Re: Aggregate question device
Re: Aggregate question device
- Subject: Re: Aggregate question device
- From: Jeff Moore <email@hidden>
- Date: Mon, 16 Nov 2009 17:21:45 -0800
Sigh. What was still wrong was a bug in the HAL (which I also wrote up) where the attributes for all the sub-devices were not getting transferred over as part of the aggregate device's creation.
To work around this bug, you will need to enable drift correction on each sub-device that needs it after you create the aggregate. You do this by getting the sub-devices of the aggregate using the property, kAudioObjectPropertyOwnedObjects. Then you set the property, kAudioSubDevicePropertyDriftCompensation, on each sub-devce as needed.
Here's some code that does just turns on the drift correction for all the sub-devices (again using PublicUtility code to make it look easy):
void TurnOnDriftCompensation(AudioObjectID inAggregateDeviceID)
{
// iterate through the sub-devices and turn on drift compensation
CAHALAudioDevice theAggregateDevice(inAggregateDeviceID);
UInt32 theNumberSubDevices = theAggregateDevice.GetNumberOwnedObjects(kAudioSubDeviceClassID);
CAAutoFree<AudioObjectID> theSubDevices(theNumberSubDevices);
theAggregateDevice.GetAllOwnedObjects(kAudioSubDeviceClassID, theNumberSubDevices, theSubDevices);
for(UInt32 theSubDeviceIndex = 0; theSubDeviceIndex < theNumberSubDevices; ++theSubDeviceIndex)
{
CAHALAudioObject theSubDevice(theSubDevices[theSubDeviceIndex]);
CAPropertyAddress theAddress(kAudioSubDevicePropertyDriftCompensation);
UInt32 theDriftCompensationValue = 1;
theSubDevice.SetPropertyData(theAddress, 0, NULL, sizeof(UInt32), &theDriftCompensationValue);
}
}
On Nov 16, 2009, at 3:44 PM, Stéphane Letz wrote:
>> That sub-device dictionary stuff was snipped out of code that builds up an aggregate device description dictionary to be passed to kAudioPlugInCreateAggregateDevice in order to create a new >aggregate device.
>
> OK so I do:
>
> CFMutableArrayRef subDevicesArrayClock = CFArrayCreateMutable(NULL, 0, &kCFTypeArrayCallBacks);
>
> CFMutableDictionaryRef subdeviceAggDeviceDict = CFDictionaryCreateMutable(NULL, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
>
> CFDictionaryAddValue(subdeviceAggDeviceDict, CFSTR(kAudioSubDeviceUIDKey), UID); <== with UID of input sub-device
> CFDictionaryAddValue(subdeviceAggDeviceDict, CFSTR(kAudioSubDeviceDriftCompensationKey), AggregateDeviceNumberRef); <== with AggregateDeviceNumberRef = CFNumberCreate of 1
> CFArrayAppendValue(subDevicesArrayClock, subdeviceAggDeviceDict);
>
> .. same for output sub-device...
>
> then in previously created aggDeviceDict:
>
> CFDictionaryAddValue(aggDeviceDict, CFSTR(kAudioAggregateDeviceSubDeviceListKey), subDevicesArrayClock);
>
> Then creating a "public" aggregate device works, but I don"t see the resampling checkboxes activated in Audio Midi Setup...
>
> What is still wrong?
--
Jeff Moore
Core Audio
Apple
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