Linkers Try Receiving a Remote Presentation?

[Tom Worthington]

I wrote Fri, 14 Aug 1998 08:05:21 +1000:

>...Do any Linkers have experience at using Netmeeting for presentations?
>...As discussed on Link some time ago, in theory web based presentations
>should work well on a low bandwidth connection, with sound and a postage
> stamp size picture of the presenter in the corner...

Since then I have had two short sessions (about 30 minutes) using Microsoft
Netmeeting (v2.1), with a small (cheap) monochrome video camera on my
sub-notebook computer (the whole set-up fits in my briefcase).

SETUP

One caller experienced considerable problems setting up Netmeeting with
Windows'98, with the PC locking up several times. However, once installed,
it appears to work okay.

Making a call was straightforward. In the first case I copied the other
person's e-mail address to the call field and was connected. In the other
they picked my name from Microsoft's directory service. During the second
call two other people tried to join in via the directory, but as Netmeeting
does not support multi-party calls, this was declined.

VIDEO

In both cases the video was only one way (from me) and was set to the
smallest size. The receiver reported a good quality picture. There is no
lip-sync, but this isn't needed in this application.

AUDIO

The sound was comparable to that on a digital mobile telephone. There was
about a two second transmission delay. This required half duplex style
handshaking to be used (one person speaking at a time and pausing before
replying), even though the connection was full duplex.

There were interruptions to speech when a large bit-map image was
transmitted (during the use of application sharing).

Full duplex caused feedback problems with callers using hands free. Whatever
said was echoed back to with a four second delay, making speech difficult.
This was solved by using an earphone. I used a combined earphone-microphone
from a mobile telephone hands free kit, which worked well and was
unobtrusive. For a group presentation, the organizer could use half duplex,
while the presenter used an earphone and full duplex..

CHAT

The text chat window worked well. This allows short messages to be sent when
there are audio problems. It would be useful for private communication
between a presenter and a remote organizer, during a group presentation.

WHITE BOARD

The white board worked, but seems of little practical value in this application.

APPLICATION SHARING

Application sharing worked, but was too slow to be of practical value and
caused audio problems.  Both a web browser and a Power point application
were used in shared mode.

The shared application works by sending a bit map image of a selected
application and the coordinates of the cursor. Presumably transmitting the
large image uses up available bandwidth and interferes with audio transmission.

It took several seconds to paint the screen at the remote end. During this
time the audio would break up. The remote user has no control over the size
or location of the shared widow on their screen. At the sending end any
window placed over the transmitted window blocks part of the view.

Text based web pages provided the best response. However, problems were
experienced in retrieving web pages from a remote server while at the same
time sharing the application. Locally stored web pages were better. Full
page images were very slow. Power point presentations were slightly faster.

If used for a group presentation, the video image could be cropped to show
just the shared presentation and video image to the audience. The presenter
and organizer could used the rest of the screen for housekeeping and private
chat communication.

OVERALL

Audio and video worked remarkably well on a dial-up connection. If you have
an Internet connection operating anyway, then you could use Netmeeting as a
low cost video phone.

Application sharing is remarkable that it works at all, but is not usable at
dial-up speeds. What is needed are specialized shared applications, such as
web browsers and presentation programs, which do not need to transmit a bit
map of the whole screen. The white board application is an example of this:
it just transmits a set of small codes to indicate what geometric shape
should be drawn on the remote screen.

For video conferencing product evaluations, including Netmeeting, see
NASA's: http://zeus.arc.nasa.gov/prod_eval_overview.html


Tom Worthington	           http://www.acslink.net.au/~tomw   PO Box 13
Immediate Past President     tomw@acslink.net.au    Belconnen ACT 2617
Australian Computer Society
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DAMA'98, 23 Oct, Canberra: http://www.acslink.net.au/~tomw/intrnt.htm