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What
Is Downloading?
Downloading refers to the actual transferring of a document or file from
the Internet to your own computer. Most files are downloaded
in a compressed
format and when they are uncompressed they will explode into many other
files. Compressing files has many benefits. By compressing files you
can store many files into one, or make a big file smaller so it is quicker
to download. What is really nice is all files can be
compressed including all your sounds, movies, and
the programs to
run
them. Once the files are downloaded, they will need to be decompressed.
For Zip
and Hqx files you will need other programs to decompress/unzip/expand
them. For PC users winzip is
the most popular and for Mac users stuffit
expander.
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How
is Downloading Affected by Size?
The
size of your Web pages can play an important role in your site's
success. Simple things like using images sparingly, putting text
in html whenever possible, and limiting the size of video files,
will make your Web pages download a lot faster.
The 50 KB rule
One idea is to plan your Web pages with a specific size maximum. If the Web
pages you make are far too heavy and take ages to load on a regular PC, with
a regular modem connection, you may lose impatient viewers. Don't forget that,
despite
the popularity of broadband, a lot of people
still use analogue modems. You should also not forget problems with overloaded,
slow company networks that may lengthen the time even further. Keep in mind that
the average user gets slightly annoyed after ten seconds of waiting and genuinely
considers doing something else after twenty seconds of waiting, it is best to
limit the page size to 50 KB. This size limit is particularly important for your
homepage. Your homepage is the user's first contact with your Web site and if
that doesn't go well, chances are the user won't even bother to look at the other
pages of your site. The 50 KB size limit is important for all pages of your site
however. A page of 50 KB takes about ten to fifteen seconds to load via a regular
modem connection and most users aren't willing to wait much longer. In addition,
Cable modem speeds vary between 64 Kb per seconds & 2 Mb per second depending
on service when downloading. |
A
File Download Time Calculator
Click on the link below to access a Web page that is part of the Martindale's-The
Reference Desk Web pages. The calculator can determine the approximate time
it will take to transmit Kb or Mb.
www-sci.lib.uci.edu/HSG/AATimeCalc.html |
Downloading
Video and Audio Files
A number of different multimedia formats can be used for down loading. These
need to be installed or downloaded before the video can be seen or the audio
heard. The following are some of the more common formats used:
Windows Media (.avi)
A Microsoft Windows Media Player® is needed to view some videos.
To download and install the software go to Microsoft
Download Center. If the video is an .avi file, this is not a “streaming” format,
i.e. the viewer must download the complete file before it will start to play.
RealMedia (.rm)
This is a streaming format which will start playing before being completely
downloaded. RealPlayer is needed to view
these files.
MPEG (.mpg)
MPEG (pronounced M-peg), which stands for Moving Picture Experts
Group, is the name of family of standards used for coding audio-visual
information (e.g.,
movies, video, music) in a digital compressed format. MPEG files can be played
on Microsoft Windows Media Player® (see above) and QuickTime Player® (see
below).
QuickTime Movie (.mov)
Apple's technology for handling video,and audio. Requires QuickTime
Player®,
available free from Apple.
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Tip: For
examples for movie size downloads go to the Apple Web
site to view various movie trailers. From here you
will note a difference in video screen sizes
and downloading times:
http://www.apple.com/trailers/
Or
check out some of the videos created rin the
ETEC
Department at the University of Hawaii: http://www.hawaii.edu/etec/vr/video.htm
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