Cliff Wootton – A Practical Guide To Video and Audio Compression

Автор: Cliff Wootton
Название книги: A Practical Guide To Video and Audio Compression
Формат: PDF
Жанр: Театр и Кино
Качество: Изначально компьютерное, E-book

Learn all about Codecs–how they work, as well as design and implementation with this comprehensive, easy-to-use guide to compression. After reading this book, you will be able to prepare and distribute professional audio and video on any platform including streamed to the web, broadcast on-air, stored in PVRs, Burned onto CD-ROMs or DVDs, delivered by broadband, or viewed in Kiosk applications, PDA devices, and mobile phones.

The last few years have been an extraordinary time for the digital video industry. Not long
before the turn of the millennium, digital video editing systems were expensive capital
items of equipment that only major broadcasters and production companies could afford.
To think that now the same capability is available in a laptop that you can buy off the shelf
and it comes with the software for something in the region of $1200 is amazing. This is a
capability we have dreamed about having on our desktops for 15 years. The price of the
hardware and software needed to run an entire TV broadcast service is now within the
reach of any organization or individual who cares to get involved.
Recall the boom in publishing that happened when the Apple LaserWriter was
launched with Adobe PostScript contained inside and those early page composition programs
enhanced what we were able to do with Word version 1 or MacWrite. We are now
at that place with digital media and while some people will create an unattractive mess
with these powerful tools, they will also enjoy themselves immensely and learn a lot at the
same time. Eventually, a few skilled people will emerge from the pack and this is where
the next generation of new talent will come from to drive the TV and film industry forward
over the next couple of decades.
When Joanne Tracey asked me to prepare a proposal for this book I realized (as had
most authors I have spoken to) that I didn’t know as much about the topic I was about to
write on as I thought I did. So this book has been a journey of exploration and discovery
for me, just as I hope it will be for you. And yet, we also don’t realize how much we do
already know, and I hope you will find yourself nodding and making a mental comment
to yourself saying “Yes—I knew that” as you read on.
We excel through the efforts of those around us in our day-to-day interactions with
them. I have been particularly lucky to enjoy a few truly inspirational years with a group
of like-minded people at the BBC. We all shared the same inquisitive approach into how
interactive TV news could work. Now that we have all gone our separate ways I miss
those “water cooler moments” when we came up with amazingly ambitious ideas. Some
of those ideas live on in the things we engineered and rolled out. Others are yet to develop
into a tangible form. But they will, as we adopt and implement the new MPEG-4, 7, and
21 technologies.
We are still at a very exciting time in the digital video industry. The H.264 codec is
achieving enormous potential and there is much yet to do in order to make it as successful
as it could be. Looking beyond that is the possibility of creating HDTV services and
interactive multimedia experiences that we could only dream about until now.
Video compression can be a heavy topic at the best of times and we cover a lot of
ground here. I thought the idea of illustrating the concept with a cartoon (see the first illustration
in Chapter 1) would be helpful, because this subject can be quite daunting and
I have purposely tried not to take it all too seriously. The cartoon is in order to disarm the
subject and make it as accessible as possible to readers who haven’t had the benefit of
much experience with compression.
In some chapters you’ll find a gray box with an icon on the left and a briefly encapsulated
hot tip. These have been placed so that they are relevant to the topic areas being
discussed but also to help you flick through the book and glean some useful knowledge
very quickly. They have come out of some of those brainstorming times when I discussed
digital video with colleagues in the various places I work and in online discussions. It’s a
bit of homespun wisdom based on the experiences of many people and intended to lighten
the tone of the book a little.
If you are wondering about the face on the cover, it is my daughter Lydia. But if you
look more closely at the cover, it tells a story. In fact, it is an attempt to show what the book
is all about in one snapshot.
On the left you’ll see the sprocket holes from film. Then in the background some faint
raster lines should be evident. As you traverse to the right, the detail in the face becomes
compressed. This illustrates how an image becomes degraded and finally degenerates into
small macroblock particles that waft away in the breeze. Coming up with these illustrative
ideas is one of the most enjoyable parts of writing a book.
So there you have it. I’ve enjoyed working on this project more than any other book
that I can recall being involved with. I hope you enjoy the book too and find it helpful, as
you become a more experienced compressionist.
In closing I’d like to say that the finer points of this publication are due to the
extremely hard work by the team at Focal Press and any shortcomings you find are
entirely my fault.