Re: MacPPC-Transmitting at 0.5 fps Does Not a Friend Make!

Dennis J. Streveler (strev@mobius.net)
Mon, 24 Jun 1996 09:58:01 -0700


At 02:52 PM 6/21/96 -0700, joelcal@loop.com wrote:
>Dear Mac Users:
>
>PLEASE, PLEASE, could anyone offer any words of wisdom as to how to increase
>my pitiful transmission rate of 0.0 - 2.5 fps maximum on every connection?
>People with whom I connect uniformly complain, "you're frozen", or "I'm
>getting 0.0 from you." I have a Mac PPC Performa with 24 megs, a 28.8 modem
>and a B&W Quickcam and run my transmission rate at 5 or 10 minimum and 30ish
>maximum. I use CU-SeeMe version .83b3PPC.
>
>Could the problem be with the slowness of the server? with my internet
>provider's connection? my settings?
>
>Any help at all would be beyond terrific!
>
>Thanks, thanks, thanks,
>
>Joel

Hello Joel,

Pitiful? Seriously, I wish I could have 2.5 fps on a sustained basis at
28.8. Be reasonable here. How much video information do you think you can
send over a 28.8 pipe?

A full video NTSC TV transmission, uncompressed, requires about 160Mbps to
transmit. That's MEGAbits. So do the math and figure out how much is
reasonable to send over a POTS telephone line.

Of course, many tricks are used to minimize the bandwidth needed:

1) Make the picture format smaller. CU (and most other video programs) use
160x120 pixels.

2) Compress, compress, compress!

But even with all these tricks, there is just so much information that can
be sent. The best thing you can do, is minimize the need for other bandwidth
by limiting other traffic on your line. So, ask the other person to pause
the picture at their end from time to time, DON'T use audio, etc. so that
your picture can get through.

Hope this helps.

-Dennis

--------------------------------------+------------------------------
Dennis J. Streveler, Ph.D., | Internet: strev@mobius.net
Systems Consultant | CIS: 71036,1645
| CUSeeMe: strev.mobius.net
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