Date: Wed, 7 Jun 2006 17:05:15 -0700
From: Jeff Moore <email@hidden>
Subject: Re: AudioDeviceAddPropertyListener & custom controls
To: CoreAudio API <email@hidden>
Message-ID: <email@hidden">email@hidden>
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
Your HAL plug-in has to translate the IOAudioControl into a set of
properties that can be queried through the HAL's API. Once you do
that, clients listen for the changes to the control just like they
would for volume or mute.
In general, I'd advise you to implement the a similar set of
properties as what the HAL provides for a control that behaves more
or less the same. For instance, if you are implementing properties
for a custom IOAudioLevelControl subclass, you should implement
properties that cover the scalar and dB values, the dB range, and
converting between dB and scalar.