Apple

On Sep 10, 2010, at 7:02 PM, Kevin Vanwulpen wrote:

The mElement of the AudioObjectPropertyAddress (combined with scope actually) determines this. Remember
kAudioObjectPropertyElementMaster==0
(0UL in AudioHardware.h)

and channel 1 would require mElement==1 and so forth (so it's 1-indexed , so watch those for loops ;-) )

In fact I would say scopeGlobal and ElementMaster ...what does that mean?
Maybe there is some device out there with some sort of "global" volume control affecting both input and output levels.
I'd need to try it and if you're unlucky it may work on the output (I mean unlucky as I personally hate things working when they are not supposed to more than the other way around).

My 'guess' is you likely want outputscope and ElementMaster (the main-out volume control)
or a per-channel (output scope) level.

It's entirely possibly you're talking about input as well (but am guessing you're not).

I am in fact talking about input. I thank you for your guidance in this: It makes a lot of sense.

If I might reflect back your advice, taking the "input" part into account, my replacement code becomes:

Boolean settable;

AudioObjectPropertyAddress theAddress = { kAudioDevicePropertyVolumeScalar,

kAudioObjectPropertyScopeInput,

inChannel };

OSStatus status = AudioObjectIsPropertySettable(device, &theAddress, &settable);

Does this look correct?

(For bystanders, I am replacing this line of code, now deprecated:

status = AudioDeviceGetPropertyInfo(device, inChannel, true, kAudioDevicePropertyVolumeScalar, NULL, &isWritable);

)

Thanks for you help.

Peace,

Bob

Animals are not brethren, they are not underlings.

They are other nations, caught with ourselves in the net of life and time.

-Henry Beston - The Outermost House

References:
	>What became of the deprecated functions' channel parameters? (From: Bob Stuller <email@hidden>)
	>Re: What became of the deprecated functions' channel parameters? (From: Kevin Vanwulpen <email@hidden>)