RE: Hello again:)

Jason Williams (streak@ccwf.cc.utexas.edu)
Tue, 9 Jun 1998 03:54:24 -0500 (CDT)


On Mon, 8 Jun 1998, Heather James wrote:
> Its very strange - as I don't normally use the Audio very much in
> CU-SeeMe - but I started Cornell v1 and noticed MY audio was grayed out -
> and not selectable in Preferences.

>From what I can tell, this happens when there's other software using the
audio device (or some other application didn't close it correctly). A
reboot should fix it. I've had this happen before when other programs
crash. They don't close it and CU can't use it, so it's grayed out.

> I started ver 92 and couldn't get anything either - when I tried to get
> to the Audi Preferences, it said "Please enter an interger between 1 and
> 8".

This is because 0.92b2 and 1.0 use the same config file. In 1.0, you have
more than 8 windows selected to be open (Max Video Windows). Going BACK
to 0.92b2 requires you to lower that to 8 or less. That doesn't have
anything to do with audio though.

> Now when I open Cornell v1, then audio is normal again. My suspicion is
> that you have capabilities in WhitePine 3.1.1 that Cornell 1 doesn't, and if
> you leave it configured to one of those newer WhitePine-only audio codecs,
> Cornell can't start Audio properly.

No..the codecs are completely seperate. There are no shared audio codecs
between the White Pine versions and the Cornell version. My guess is
some other application had control of the sound card and 1.0 couldn't use
it, so it grayed it out. To test this, load up several applications which
use the sound card (sound recorder works fine). THEN load up 1.0 and I
imagine the same thing will happen.

I guess that's a little oversight that wasn't looked into much...the
ability to dynamically enable audio support after starting CU with it
disabled. Once it's loaded, it will open/close it correctly so other
sound applications work without blocking the sound card.

> Maybe the Audio Codec setting is held in the Windows registry, and
> used by any CU that is opened?

It's independent of the codec.

> Whatever it is/was, I doubt most folks would have all these versions of the
> software available/installed to use.

They shouldn't need it. The audio codecs are independent of other
releases (1.0 doesn't use a "delta-mod" codec that WP installs). It's
hardcoded into the program. The only dependent codecs are the video
codecs.

> > Needless to say, something happens on my system because my friends have
> > mentioned that they even have an Audio Tab in Preferences? I
> > dont..and all
> > other references on the toolbar, etc. are grayed-out and
> > unavailable to me?

Make sure he/she has a sound card installed. :) They also can't have any
other sound applications loaded when they load up 1.0.

Some other notes on sound...It doesn't appear the 1.0 User's Guide has
much on the sound controls. But here's what I know that may help others
trying to do sound:
If you're on a modem, I've had the best luck with:
1) Delta-Mod codec
2) Record Buffer size slider all the way to the right
3) Play Buffer size slider all the way to the right
4) PreRoll Size slider all the way to the right
5) PreRoll Threshold slider all the way to the left

As far as what the various sliders DO...I dug up some email from Steve
Edgar pertaining to audio:
"* Change record/play buffer ranges. Buffers can go from 240 - [1440]
bytes."

"* Add PreRoll Slider. "PreRoll" acts as a kind of "jitter buffer", and can
"smooth out" choppy audio under certain conditions by introducing some
delay."

"The PreRoll setting is the number of buffers that will get queued before
playout begins."

"Add "PreRoll Threshold" slider to Audio tab. This is the amount of time
that must go by for the "PreRoll" (jitter buffering) to kick in."

Not sure if that helps any, but 1.0 does seem to give you more control
over the audio. You also have to keep in mind the tradeoff between
buffered audio and the audio cutting in and out. The more buffer space
you give audio, the more delayed it is but the less broken up it is. But
it can be delayed by a few hundres milliseconds as well.

--
streak@ccwf.cc.utexas.edu    * Jason Williams -- Austin, Tx.  |     |
streak@mail.utexas.edu       * University of Texas at Austin  | ___ |
streak@cs.utexas.edu         * BS Computer Science             \_|_/
*************** http://ccwf.cc.utexas.edu/~streak/ **************|