CODEWITHSUNDEEP
macosaudiobluetoothcore-audioaudiounit
spartygw
spartygw

Reputation: 3452

OSX CoreAudio query for bluetooth device manufacturer returns NULL - is there any way for me to then reference this device for AudioComponentFindNext?

I am querying all active input devices in osx and then try to use AudioUnit for playing audio through the bluetooth device (if connected).

I have a bluetooth device that returns a UID and device name but fails to return a device manufacturer (kAudioObjectPropertyManufacturer).

In reading Apple docs I see The unique vendor identifier, registered with Apple, for the audio component so I must assume that the vendor didn't bother registering with Apple.

Without the manufacturer I am not sure how to select the device. The code I inherited enables audio like this:

AudioComponentDescription desc;
desc.componentType = kAudioUnitType_Output;
desc.componentSubType = kAudioUnitSubType_VoiceProcessingIO; // 'vpio'
desc.componentManufacturer = manufacturerName;
desc.componentFlags = 0;
desc.componentFlagsMask = 0;

AudioComponent comp = AudioComponentFindNext(NULL, &desc);
OSStatus error = AudioComponentInstanceNew(comp, &myAudioUnit);

Is there a way to create an AudioUnit without a device manufacturer? Or better yet, is there a way to create an AudioUnit using whatever the current input/output audio device is set to?

Upvotes: 1

Views: 361

Answers (1)

sbooth
sbooth

Reputation: 16976

If you have a device's UID you can translate it into a device ID:

// deviceUID is a CFStringRef

AudioDeviceID deviceID = kAudioDeviceUnknown;

AudioObjectPropertyAddress propertyAddress = {
    .mSelector  = kAudioHardwarePropertyDeviceForUID,
    .mScope     = kAudioObjectPropertyScopeGlobal,
    .mElement   = kAudioObjectPropertyElementMaster
};

AudioValueTranslation translation = {
    &deviceUID, sizeof(deviceUID),
    &deviceID, sizeof(deviceID)
};

UInt32 specifierSize = sizeof(translation);

auto result = AudioObjectGetPropertyData(kAudioObjectSystemObject, &propertyAddress, 0, nullptr, &specifierSize, &translation);
if(kAudioHardwareNoError != result) {
    // Handle error
}

if(kAudioDeviceUnknown == deviceID)
    // The device isn't connected or doesn't exist

And from there you can set the AU's kAudioOutputUnitProperty_CurrentDevice with deviceID.

Upvotes: 1

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