Foreword
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xvii
Most people first learn about a standard in publications other than the standard itself.
My personal belief is that if you want to know about a standard, you should also obtain a
copy of it, read it, and refer to that document alone as the ultimate authority on its content,
its boundaries, and its capabilities. No tutorial or overview presentation will provide all of the
insights that can be obtained from careful analysis of the standard itself.
At the same time, no standardized specification document (at least for video coding), can
be a complete substitute for a good technical book on the subject. Standards specifications are
written primarily to be precise, consistent, complete, and correct and not to be particularly
readable. Standards tend to leave out information that is not absolutely necessary to comply
with them. Many people find it surprising, for example, that video coding standards say almost
nothing about how an encoder works or how one should be designed. In fact an encoder is
essentially allowed to do anything that produces bits that can be correctly decoded, regardless
of what picture quality comes out of that decoding process. People, however, can usually only
understand the principles of video coding if they think from the perspective of the encoder, and
nearly all textbooks (including this one) approach the subject from the encoding perspective.
A good book, such as this one, will tell you why a design is the way it is and how to make
use of that design, while a good standard may only tell you exactly what it is and abruptly
(deliberately) stop right there.
In the case of H.264/AVC or MPEG-4 Visual, it is highly advisable for those new to the
subject to read some introductory overviews such as this one, and even to get a copy of an
older and simpler standard such as H.261 or MPEG-1 and try to understand that first. The
principles of digital video codec design are not too complicated, and haven’t really changed
much over the years – but those basic principles have been wrapped in layer-upon-layer of
technical enhancements to the point that the simple and straightforward concepts that lie at
their core can become obscured. The entire H.261 specification was only 25 pages long, and
only 17 of those pages were actually required to fully specify the technology that now lies at
the heart of all subsequent video coding standards. In contrast, the H.264/AVC and MPEG-4
Visual and specifications are more than 250 and 500 pages long, respectively, with a high
density of technical detail (despite completely leaving out key information such as how to
encode video using their formats). They each contain areas that are difficult even for experts
to fully comprehend and appreciate.
Dr Richardson’s book is not a completely exhaustive treatment of the subject. However,
his approach is highly informative and provides a good initial understanding of the key con-
cepts, and his approach is conceptually superior (and in some aspects more objective) to other
treatments of video coding publications. This and the remarkable timeliness of the subject
matter make this book a strong contribution to the technical literature of our community.
Gary J. Sullivan
Biography of Gary J. Sullivan, PhD
Gary J. Sullivan is the chairman of the Joint Video Team (JVT) for the development of the latest
international video coding standard known as H.264/AVC, which was recently completed as a
joint project between the ITU-T video coding experts group (VCEG) and the ISO/IEC moving
picture experts group (MPEG).
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更新于2024-07-29
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