RE: Sound Input Manager under OSX
RE: Sound Input Manager under OSX
- Subject: RE: Sound Input Manager under OSX
- From: "Tim Dorcey" <email@hidden>
- Date: Mon, 7 Jul 2003 11:34:07 -0700
Yes, we have experienced exactly the same problem. As a work-around, we
average the 2 stereo channels together. This works fine on some OSX
systems, but on others, we get a "Darth Vader" effect on the voice. It
sounds as if high frequencies are being cut out.
Not sure if the Darth Vader effect is related to the stereo averaging. The
odd thing is that on some OSX systems, the problem can be fixed by opening
the SGSettingsDialog, and toggling the Speaker (playthru) on/off. It makes
me think the different audio layers are not in sync, and this somehow syncs
it up. Unfortunately, it does not work on all OSX systems.
We are working now to port to Core Audio. Check out the "Daisy" sample code
in the Core Audio SDK. It appears to illustrate all of the ingredients
needed to record, and it does not look too difficult, though can't say we
have it working yet.
Tim
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-----Original Message-----
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From: email@hidden
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[mailto:email@hidden]On Behalf Of Mark Gilbert
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Sent: Monday, July 07, 2003 10:20 AM
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To: email@hidden
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Subject: Sound Input Manager under OSX
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Folks.
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I wonder if anyone could confirm a problem I am seeing.
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- My app was originally written in 1995, and uses the SoundInput
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Manager to record mono or stereo audio.
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We are porting it to carbon for OSX/OS9 from a single binary, and we
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are seeing some issues with the SoundInput manager behavior in OSX.
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The Carbonised app in OS9 works fine, but in OSX, we see different
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behavior for certain selectors using the SPBSetDeviceInfo and
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SPBGetDeviceInfo.
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In particular, we are NOT able to select '1 channel - mono' with the
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'chan' selector. The 'chav' returns '2' as we expect, but whereas in
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OS9, using 'chan' allows us to hence select either 1 or 2 channels to
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record, we do not see that same behavior in OSX.
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If we send 1 with the 'chan' selector, then read it back, it returns
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2 again. It wont stick on 1.
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Hence we are NOT able to select Mono recording with SPBRecord in OSX
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It would appear to be an OS Bug. I presume that the SoundInput
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manager is emulated via Core Audio under OSX, and I am guessing that
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this emulation layer is not behaving as we expect.
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It is not a practical option to port this app to Core Audio, since
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its just a very simple recorder, and 90% of our users are still on
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OS9. To support Core Audio we would need to make a dual branch
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build, which seems totally un-necessary for such a simple task which
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is supported in carbon. There are other issues such as metering, and
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auto start stop on audio threshold which would further complicate an
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attempt to support Core Audio and SoundInput manager in parallel.
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Does anyone have any further information on this ?
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Thanks
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Mark Gilbert
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--
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