Video + audio = teleconferencing

Dennis J. Streveler (
Sat, 11 May 1996 11:17:26 -0700

At 11:44 AM 5/11/96 -0500, you wrote:
>>At 05:00 PM 5/8/96 -0400, you wrote:
>>>I am a new user to CU-SEEME. I recently attended a conference that
>>>demonstrated CU-SEEME over a 100MB/sec ethernet connection. I was
>>>very impressed.
>>>Now for my situation, I am testing CU-SEEME over a 10MB/sec ethernet
>>>LAN. I have two PC's connecting to each other over this LAN. The video
>>>is acceptable (4-10 fps) but the audio is terrible. If I freeze video then
>>>the audio is acceptable. What can I expect over a 10mb/sec connection?
>>>I have read a lot of messages that deal with a 28.8 modem and it is my
>>>impression that we should be getting a better response from our PC's.
>>>PS. is there a way to limit the number of frames per second? I tried to
>>>use the local video window but it did not work. When I increased the
>>>Max KBS I noticed an increase in frames transmitted and little effect on
>>Yes my observations are similar. At 10Base-T speed the audio is still a
>>severe problem in CU. I am glad to hear that at 100Base-T that the audio
>>impressed you. That is encouraging.
>>I really don't think you should have to freeze video on a 10meg connection
>>to get decent audio. Are you using Enhanced CU? I am told that there are
>>improvements there, but, frankly, I have no direct evidence of this (I've
>>used both the Cornell and White Pine version). In general audio has been a
>>disaster. I sat at the end of a T1-T1-ISDN conference (at the ISDN end!) the
>>other day and we had to revert to Internet Phone to get our audio up to an
>>acceptable level.
>>I trust White Pine will address the audio problem real-soon-now. With the
>>emergeance of telephony products such as Internet Phone and Web Talk,
>>people's expectations of audio quality has increased markedly of late.
>If you are on an ethernet network and are connecting to someone else on the
>same segment, you should try adjusting your settings up to about 300k
>receive max and 80k transmit max. At this higher speed, you could use the
>32k audio codec and possibly get much better results. Also keep in mind
>that the speed of the CPU and the type of sound card could be a contributing
>factor in the poor audio quality.
>As far as the video goes, on ethernet to ethernet connections, you should be
>able to get up to 30 frames per second EASILY. I have actually done this at
>my office. I could watch the other guy typing, and could almost READ his
>chat that way, in addition to seeing the text in the chat window. These
>speeds would be perfect even for fast fingerspelling (sign language).
>Bill Woodland (
>Squeek on Undernet IRC
>Channel Manager #CU-SeeMe
>PC only, no MAC questions, please.


I've tried every conceivable setting, and yes by tinkering you can improve
the throughput, or at least tune it to the situation that presently exists.
I would really like to see CU be (more) adaptive to network conditions as
you really don't have time, especially during a conference (what happens if
somebody else jumps onto the same ethernet segment in the middle of a
teleconference and starts using gobs of bandwidth for another purpose?)

And conspicuously absent in your description above is real consideration of
audio. I don't know, but for me, video + typing /= teleconferencing.
Reasonable video + reasonable audio = teleconferencing. The chat window can
be used to nicely augment the audio by spelling out ambiguous terms (like
email addresses or whatever) but normal conversation should be able to be
accomplished through the audio codecs, in my opinion. Otherwise you are
limited to gawkers, experimenters, voyeurs, and other "entertainment" uses.
It is my proposal that systems like CU should (and could!) be adapted to do
real work, as low-cost desktop conferencing tools at relatively low
bandwidths, as well as be entertaining.

I've used CU to help do project management for software development projects
in five countries, and I am very excited about the prospects of such systems
in helping creating an ongoing sense of "community" between developers
working on the same project in different locations. In fact I would say that
CU has been indispensible in my efforts to date. That's what just makes me
so thirsty for more!


Dennis J. Streveler, Ph.D., | Internet:
Systems Consultant | CIS: 71036,1645
| CUSeeMe:
"Future Technologies in Medicine" +------------------------------
"International Software Development | 415 239-1441
Methodologies" | 415 469-9476 fax
"Human-Computer Interface Design +------------------------------
for Casual Users" | 127 Lake Merced Hill
| San Francisco CA 94132 USA

My job? To send the appropriate electrons hurtling around the globe.