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Re: setting Input property for USB headsets
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Re: setting Input property for USB headsets


  • Subject: Re: setting Input property for USB headsets
  • From: Jeff Moore <email@hidden>
  • Date: Wed, 28 Mar 2007 17:47:53 -0700

It is definitely the case that there are devices out there (including USB headsets) that have no volume controls.

Checking for kAudioHardwareUnknownPropertyError getting returned from AudioDeviceGetPropertyInfo() or calling AudioObjectHasProperty() are fine ways to find out if the device supports a volume control on a given channel.


On Mar 28, 2007, at 4:05 PM, Neal Sidhwaney wrote:

With two different USB microphones we’ve tried, we’re getting ‘who?’ when setting kAudioDevicePropertyVolumeScalar with the following lines of code:

theStatus = AudioDeviceGetPropertyInfo (
_inputDeviceID, i, true,
kAudioDevicePropertyVolumeScalar,
NULL, &isWritable );


if(theStatus != kAudioHardwareNoError)
{
LOG(TR_ERROR, " SetMicLevel() AudioDeviceGetPropertyInfo error: %4.4s", (char*)&theStatus);
}


My question is, do USB headsets generally not support setting an input level through Core Audio? Is it a hardware deficiency or a driver problem? Is checking for ‘who?’ in this case the best way to determine if this functionality is present?


--

Jeff Moore
Core Audio
Apple




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References: 
 >setting Input property for USB headsets (From: "Neal Sidhwaney" <email@hidden>)

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