Re: Latest Documentation?
Re: Latest Documentation?
- Subject: Re: Latest Documentation?
- From: Bill Stewart <email@hidden>
- Date: Thu, 14 Feb 2002 11:13:43 -0800
on 14/2/02 10:28 AM, Darren Gibbs wrote:
>
On Wednesday, February 13, 2002, at 01:09 PM, Jonathan Feinberg wrote:
>
>> There is some new documentation for writing Audio Device Drivers
>
>> available
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>> at:
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>> [http://developer.apple.com/techpubs/macosx/Darwin/IOKit/DeviceDrivers/Writi
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>> ngAudioDrivers/
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>> AudioOnMacOSX/The_Audio_I_on_Mac_OS_X.html]
>
>
> thanks for your reply. I am looking for documentation for users of the
>
> CoreAudio framework, not for device driver implementors.
>
>
There is actually a lot of really good info in this document on the
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low-level architecture of CoreAudio that is very applicable to users of
>
the framework, not just device driver writers. I recommend anyone
>
interested in CoreAudio have a look. It helped me _enormously_.
>
>
With all this talk of documentation, I'm curious if people can
>
articulate exactly what's missing that they _need_. Saying "I need
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useful doc" is a bit vague and doesn't help Apple figure out how to
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prioritize.
>
>
Right now there is:
>
>
a) coreaudio.pdf which covers the basics of the API
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b) the doc for driver writers which explains the low-level architecture
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c) the header files, which have extensive reference doc (blessings upon
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the CoreAudio engineers)
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d) the Daisy app which has examples of using pretty much all of
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CoreAudio's features (but which has almost no comments in the code, hint
>
hint)
I guess that I have one comment about this.
Daisy is designed to illustrate the usage of the HAL. The HAL is the lowest
part of the system and requires that you deal with a lot of the fundamental
knarliness of the devices. This can be a pain and a great distraction if
that is not your fundamental requirement. Its a nice enough looking app, but
it does a lot of work that in many cases ISN'T necessary for a developer
because we have audio units.
The Output Unit(s) (and we're looking at doing an Input Unit as well:) is a
far better service to use and there is minimal cost associated with using
them (I would say none, but someone will scream if I did:).
It deals with these device issues (and the units are maintained by us), so
we can provide a consistency in behaviour that is important for ours and
yours users.
There is an example (with 2 versions) in:
/Developer/Examples/CoreAudio/Services
Which shows two different ways of using it
(a) having it doing any format conversions required
(b) having you do some additional work, but then using the device in its
current format (and taking care of that if it changes)
I would strongly recommend these examples to anyone coming to grips with
this. (They also show usage of the AudioConverter which is a very powerful
tool for dealing with those issues)
There is also a java version of the same flavour in the Java/SDK/ directory.
>
e) this mailing list which seems pretty active
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f) some examples and doc out on the net:
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>
http://www.audiosynth.com/sinewavedemo.html
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http://www.portaudio.com/ (look for pa_mac_core)
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http://raphaelsebbe.multimania.com/MacOSX_Examples.html
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http://www.omnigroup.com/ftp/pub/software/Source/MacOSX/Games/GDC2001-PortingT
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oOSX.
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pdf
>
>
What else would help?
>
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