Message: 8
Date: Thu, 05 Nov 2009 09:24:08 -0800
From: Jeff Moore <email@hidden>
Subject: Re: Built-In devices on single thread
To: CoreAudio API <email@hidden>
Message-ID: <email@hidden>
Content-Type: text/plain; charset=us-ascii; format=flowed; delsp=yes
The solution it seems like you are looking for is to create an
aggregate device that has all the built-in devices in it. There has
been a lot of discussion about using aggregate devices on this list
previously.
On Nov 5, 2009, at 8:02 AM, audioboy 77 wrote:
In my application (a pro-audio effect unit/synthesizer), I want to
show the Built-In devices as one physical device, with different
channels representing the Microphone, Input and Output.
To do this, I use the "related devices" property to find all
subdevices and group them together.
I then tried starting an IOProc on the first subdevice (which is the
microphone on my system) with the idea that I would read/write the
buffers for all the sub-devices in that callback. However, im
getting mData which is always NULL. Im not sure if this is
expected, but im not sure how to create the buffer. (There is a
property to set the buffersize, but no property to get or set the
address).
I also tried another approach. I registered each sub-device with
the same callback, hoping that the register proc might cause the
buffers to get created. When doing this, I have discovered that
each subdevice is running on a seperate thread. This is strange
given they should be on the same clock, and seems wrong given that I
want the latency to be as low as possible.
I've been messing around with this on and off for a couple weeks
now, and have basically run out of ideas. Could somebody please
explain the correct strategy on how to approach this?
--
Jeff Moore
Core Audio
Apple
