The technology of video and audio streaming

The Technology of Video and Audio Streaming

Second Edition

The Technology of

Video and Audio

Streaming

Second Edition

David Austerberry

AMSTERDAM • BOSTON • HEIDELBERG • LONDON

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Focal Press is an imprint of Elsevier

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Copyright © 2005, David Austerberry. All rights reserved.

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Library of Congress Cataloging-in-Publication Data

Austerberry, David.

The technology of video and audio streaming / David Austerberry. – 2nd ed.

p. cm.

Includes bibliographical references and index.

ISBN 0-240-80580-1

1. Streaming technology (Telecommunications) 2. Digital video. 3. Sound –

Recording and reproducing – Digital techniques. I. Title.

TK5105.386 .A97 2004

006.7¢876 – dc22

2004017485

British Library Cataloguing-in-Publication Data

A catalogue record for this book is available from the British Library.

ISBN: 0240805801

For information on all Focal Press publications visit our website at

www.books.elsevier.com

04 05 06 07 08 09 10 9 8 7 6 5 4 3 2 1

Printed in the United States of America

Contents

Preface ix

Acknowledgments xi

Section 1. Basics 1

1 Introduction 3

500 years of print development 3

100 years of the moving image 4

The Web meets television 5

Convergence 7

What is streaming? 7

Applications 9

How this book is organized 10

Summary 10

2 IP networks and telecommunications 13

Introduction 13

Network layers 14

Telecommunications 25

The local loop 30

Summary 38

3 The World Wide Web 40

Introduction 40

WWW 42

Web graphics 44

Proprietary tools 48

Web servers 48

Summary 51

4 Video formats 52

Introduction 52

Scanning 53

Color space conversion 56

Digital component coding 61

Videotape formats 65

Time code 72

Interconnection standards 74

High definition 76

Summary 77

5 Video compression 78

Introduction 78

Compression basics 79

Compression algorithms 80

Discrete cosine transform 84

Compression codecs 87

MPEG compression 89

Proprietary architectures 98

Summary 101

6 Audio compression 102

Introduction 102

Analog compression 103

Digital audio 104

The ear and psychoacoustics 110

The human voice 112

Lossy compression 114

Codecs 117

Codec standards 118

Proprietary codecs 127

Open-source codecs 128

Summary 129

Section 2. Streaming 131

7 Introduction to streaming media 133

Introduction 133

What are the applications of streaming? 134

The streaming architecture 138

Bandwidth, bits, and bytes 147

vi Contents

Proprietary codec architectures 149

Summary 152

8 Video encoding 154

Introduction 154

Video capture 159

Compression 167

Encoding enhancements 170

Encoding products 173

Limits on file sizes 175

Summary 177

9 Audio encoding 179

Introduction 179

Audio formats 181

Capture 184

Encoding 186

File formats 189

Summary 192

10 Preprocessing 193

Introduction 193

Video processing 193

Audio 200

Summary 207

11 Stream serving 209

Introduction 209

Streaming 211

Webcasting 218

On-demand serving 222

Inserting advertisements 222

Playlists 224

Logging and statistics 225

Proprietary server architectures 227

Server deployment 229

Summary 232

12 Live webcasting 233

Introduction 233

Planning a webcast 233

Video capture 237

Contents vii

Graphics 238

Audio capture 238

Encoding 241

Summary 243

13 Media players 244

Introduction 244

Portals, players, and plug-ins 245

Digital Rights Management 256

Summary 257

Section 3. Associated Technologies and Applications 259

14 Rights management 261

Introduction 261

The value chain 264

Digital Rights Management 265

The rights management parties 270

System integration 274

Encryption 276

Watermarking 277

Security 279

XrML 280

Examples of DRM products 282

MPEG-4 286

Summary 287

15 Content distribution 289

Introduction 289

Content delivery networks 291

Corporate intranets 300

Improving the QoS 304

Satellite delivery 306

Summary 307

16 Applications for streaming media 309

Introduction 309

Summary 322

Glossary 327

Abbreviations 331

Index 335

viii Contents

Preface

The first edition of this book came about because I had made a career move

from television to streaming media. Although it was still video, streaming

seemed like a different world. The two camps, television and IT, had evolved

separately. It was not just the technology. It was the work practices, the jargon

– everything was different. I soon found that the two sides often misunderstood

each other, and I had to learn the other’s point of view. What I missed was a

top-down view of the technologies. I knew I could get deep technical informa￾tion about encoding, setting up servers, distribution networks. But for the busi￾ness decisions about what to purchase I did not need such detail – I wanted

the big picture. I found out the hard way by doing all the research. It was just

one more step to turn that information into a book.

As with any technology, the book became outdated. Companies closed down

or were bought out. The industry has consolidated into fewer leading suppliers,

but what a potential purchaser of systems needs are stable companies that are

going to be around for support and upgrades.

The second edition brings the information up to date, especially in the areas

of MPEG-4, Windows Media, Real, and Apple QuickTime.

Much has happened since I wrote the first edition of this book. There has

been an expansion across the board in the availability of network bandwidth.

The price of fiber circuits is decreasing. Within corporate networks, it is becom￾ing normal to link network switches with fiber. Gigabit Ethernet is replacing

10baseT. In many countries, the local loop is being unbundled. This gives the

consumer a choice of ADSL providers. They may also have the option of data

over cable from the local cable television network. All this competition is driving

down prices.

As third-generation wireless networks are rolled out, it becomes feasible to

view video from mobile appliances. These new developments are freeing the

use of streaming technology from just the PC platform. Although the PC has

many advantages as a rich media terminal, the advent of other channels is

increasing its acceptance by corporations.

There are still many hurdles. Potentially, streaming over IP offers cable tele￾vision networks a means to deliver video on demand. One problem is that there

is an installed base of legacy set-top boxes with no support for video over IP.

Another problem is the cost of the media servers.

What will all this universal access to video-on-demand mean? Since the dawn

of television, video has been accepted as a great communicator. The ability of

a viewer to choose what and when they want to watch has presented many

new opportunities. For government, it is now possible for the public to watch

proceedings and committees. Combined with e-mail, this provides the platform

to offer ‘open government.’ The training providers were early adopters of

streaming, which transformed the possibilities for distance learning by the addi￾tion of video. The lecturers now had a face and a voice.

For the corporation it adds another channel to their communications to staff,

to investors, and for public relations. Advertisers are beginning to try the

medium. A naturally conservative bunch, they have been wary of any techno￾logical barriers between them and the consumer. The general acceptance of

media plug-ins to the Web browser now makes the potential audience very

large. The content delivery networks can stream reliable video to the consumer.

The advertisers can add the medium to existing channels as a new way to reach

what is often a very specific demographic group.

This edition adds more information on MPEG-4. When I wrote the first edition,

many of the MPEG-4 standards were still in development. In the intervening

period the advanced video codec (AVC), also known as H.264, has been devel￾oped, and through 2004 will be released in many encoding products. Microsoft

has made many improvements to Windows Media, with version 9 offering very

efficient encoding for video from thumbnail size up to high-definition television.

Microsoft also submitted the codec to the SMPTE (Society of Motion Picture

and Television Engineers) for standardization as VC-9. Windows Media Player

10 adds new facilities for discovering online content.

The potential user of streaming has a choice of codecs, with MPEG-4 and

Windows Media both offering performance and facilities undreamt of ten years

ago. I would like to thank Envivio and their UK reseller, Offstump, for help with

information on MPEG-4 applications, with a special mention for Kevin Steele.

Jason Chow at TWIinteractive gave me a thorough run-down on the Interac￾tive Content Factory, an innovative application that leverages the power of

streaming.

David Austerberry, June 2004

x Preface

Acknowledgments

The original idea for a book stemmed from a meeting with Jennifer Welham of

Focal Press at a papers session during an annual conference of the National

Association of Broadcasters. I would like to thank Philip O’Ferrall for suggest￾ing streaming media as a good subject for a book; we were building an ASP to

provide streaming facilities. I received great assistance from Colin Birch at Tyrell

Corporation, and would like to thank Joe Apted at ClipStream (a VTR company)

for the views of an encoding shop manager. I am especially grateful to Gavin

Starks for his assistance and for reading through my draft copy.

The web sites of RealNetworks, Microsoft, and Apple have provided much

background reading on the three main architectures.

While I was undertaking the research for this book I found so many dead links

on the Web – many startups in the streaming business have closed down or

have been acquired by other companies. I wanted to keep the links and refer￾ences up to date in this fast-changing business, so rather than printing links in

the text, all the references for this book are to be found on the associated web

site at www.davidausterberry.com/streaming.html.

Section 1

Basics