CU-SeeMe - Does Audio work on a Modem?

Gary Dietz (gdietz@wpine.com)
Tue, 06 Jan 1998 11:33:02 -0500


All,

I've heard (and personally experienced) differing levels of audio quality
using White Pine's CU-SeeMe. Techno-geeks can feel free to chime in with
more details.

First, let me say that with this environment: Pent 166, 32Mb RAM, 33.6
modem, my local ISP (Empire.Net), and CU-SeeMe 3.1 (released version) I've
achieved phone voice quality point-to-point calls on a regular basis using
the new G.723 audio codec.

On a MeetingPoint server (non-public) where the users were under my
control, and all of the audio and bandwidth settings were correct, I've
achieved the same results in a group conference (when people weren't
talking at the same time).

So why the mixed results? Why the irritating choppiness?

Well, last night, I was at work (on our Lan/T1) and called my Mom on CU 3.1
through her AOL account. She has a Pent 100, 24Mb of RAM, and AOL and a
33.6 modem. The audio REALLY sucked. (But I was getting her MJPEG video
okay--though slowly.) Why?

Well, at 8:00PM EST, she dialed into AOL and got a "24KBPS" connection.
Also, from my POV, her statistics showed a 70% packet loss and an actual
throughput of only *9*Kbps. It was a wonder we could even see each other!

So, *when* will you have good results with audio? Here are some lessons
I've learned... Feel free to chime in:

a. Just because you have a 33.6 modem doesn't mean you have a 33.6 connection

b. Your send a receive settings must be set correctly. See the
documentation or the White Pine Support pages.

c. Don't expect to open 12 video windows, a whiteboard, and get audio on a
33.6 connection. It ain't gonna happen! Or, if it does, it will be very
slow.

d. AOL and other ISPs are often oversubscribed for evening hours and it is
very hard to get enough bandwidth for even minimum requirements for
Internet Conferencing.

e. Remember that to use the new G.723 low-bandwidth audio compression, you
need at least a P100 if not faster. A 486 won't cut the newer multimedia
stuff like G.723 audio and H.263 video.

f. On a "public" server, you never know who is sending what or how they are
sending it. If you run (or rent time) on a private server, you'll usually
have better group conferencing results. And, with security and parental
control needs, it is much better to purhcase your own server, or go to
Powerscourt to rent time on a server.

g. YOUR MIC MATTERS! I went from a cheapo microphone to just a $30 mic and
the sound quality IMPROVED DRAMATICALLY, especially my ability to control
levels.

h. Audio levels can be set in a whole bunch of ways in Windows 95, even
BEFORE you take CU-SeeMe into consideration. Before starting CU, make sure
the audio input for your mic and the playback levels are set correctly on
your system.

If your audio input levels are not set correctly in Windows, your CU-SeeMe
settings won't matter much.

i. Finally, CU-SeeMe 3.1 has improved audio subsystems, and you'll get even
better results even if you just use the Voxware codec.

Positive comments invited.

Warm regards,

Gary

--
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  Gary Dietz, Product Manager, Vertical Solutions 
  White Pine Software Incorporated
  542 Amherst Street, Nashua, NH 03063
  603-886-9050 x356  gdietz@wpine.com    
Distance Learning Resource Center   http://www.wpine.com/edu/DLRC.html 
CU-SeeMe(R) Videoconferencing       http://www.cuseeme.com
MeetingPoint(tm) Conference Server  http://www.wpine.com/mp 
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