| Review 1: | Digital
Audio Broadcasting – Principles and Applications of Digital Radio, Edition
2 Wolfgang Hoeg and Thomas Lauterbach |
John Wiley & Sons
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| Review 2: |
H.264 and MPEG-4 Video Compression
- Video Coding for Next-generation Multimedia |
John Wiley & Sons
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Digital Audio Broadcasting – Principles and Applications of Digital Radio, Edition 2
As the first edition of the "DAB Book" was sold out within a year and a half of its publication, Wiley decided to publish a revised edition at the end of 2003. The publisher seems to be confident that the new edition will also sell well.
Following our review of the first edition about two years ago (click here), we have now had a chance to look at the second edition of this book. Our assessment of the first edition as a useful compendium of general information on the Eureka-147 broadcast system was largely positive. The second edition is even more complete and comprehensive, taking into account the most recent developments within the WorldDAB Forum.
Those broadcasters who have started DAB services will certainly appreciate this publication as an "all-in-one" handbook. It is well known that most of the ETSI technical standards and norms are almost unreadable for non-experts, or those engineers who could not be directly involved in the system developments. A book that is able to translate the official texts into a more "consumable" language is therefore very useful and helps to popularise the technology.
The main virtue of this book is therefore its straightforward, down-to-earth language – it easy to understand in the case of non-expert and non-English readers. It is commendable that the editors have been able to simplify the expert jargon produced by the invited authors, making the book very understandable to the non-initiated.
It is clear that the DAB system is evolving fast in the direction of becoming a multimedia carrier – DMB (Digital Multimedia Broadcasting). DMB widens the scope of DAB to carry not only audio but also various multimedia components including video. An addition of the Reed-Solomon channel protection layer may be required. Similar to the developments within DVB-H, an IP (internet protocol) layer could be integrated to provide service discovery and selection. This requires a bidirectional connection between the service provider and the user, via a mobile phone. To this end, a synergy between DMB and mobile telephony seems to be imminent.
These developments will help modernise the DAB system to become capable of embracing novel (and more efficient) audio/video coding standards. It is evident that MPEG Layer 2 has now become a quality bottleneck and a major obstacle in the commercial deployment of DAB . In the UK (and it many other countries) all the DAB spectrum capacity is used up with the existing services, forcing the broadcasters to use bitrates as low as 128 kbit/s or even lower, resulting in a very mediocre sound quality. Critics say that the sound quality provided in the UK by the Sky satellite service, the terrestrial DVB-T Freeview service, or even the Internet, is better than DAB.
The DAB system may evolve further by carrying multichannel sound such as 5.1 Dolby Digital, DTS, Windows Media or MPEG-4 AAC (H.264). Hooks should be provided to enable these systems to be included in the DAB system.
Any further editions of the "DAB Book" may wish to include these enhancements as well as tackle the important commercial issues and social impact. No longer is the technology a determining factor for the success of digital systems such as DAB. The DAB standard is certainly an impressive engineering achievement but its commercial success is not guaranteed.
It is probably true to say that, in DAB, the technology is way ahead of the commercial reality. There is a huge discrepancy between what could technically be done and what is actually happening on the market.
Excellent books such as this one can certainly help to promote DAB, but I doubt if they can turn DAB into a significant mass-market success.
Digital Audio Broadcasting – Principles and Applications
of Digital Radio
Wolfgang Hoeg and Thomas Lauterbach
Hard bound volume of 331 pages
ISBN 0-470-85013-2. Price: £65.00
John Wiley & Sons, 2003
http://www.wileyeurope.com/WileyCDA/WileyTitle/productCd-0470850132.html
Franc Kozamernik
H.264 and MPEG-4 Video Compression - Video Coding for Next-generation Multimedia
Digital video compression technologies have been developing intensely for more than two decades and, during this time, video codecs have become a cornerstone technology for efficient storage (on optical and magnetic devices such as CD, CD-ROM, DVD etc.) and transmission (e.g. broadcasting over satellite, cable, terrestrial, the internet, telecom networks etc.). Video compression reduces the number of bits used to represent each pixel in the image but introduces, to a lesser or greater extent, visible artefacts. More efficient compression systems introduce less visible artefacts and their quality depends less on the video content, but they are more complex and require more computation effort. There are many video compression formats available in the market today (e.g. MPEG-2 which has been used in digital TV and DVD for more than 10 years). These formats are either proprietary or standardized internationally, and many new formats are emerging.
This book is about the most recent development in video compression within the MPEG-4 family. The first member of this family is MPEG-4 Visual while the most recent is called "Advanced Video Coding" (AVC). The latter is also known as ITU-T Recommendation H.264 and as ISO/IEC 14496 (MPEG-4) Part 10. The international standardization work on H.264 was completed in July 2003. This left very little time for the author, Iain Richardson, to produce and publish this book. The timeliness of the book is just remarkable.
In addition to its good timing, the book has a number of interesting attributes which make it highly recommendable. First of all, it contains a very clear tutorial on the basics of video compression. Notions such as motion-compensated prediction coding, transform coding and entropy coding are explained at a good academic level. A good number of examples help to illustrate the point. After this introductory part, the author gives a thorough description of both MPEG-4 Part 2 Video and H.264, and highlights the main differences between the two.
Of particular value are the last three chapters which are devoted to H.264. Chapter 6 describes the three profiles that are standardized: the baseline profile, the main profile and the extended profile. The range of available coding tools (profiles) is more restricted than MPEG-4 Visual, due to the narrower focus of H.264, but there are still many possible choices of coding parameters and strategies.
Chapter 7 examines design issues for each of the main functional blocks of the H.264 codec, and compares the performance of MPEG-4 Visual with H.264. This chapter shows, and later ITU studies confirm, that H.264 has the ability to outperform MPEG-4 Visual convincingly (which in turn performs better than MPEG-2). Quality performance is but one factor that influences whether a new technology is successful in the marketplace. Other non-technical factors (discussed in chapter 8 of the book) involve selected topics such as industry support for the codec, availability of tools and costs, compliance with the standard and the successful resolution of the contentious topic of patent licensing.
It should be stressed that the patent licensing of H.264 is still an open issue, in spite of its lengthy process. Some significant efforts by MPEG LA, the organization in charge of the licensing matters, have been made during recent months, particularly in meeting the requirements of Japanese content providers in the mobile phone environment. But many questions still remain unresolved. These are potentially very damaging for the commercial success of H.264.
From the technology point of view, the H.264 standard could undoubtedly become a cornerstone video coding format for all multimedia applications in future "green field" broadcasting and telecom delivery channels. The flexible usage of H.264, ranging from very low bitrate applications (e.g. in video telephony) to future high bitrate applications (such as HDTV broadcasting) has been demonstrated.
However, there are many questions seeking clarification, as follows:
In conclusion, this book is a fascinating attempt to explain the
fundamentals of MPEG-4 video technologies and to put them in context with the
goals of the ever-changing market.
The book is highly recommended for broadcast engineers involved in digital television, multimedia production and transmission.
H.264 and MPEG-4 Video Compression – Video Coding
for Next-generation Multimedia
Ian E.G. Richardson
Hard bound volume of 281 pages
ISBN 0-470-84837-5. Price: £55.00.
John Wiley & Sons, 2003
http://www.wileyeurope.com/WileyCDA/WileyTitle/productCd-0470848375.html
Franc Kozamernik
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