Re: Has anyone usable QuickCam audio on a Mac fx or other Mac?

Ko s (ko@knoware.nl)
Tue, 19 Sep 1995 19:38:40 +0200


Problem located and have workaround.
Cause: localtalk load on slow cpu

>Hi, Ko. I have used the QuickCam audio on my Quadra 700 and on my IIcx.
>(It was on those machines that I did the testing of our code to support the
>QuickCam audio.) I have used in in a point-to-point connection between
>those machines and in reflector configurations. I was using 0.83xxx
>versions of CU-SeeMe and version 1.0.3 of the QuickCam extensions.
>
>Have you tried the various sound encoding choices? Some sound better than
>others, but they should all work. (This is via the "sound" pull-down menu
>that you get when you push the right-most button at the bottom of your
>local video window.)
>
>The resampling from 5231 samples per second to 8000 samples per second does
>not use floating-point arithmetic.
>
>Larry Chace (RLC1@cornell.edu)

Aaarggghh, so it can be done but I can't for now.

Yes I used the various sound encoding choices. At least 16Kb/s delta =90
should do the job, 50 or 100 ms buffer. Do you need to set them at both
sides?

<4 hours later>
After some experimenting, it seems connecting my fx (40Mhz cpu) to a
powerbook 160 (20Mhz cpu?) over localtalk (appletalk encapsulating ip) is
just to much for the whole setup.

Different setup

I connect the fx with the powerbook via direct-slip (no modem) , and Yes
=46olks I get Quickcam audio!! If I had a real IP provider all this wouldn't
be discovered ;-)

Something puzzles me though , when I did the stuff over localtalk I got a
much better video thruput. Should there too be a 150, 200 250 ms buffer for
sound encoding? Maybe localtalk hacks-up things to much but overall
bandwidth is better then the 38400 b/s I serial tested with.

BTW connecting to "Self" is it a local-loop connect , how local? It seems
to need MacTCP and outside IP ; correct?

So I have to wait to super early tomorrow-morning when global/transatlantic
bandwidth is at it's best for me (in Holland)