Re: calling audio device listener on master channel volume?
Re: calling audio device listener on master channel volume?
- Subject: Re: calling audio device listener on master channel volume?
- From: Jeff Moore <email@hidden>
- Date: Thu, 24 Aug 2006 14:58:53 -0700
Nope. You are incorrect. That system has just individual channel
volume controls and no master control. You can see this in apps like
Audio MIDI Setup or HALLab.
Pretty much the only built-in hardware that has a master volume
control are some of our more recent towers and then only when it is
using the built-in speaker. Everything else either has no volume
controls or individual channel controls.
On Aug 24, 2006, at 2:53 PM, Navyn Muhammed Rajoo wrote:
im using the kAudioHardwarePropertyDefaultSystemOutputDevice from my
g4 ibook, and im pretty sure there is a master channel there. thx
On Aug 24, 2006, at 5:14 PM, Jeff Moore wrote:
If the device in question doesn't have a master channel volume
control, then signing up to listen to changes in it's value won't
do you a lot of good.
The volume slider in the Sound Prefs figures out where the volume
controls on the device are and uses them appropriately to simulate
a master volume control when there really isn't one by adjusting
the volume controls on the individual channels.
On Aug 24, 2006, at 1:57 PM, Navyn Muhammed Rajoo wrote:
OSStatus result = AudioDeviceAddPropertyListener(_audioDevice, 0,
0, kAudioDevicePropertyVolumeScalar, callback, &clientData);
above doesn't work, but when i call add property listener on the
stereo channels Left and Right the callback function gets called
even when i adjust the master volume slider in system preference,
but the problem is the left channel changes its scalar volume
before the right, and this poses a problem to the output i wanna
achieve. Could someone tell me how i could add a volume listener
just for the master channel volume change?
OSStatus result = AudioDeviceAddPropertyListener(_audioDevice, 1,
0, property, callback, &clientData);
OSStatus result = AudioDeviceAddPropertyListener(_audioDevice, 2,
0, property, callback, &clientData);
--
Jeff Moore
Core Audio
Apple
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