RealVideo is the dominant streaming technology on the
web today and will play an
increasing role in broadband web delivery in
the near future. In this article we'll
see how to create video optimized for the web,
how to encode it and how to
incorporate it with SMIL.
Delivering video over the web is the Holy Grail of web
development. It's the magic bullet that will allow the web to
compete with TV as a viable entertainment medium. However
streaming video across the Internet still requires some serious
bandwidth. Let's admit it, video at 28.8 is an experiment. It's
a promise of things to come; it is not a viable technology. The
Real compression codecs keep getting better every year. Some of
the new G2 codecs make 56kbp/sec video look pretty good. I can
remember trying to get video to playback off a 1X CD-ROM back in
1993. It was usually
Quicktime compressed with Cinepak and it
was playing back at about 15 frames per second (fps) at 160x120
pixels and it was always locking up. A 1X CD-ROM gives you
800kbps or 100K/sec! I just had ADSL installed and my Internet
connection is 640kbps. Only now six years later do I have the
Internet bandwidth that I had running from CD-ROM back in 1993.
When I stream video over the Internet at these rates it is
24-30fps and usually 320x240. The difference is better
compression codecs and faster computers to decompress the video.
When RealVideo is combined with other media types such as
graphics, audio, and text it can make for a powerful multimedia
presentation. This is the environment that the
G2 Real Player
and
SMIL provide.
Broadband access to web is the key ingredient for true streaming
video. Currently there are about 1.25 million home users with
cable or ADSL service (1 million cable and 250K ADSL). In
addition to this there are 10 million users who access the web
either through a fractional T1 line or over ISDN. Unfortunately
most of these 10 million users are viewing the web at work where
entertainment viewing is discouraged. That doesn't leave all
that great a market penetration for broadband RealVideo. However,
there is a lot of lip service being paid to broadband development.
The recent merger of Yahoo and Broadcast.com should help speed
the delivery of a true broadband portal. In the mean time several
sites are already aggregating broadband video and other content.
OnBroadband.com
is a site dedicated to aggregating broadband content including
RealVideo. Another site,
BroadbandZone.com,
is dedicated to Broadband content as well as discussions of
development tools, books, and tutorials. Other sites focusing
on RealVideo and its incorporation into SMIL are
Streaming Media World
and
JustSmil.
Including RealVideo in an SMIL presentation can be quite a
challenge if you are planning on delivering at anything below
56kbps. The lowest setting for RealVideo is delivery over a
28.8 modem. This is going to produce video running at about
.25 fps or one frame every four seconds. If you use the full
bandwidth of a 56kbps modem you might get 10 fps. However,
you'll want to be able to stream other SMIL media types so the
video will probably be encoded at 28.8kbps. If you're doing
graphics this means you can download a new graphic that is 10K
every 5 seconds to give a slide show along with the video.
RealText
could also be added to the presentation since it takes
up only minimal bandwidth.
