Streaming Video on Your
Website - Convert Visitors into Customers
Streaming video is a
sequence of "moving images" that are sent in compressed
form over the Internet and displayed by the viewer as they arrive.
Streaming media is streaming video with sound. With streaming video
or streaming media, a Web user does not have to wait to download
a large file before seeing the video or hearing the sound. Instead,
the media is sent in a continuous stream and is played as it arrives.
The user needs a player, which is a special program that uncompresses
and sends video data to the display and audio data to speakers.
A player can be either an integral part of a browser or downloaded
from the software maker's Web site.
Major streaming video
and streaming media technologies include RealSystem G2 from RealNetwork,
Microsoft Windows Media Technologies (including its NetShow Services
and Theater Server), and VDO. Microsoft's approach uses the standard
MPEG compression algorithm for video. The other approaches use proprietary
algorithms. (The program that does the compression and decompression
is sometimes called the codec.) Microsoft's technology offers streaming
audio at up to 96 Kbps and streaming video at up to 8 Mbps (for
the NetShow Theater Server). However, for most Web users, the streaming
video will be limited to the data rates of the connection (for example,
up to 128 Kbps with an ISDN connection). Microsoft's streaming media
files are in its Advanced Streaming Format (ASF).
Streaming video is usually
sent from prerecorded video files, but can be distributed as part
of a live broadcast "feed." In a live broadcast, the video
signal is converted into a compressed digital signal and transmitted
from a special Web server that is able to do multicast, sending
the same file to multiple users at the same time.
Streaming media is audio
and video that are transmitted on the Internet in a streaming or
continuous fashion, using data packets. The most effective reception
of streaming media requires some form of broadband technology such
as cable modem or DSL. A packet is the unit of data that is routed
between an origin and a destination on the Internet or any other
packet-switched network. When any file (e-mail message, HTML file,
Graphics Interchange Format file, URL - Uniform Recourse Locater
request, and so forth) is sent from one place to another on the
Internet, the Transmission Control Protocol (TCP) layer of TCP/IP
divides the file into "chunks" of an efficient size for
routing. Each of these packets is separately numbered and includes
the Internet address of the destination. The individual packets
for a given file may travel different routes through the Internet.
When they have all arrived, they are reassembled into the original
file (by the TCP layer at the receiving end).
A packet-switching scheme
is an efficient way to handle transmissions on a connectionless
network such as the Internet. An alternative scheme, circuit-switched,
is used for networks allocated for voice connections. In circuit-switching,
lines in the network are shared among many users as with packet-switching,
but each connection requires the dedication of a particular path
for the duration of the connection. "Packet" and "datagram"
are similar in meaning. A protocol similar to TCP, the User Datagram
Protocol (UDP) uses the term datagram.
MPEG, the Moving Picture
Experts Group, develops standards for digital video and digital
audio compression. It operates under the auspices of the International
Organization for Standardization (ISO). The MPEG standards are an
evolving series, each designed for a different purpose. To use MPEG
video files, you need a personal computer with sufficient processor
speed, internal memory, and hard disk space to handle and play the
typically large MPEG file (which has a file name suffix of .mpg).
You also need an MPEG viewer or client software that plays MPEG
files. (Note that .mp3 file suffixes indicate MP3 (MPEG-1 audio
layer-3) files, not MPEG-3 standard files.) You can download shareware
or commercial MPEG players from a number of sites on the Web.
The term codec is an
acronym that stands for "compression/decompression." A
codec is an algorithm, or specialized computer program, that reduces
the number of bytes consumed by large files and programs. In order
to minimize the amount of storage space required for a complicated
file, such as a video, compression is used. Compression works by
eliminating redundancies in data. Compression can be done for any
kind of file, including text, programs, images, audio, video, and
virtual reality (VR). Compression can reduce the size of a file
by a factor of 100 or more in some cases. For example, a 15-megabyte
video might be reduced to 150 kilobytes. The uncompressed file would
be far too large to download from the Web in a reasonable length
of time, but the compressed file could usually be downloaded in
a few seconds. For viewing, a decompression algorithm, which "undoes"
the compression, would have to be used.
There are numerous standard
codec schemes. Some are used mainly to minimize file transfer time,
and are employed on the Internet. Others are intended to maximize
the data that can be stored in a given amount of disk space, or
on a CD-ROM. Codec’s are used in many popular Internet products,
including QuickTime, Netmeeting, Cu-Seeme, and VDOphone.
Flash, is a popular authoring
software developed by Macromedia, and is used to create vector graphics-based
animation programs with full-screen navigation interfaces, graphic
illustrations, and simple interactivity in an antialiased, resizable
file format that is small enough to stream across a normal modem
connection. The software is ubiquitous on the Web, both because
of its speed (vector-based animations, which can adapt to different
display sizes and resolutions, play as they download) and for the
smooth way it renders graphics. Flash files, unlike animated but
rasterized GIF and JPEG, are compact, efficient, and designed for
optimized delivery. Known as a do-it-yourself animation package,
Flash 4 gives Web designers the ability to import artwork using
whatever bitmap or illustration tool they prefer, and to create
animation and special effects, and add sound and interactivity.
The content is then saved as file with a .SWF file name extension.
Web users with Intel
Pentium or Power Macintosh processors can download Flash Player
to view Flash content, which performs across multiple browsers and
platforms. Flash is lauded for being one of the Web's most accessible
plug-in. According to an independent study cited by Macromedia,
over 90 percent of Web users already have Flash Player installed.
Macromedia was recently acquired by Adobe in a 3.4 billion dollar
deal.
About the Author: Ole
Arndt is President of Global Media LLC, in Branchburg NJ.