant Transmitter and Receiver should work as a system pair. Among the

parameters specified are:

The minimum optical loss budget allowed based on the fiber type used,

the power rating of the Transmitter and the operating wavelength of the

Transmitter.

The minimum expected transmitter distance is also specified based on the

same parameters. However, it should be noted that depending on exactly

how the fiber cable is installed, i.e. how many splices and patch panels

are used, the minimum transmitting distance may not be achieved even

though the optical loss budget is not exceeded. This is especially true when

multimode fiber is used as optical dispersion in the fiber will result in very

poor bandwidth.

Although not stated in the SMPTE standard, it has been the experience of

CSI to recommend the use of single mode fiber for SDI transmission of video

signals. This ensures minimum optical signal loss, maximum transmission

distance compared to multimode fiber and the ability to multiplex multiple

optical signals onto one fiber with ease.

How the SMPTE Transport Standards Combine

for a Fiber Optic Interface

10

HDTV Standards and Practices for Digital Broadcasting



SMPTE 297

Fiber

Optic

Cable

SMPTE 259M

SD-SDI

SMPTE 344M

SDTI

SMPTE 292

HD-SDI

SMPTE 424M

3G-SDI

Conclusions

The use and deployment of standards in the manufacture of equipment and

specification of broadcast distribution systems is critical for today’s digital

HDTV and mixed HD/SD facilities. Fortunately, SMPTE and other standards

organizations have given the professional video community a precise way

of ensuring that equipment from various manufacturers will interoperate

correctly and predictably. As the industry moves from coaxial cable to fiber

optics, a defined standard has emerged to allow this interoperability to

extend to this high bandwidth medium.

HDTV Standards and Practices for Digital Broadcasting

11



Other issues in the eduGuide Series

Introduction to Fiber Optics

Indisputably, fiber is the future. Learn all about the benefits

of fiber optic technology in this easy-to-read guide.

Advantages of Digital Fiber Optics

Examines how transmitting digitally over fiber are accomplished,

the phenomenal results it achieves, and how cost-effective it is.

Fiber Optic Cables, Connectors and Integration

Learn how easy it is to terminate and fabricate your own fiber optic cables,

what types of fiber and fiber jackets are available and how to design

and integrate a fiber optic system.

Scan Converters Buyer’s Guide

Everything you need to evaluate and decide on the perfect Scan Converter.

Video Scaling

A comprehensive overview of the technology, how it works

and when to use this technology effectively.

Advanced Video Scaling

Easy explanations of Inverse 3:2 Pulldown, Anamorphic Scaling and Other

Confusing Concepts.

Other Educational Resources

commspecial.com

Visit our website for online education resources, product literature and more!

Pure Digital Fiberlink® Application Brief – Everyday Pro A/V

This application brief illustrates the benefits of using Pure Digital Fiberlink®

in any Pro A/V installation. Regardless of your Pro A/V market specialty,

this Application Brief is a valuable guide to integrating and specifying

Pure Digital Fiberlink® products.

Pure Digital Fiberlink® Intelligence Brief – Government/Military

Detailed analysis of how Pure Digital Fiberlink® has become the solution of

choice for mission critical government, intelligence and military applications.

If you are involved in this market segment, this document will prove to be

valuable during your next project specification.

12

HDTV Standards and Practices for Digital Broadcasting



HDTV Standards and Practices for Digital Broadcasting

13



About Communications Specialties, Inc.

Communications Specialties, Inc. (CSI) is an award-winning, Long Island

based company that manufactures and sells a variety of products for the

distribution, conversion or transmission of television and computer video

signals, including fiber optic transmission systems, scan converters and video

scalers.

The company was founded in 1983 by veterans of the broadcast industry.

Since then, CSI has managed to consistently design innovative products that

are used worldwide by Fortune 500 Companies and Government Agencies in

a variety of markets such as Broadcast, Professional A/V, Videoconferencing,

Education, Home Theater, Security, ITS, Industrial Monitoring, Digital Signage,

Government/Military and more!

The

Pure Digital Fiberlink®

line offers an extensive and affordable family

of fiber optic transmission systems for the Professional A/V marketplace

and includes several ground-breaking products for the transmission of

high-resolution RGB signals. Systems for point-to-point and

point-to-multipoint signal distribution make these products highly

desirable for any Pro A/V applications.

Our premier product line, the

Scan Do®

family of computer to video scan

converters, has redefined industry standards in computer video to NTSC/

PAL technology with unsurpassed performance in its price range. All models

support high resolutions and refresh rates and are VGA and Mac® compatible.

The feature-rich and versatile Scan Do family offers the widest range of scan

converters on the market.

The award-winning,

Deuce®

video scalers convert NTSC and PAL to high-

resolution, non-interlaced video and offer a far superior and affordable

alternative to line doubling and quadrupling. The new generation of Deuce

products offer a wide range of non-interlaced resolutions and refresh rates

for every application, from professional A/V installations to home theater,

including a model designed especially for use with HDTV displays.

In addition, CSI manufactures a comprehensive selection of distribution

amplifiers, VGA monitor, keyboard and mouse extenders and accessories for

our entire product line.

14

HDTV Standards and Practices for Digital Broadcasting



Communications Specialties and its products have been the recipient of

numerous industry awards. In 2005, the Pure Digital Fiberlink® 7220 Series

for high-resolution RGB and Stereo Audio was honored as one of the AV

industry’s best technological innovations of the year by receiving a “rAVe

Radical Product of the Year” award as “Best New Analog Signal Processing

Product”. The rAVe email newsletter is published by professional audiovisual

industry veterans and is read industry-wide.

Among CSI’s many other awards are AV Video Magazine’s Platinum Award

(given to Scan Do® Ultra and Deuce®) and the Video Systems’ Vanguard Award

(given to Deuce).

The company is headquartered in the United States on Long Island, New York,

with Sales Offices in Florida, Indiana and Virginia. Research, development,

design, engineering, manufacturing and customer support operations

are performed at the New York headquarters. Other locations include

Communications Specialties Pte Ltd (CSPL) - a wholly owned subsidiary office

in Singapore that provides support to distributors in the Far East and Pacific

Rim.

Our in-house sales department handles complete product-line sales directly

to end-users as well as to an international network of representatives and

resellers. All of our products are backed by an exceptional warranty.



Learn

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