From: johnsd2@vccsouth07.its.rpi.edu (Daniel Norman Johnson)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Sound Manager Phooey!
Keywords: Sound Manager, Spanish Inquisition
Date: 5 Oct 92 15:34:34 GMT
Reply-To: johnsd2@rpi.edu
Organization: Rensselaer Polytechnic Institute, Troy, NY.

In article <1992Oct5.022712.3448@news.cs.brandeis.edu>, dan@chaos.cs.brandeis.edu (Dan Schwarz) writes:
|> In article <w=mz_wc@rpi.edu> johnsd2@rpi.edu writes:
|> >I am having a problem with an extension I am writing. This extension
|> >is really a background app (type='appe'), which plays sounds asynchronously
|> >in the background (which sounds are specified with annother program, that
|> >works);
|> ...
|> >This strange freeze happens on a friends LC whenever
|> >the sound is played, even  from an APPL. (but only if its
|> >asynchronously)
|> 
|> Speaking as a programmer who has done some SERIOUS sound manager hacking,
|> I can sympathize with your frustration. Here's what I can tell you:
|> 
|> * the Mac LC uses a crippled version of the Apple Sound Chip. So does the LC II
|> and Classic II, by the way. Major difference is that this chip can only handle
|> monophonic sound output, and cannot support simultaneous sound recording &
|> playback.

Im just using SndPlay(blah,blah,True); to do this; It should be monophonic
and (for these sounds) just ordinary sampled sound. I think.

|> * the System 6.0.7 and 6.0.6 sound managers have MAJOR bugs, especially when
|> dealing with the LC. These systems' sound input managers were taken directly
|> from alpha versions of System 7.0 (in the rush to ship the first LC and IIsi 
|> units.) Don't trust the Gestalt values they return, for example.

I don't. I dont even call Gestalt, and I dont use sound Input. Could you
be a little more specific about the bugs, that is any bugs that might
louse up asynchronous sound playback?

|> * Use 7.0 or later versions, but this won't solve all your problems. I am 
|> convinced that there are hardware or software bugs in Apple's handling of
|> this particular sound chip. For example, play back a QuickTime movie with
|> sound (in SimplePlayer or any similar product.) Switch out of the layer
|> into a product which does sound recording or otherwise uses the sound manager.
|> Switch back. Odds are, the sound will be silenced upon returning to the QT
|> movie. I don't know how to solve this problem.

Bleah. No, make that Double-bleah.

|> Unless the "delay" tactic mentioned earlier is successful, the only thing
|> you can do is to complain to MacDTS until you get a reasonable response.
|> They're not very forthcoming about Mac sound internals, but be specific with
|> your problem and maybe you can get a workaround.

Ill try to boost the delay, but it already has some delay in it- specificly
it calls WaitNextEvent so it cant start the next sound until that comes
back (which should be good for a few ticks, anyway.) So I dont know about
that. (I cant do it right now, cuz my roommates asleep. :( )

In any case, the latest version of it always closes the sound channel and opens
it again before each sound. This has teh spiffy effect that it can now
plays sounds after the Spanish Inquisition (but that does not play). So its
getting better. No progress on teh autodoubler problem tho.

-- 
			- Dan Johnson
And God said "Jeeze, this is dull"... and it *WAS* dull. Genesis 0:0

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