Newnes Guide to Digital TV Newnes Guide to Digital TV Richard Brice OXFORD AMSTERDAM BOSTON LONDON NEW YORK PARIS SAN DIEGO SAN FRANSISCO SINGAPORE SYDNEY TOKYO Second edition Newnes An imprint of Elsevier Science Linacre House, Jordan Hill, Oxford OX2 8DP 200 Wheeler Road, Burlington, MA 01803 First published 2000 Second edition 2003 Copyright # 2000, 2003, Richard Brice. All rights reserved No part of this publication may be reproduced in any material form (including photocopying or storing in any medium by electronic means and whether or not transiently or incidentally to some other use of this publication) without the written permission of the copyright holder except in accordance with the provisions of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London, England W1T 4LP. Applications for the copyright holder’s written permission to reproduce any part of this publication should be addressed to the publishers British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library ISBN 0 7506 5721 9 For information on all Newnes publications, visit our website at www.newnespress.com Data manipulation by David Gregson Associates, Beccles, Suffolk Printed and bound in Great Britain by Antony Rowe Ltd., Chippenham, Wiltshire Preface to the second edition xiii Preface to the first edition xv 1 Introduction 1 Digital television 1 Why digital? 1 More channels 3 Wide- screen pictures 3 Cinema sound 4 Associated services 4 Conditional access 6 Transmission techniques 6 Receiver technology 6 The future . . . 7 2 Foundations of television 8 A brief history of television 8 The introduction of colour 9 The physics of light 9 Physiology of the eye 10 Psychology of vision ^ colour perception 12 Metamerism ^ the great colour swindle 13 Persistence of vision 14 The physics of sound 14 Fourier 16 Transients 16 Physiology of the ear 17 Psychology of hearing 18 Masking 19 Temporalmasking 20 Film and television 21 Television 22 Television signals 24 H sync and V sync 24 Colour television 26 NTSC and PAL colour systems 27 SECAMcolour system 31 Shadowmask tube 32 Vestigial sideband modulation 33 Audio for television 34 NICAM728 digital stereo sound 35 Recording television signals 35 Colour under 36 Audio tracks 38 Timecode 38 Longitudinal timecode 38 Vertical interval timecode (VITC) 40 PAL and NTSC 40 User bits 40 TeletextTM 40 Analogue high definition television ( HDTV) 41 MAC 43 PALplus 43 1125/ 60 and 1250/ 50 HDTV systems 44 1250/50 European HDTV 44 625- line television wide screen signalling 44 TheWSS signal 44 Data structure 44 Display formats 46 Telecine and  pulldown 46 3 Digital video and audio coding 50 Digital fundamentals 50 Sampling theory and conversion 51 Theory 51 Themechanismof sampling 53 Aliasing 54 Quantization 54 Digital-to-analogue conversion 55 Jitter 56 Aperture effect 56 Dither 56 Digital video interfaces 57 Video timing reference signals (TRS) 59 Clock signal 61 Filter templates 61 Parallel digital interface 62 Serial digital interface 63 HDTV serial interface 65 Digital audio interfaces 66 AES/EBU or IEC958 type 1 interface 66 SPDIF or IEC958 type 2 interface 67 Data 68 Practical digital audio interface 70 TOSlink optical interface 70 Unbalanced (75 ohm) AES interface 71 Serial multi- channel audio digital interface ( MADI) 72 Data format 73 Scrambling and synchronization 76 Electrical format 77 Fibre optic format 77 Embedded audio in video interface 77 Error detection and handling 80 EDH codeword generation 81 EDH flags 83 4 Digital signal processing 85 Digital manipulation 86 Digital filtering 86 Digital image processing 88 Point operations 88 Window operations 89 Transforming between time and frequency domains 93 Fourier transform 93 Phase 95 Windowing 96 2- D Fourier transforms 98 More about digital filtering and signal processing 99 Convolution 100 Impulse response 100 FIR and IIR filters 101 Design of digital filters 102 Frequency response 103 Derivation of band-pass and high-pass filters 105 Designing an IIR filter 106 IIR filter design example 107 High-pass filter example 109 Digital frequency domain analysis ^ the z- transform 110 Problems with digital signal processing 110 5 Video data compression 112 Entropy, redundancy and artefacts 112 Lossless compression 113 De-correlation 114 Lossless DPCM and lossy DPCM 116 Frame differences and motion compensation 117 Fourier transform- based methods of compression 119 Transform coding 119 A practicalmix 123 JPEG 125 Motion JPEG ( MJPEG) 127 MPEG 127 Levels and profiles 128 Main profile atmain level 129 Main level at 4 : 2 : 2 profile (ML@4 : 2 : 2P) 129 Frames or fields 129 MPEG coding 131 Mosquito noise 135 MPEG coding hardware 135 Statisticalmultiplexing 136 DV, DVCAM and DVCPRO 137 6 Audio data compression 139 Compression based on logarithmic representation 139 NICAM 140 Psychoacoustic masking systems 140 MPEG layer I compression (PASC) 141 MPEG layer II audio coding (MUSICAM) 142 MPEG layer III 143 Dolby AC- 3 143 7 Digital audio production 145 Digital line- up levels and metering 145 The VUmeter 146 The PPMmeter 147 Opto-electronic level indication 148 Standard operating levels and line- up tones 149 Digital line-up 149 Switching and combining audio signals 150 Digital audio consoles 151 Soundmixer architecture 151 Mixer automation 152 Digital tape machines 153 Digital two-track recording 153 Digitalmulti-tracks 154 Digital audio workstations 155 Audio file formats 156 WAV files 156 AU files 157 AIFF and AIFC 157 MPEG 157 VOC 158 Raw PCMdata 158 Surround- sound formats 158 Dolby Surround 158 Dolby digital (AC-3) 161 Rematrixing 161 Dynamic range compression 161 MPEG-II extension tomulti-channel audio 162 Pro logic compatibility 162 IEC 61937 interface 162 Dynamic range compression 163 Multilingual support 163 EditingMPEG layer II audio 163 8 Digital video production 164 Swi4tching and combining video signals 164 Digital video effects 166 What is a video transition? 166 The cut 167 The dissolve 167 The fade 169 Wipes 169 Split-screens 170 Keys 170 Posterize 171 Chroma-key 172 Off- line editing 174 Computer video standards 175 Vector and bitmap graphics ^ whats the difference? 177 Graphic file formats 178 Windows Bitmap (.BMP) 179 PCX 179 TARGA 179 GIF 179 JPEG 180 Computer generated images (CGI) and animation 180 Types of animation 181 Software 182 2D systems 182 Paint-system functions 182 Compositing 188 Morphing and warping 189 Rotorscoping 190 3D graphics and animation 191 Matrices 192 Imaging 194 Light 195 Ray tracing 197 Hard disk technology 198 Winchester hard disk drive technology 199 [...]... transformation – from analogue to digital But what exactly does digital television mean to you and me? What will viewers expect? What will we need to know as technicians and engineers in this new digital world? This book aims to answer these questions For how and where, refer to Figure 1.1 – the Newnes Guide to Digital Television route map But firstly, why digital? Why digital? I like to think of the gradual... writing Newnes Guide to Digital Television earlier than I did But I don’t think it’s just retrospective justification to say that I hesitated because, even a short time ago, many technologies that are today’s reality were still in the laboratory and research information was very thin indeed There has therefore been the need to make up for lost time in the publishing phase I should also like to thank... Great Coxwell 2002 Preface to the first edition Newnes Guide to Digital Television is written for those who are faced with the need to comprehend the novel world of digital television technology Not since the 1960s – and the advent of colour television in Europe – have managers, technicians and engineers had to learn so much, so quickly; whether they work in the development laboratory, the studio or in... different The term 16 Newnes Guide to Digital TV Figure 2.5 Guitar waveform we use to describe the character of the sound is ‘timbre’, and the timbre of a sound relates to these extra movements which superimpose themselves upon the fundamental sinusoidal movement that determines the fundamental pitch of the musical note Fortunately these extra movements are amenable to analysis too; in fact, in a quite... width to height) for the motion picture industry was 4 : 3 According to historical accounts, this shape was decided somewhat arbitrarily by Thomas Edison while working with George Eastman on the first motion picture film stocks The 4 : 3 shape they worked with became the standard as the motion picture business grew Today, it is referred to as the ‘Academy Standard’ aspect ratio When the first 4 Newnes Guide. .. cannot hope to continue in the eclectic, diversified, channel-zapping, competitive world of today For this reason, all DTV systems include mechanisms for ‘conditional access’, which is seen as vital to the healthy growth of digital TV These issues too are covered in the pages that follow Transmission techniques Sadly, perhaps, just as national boundaries produced differing analogue systems, not all digital. .. of digital television would be woefully incomplete without a chapter devoted to receiver and set-top box technology as well as to digital versatile disc (DVD), which is ousting the long-treasured VHS machine and bringing digital films into increasing numbers of homes The future One experience is widespread in the engineering community associated with television in all its guises; that of being astonished... television; analogue and digital The physics of light When an electromotive force (EMF) causes an electric current to flow in a wire, the moving electric charges create a magnetic field around the wire Correspondingly, a moving magnetic field is capable of creating an EMF in an electrical circuit These EMFs are in the form of voltages constrained to 10 Newnes Guide to Digital TV dwell inside electric... suspensory ligament to flatten the lens in order to view distant objects, and relax to view near objects The iris, a circular membrane in front of the lens, is the pigmented part of the eye that we see from the outside The iris is the eye’s aperture control, and controls the amount of light entering the eye through the opening in the iris known as the pupil 12 Newnes Guide to Digital TV The light-sensitive... source (see Figure 2.2) Similarly, we may be hoodwinked into seeing light-blue cyan with the simultaneous activation of green and blue We can also be made to experience paradoxical colours like magenta by combining red and blue, a feat that no pure light Figure 2.2 Photochemical response of the chemicals in the eye 14 Newnes Guide to Digital TV source could ever do! This last fact demonstrates that . RAID 202 RAID 1 (mirroring) 203 RAID 2 (bit striping with error correction) 203 RAID 3 (bit striping with parity) 203 RAID 4 (striping with fixed parity) 204 RAID 5 (striping with striped. Newnes Guide to Digital TV Newnes Guide to Digital TV Richard Brice OXFORD AMSTERDAM BOSTON LONDON NEW YORK PARIS SAN DIEGO SAN FRANSISCO SINGAPORE SYDNEY TOKYO Second edition Newnes An imprint. of spending more time with them. Richard Brice Great Coxwell 2002 xiv Preface to the second edition Preface to the first edition Newnes Guide to Digital Television is written for those who are faced with the