CreateOutputDeviceArray

CFArrayRef CreateOutputDeviceArray()
{
    AudioObjectPropertyAddress propertyAddress = {
        kAudioHardwarePropertyDevices,
        kAudioObjectPropertyScopeGlobal,
        kAudioObjectPropertyElementMaster
    };

    UInt32 dataSize = 0;
    OSStatus status = AudioObjectGetPropertyDataSize(kAudioObjectSystemObject, &propertyAddress, 0, NULL, &dataSize);
    if(kAudioHardwareNoError != status) {
        fprintf(stderr, "AudioObjectGetPropertyDataSize (kAudioHardwarePropertyDevices) failed: %i\n", status);
        return NULL;
    }

    UInt32 deviceCount = (UInt32)(dataSize / sizeof(AudioDeviceID));

    AudioDeviceID *audioDevices = (AudioDeviceID *)malloc(dataSize);
    if(NULL == audioDevices) {
        fputs("Unable to allocate memory", stderr);
        return NULL;
    }

    status = AudioObjectGetPropertyData(kAudioObjectSystemObject, &propertyAddress, 0, NULL, &dataSize, audioDevices);
    if(kAudioHardwareNoError != status) {
        fprintf(stderr, "AudioObjectGetPropertyData (kAudioHardwarePropertyDevices) failed: %i\n", status);
        free(audioDevices), audioDevices = NULL;
        return NULL;
    }

    CFMutableArrayRef outputDeviceArray = CFArrayCreateMutable(kCFAllocatorDefault, deviceCount, &kCFTypeArrayCallBacks);
    if(NULL == outputDeviceArray) {
        fputs("CFArrayCreateMutable failed", stderr);
        free(audioDevices), audioDevices = NULL;
        return NULL;
    }

    // Iterate through all the devices and determine which are output-capable
    propertyAddress.mScope = kAudioDevicePropertyScopeOutput;
    for(UInt32 i = 0; i < deviceCount; ++i) {
        // Query device UID
        CFStringRef deviceUID = NULL;
        dataSize = sizeof(deviceUID);
        propertyAddress.mSelector = kAudioDevicePropertyDeviceUID;
        status = AudioObjectGetPropertyData(audioDevices[i], &propertyAddress, 0, NULL, &dataSize, &deviceUID);
        if(kAudioHardwareNoError != status) {
            fprintf(stderr, "AudioObjectGetPropertyData (kAudioDevicePropertyDeviceUID) failed: %i\n", status);
            continue;
        }

        // Query device name
        CFStringRef deviceName = NULL;
        dataSize = sizeof(deviceName);
        propertyAddress.mSelector = kAudioDevicePropertyDeviceNameCFString;
        status = AudioObjectGetPropertyData(audioDevices[i], &propertyAddress, 0, NULL, &dataSize, &deviceName);
        if(kAudioHardwareNoError != status) {
            fprintf(stderr, "AudioObjectGetPropertyData (kAudioDevicePropertyDeviceNameCFString) failed: %i\n", status);
            continue;
        }

        // Query device manufacturer
        CFStringRef deviceManufacturer = NULL;
        dataSize = sizeof(deviceManufacturer);
        propertyAddress.mSelector = kAudioDevicePropertyDeviceManufacturerCFString;
        status = AudioObjectGetPropertyData(audioDevices[i], &propertyAddress, 0, NULL, &dataSize, &deviceManufacturer);
        if(kAudioHardwareNoError != status) {
            fprintf(stderr, "AudioObjectGetPropertyData (kAudioDevicePropertyDeviceManufacturerCFString) failed: %i\n", status);
            continue;
        }

        // Determine if the device is an output device (it is an output device if it has output channels)
        dataSize = 0;
        propertyAddress.mSelector = kAudioDevicePropertyStreamConfiguration;
        status = AudioObjectGetPropertyDataSize(audioDevices[i], &propertyAddress, 0, NULL, &dataSize);
        if(kAudioHardwareNoError != status) {
            fprintf(stderr, "AudioObjectGetPropertyDataSize (kAudioDevicePropertyStreamConfiguration) failed: %i\n", status);
            continue;
        }

        AudioBufferList *bufferList = (AudioBufferList *)malloc(dataSize);
        if(NULL == bufferList) {
            fputs("Unable to allocate memory", stderr);
            break;
        }

        status = AudioObjectGetPropertyData(audioDevices[i], &propertyAddress, 0, NULL, &dataSize, bufferList);
        if(kAudioHardwareNoError != status || 0 == bufferList->mNumberBuffers) {
            if(kAudioHardwareNoError != status)
                fprintf(stderr, "AudioObjectGetPropertyData (kAudioDevicePropertyStreamConfiguration) failed: %i\n", status);
            free(bufferList), bufferList = NULL;
            continue;
        }

        free(bufferList), bufferList = NULL;

        // Add a dictionary for this device to the array of output devices
        CFStringRef keys    []  = { CFSTR("deviceUID"),     CFSTR("deviceName"),    CFSTR("deviceManufacturer") };
        CFStringRef values  []  = { deviceUID,              deviceName,             deviceManufacturer };

        CFDictionaryRef deviceDictionary = CFDictionaryCreate(kCFAllocatorDefault,
                                                              (const void **)keys,
                                                              (const void **)values,
                                                              3,
                                                              &kCFTypeDictionaryKeyCallBacks,
                                                              &kCFTypeDictionaryValueCallBacks);


        CFArrayAppendValue(outputDeviceArray, deviceDictionary);

        CFRelease(deviceDictionary), deviceDictionary = NULL;
    }

    free(audioDevices), audioDevices = NULL;

    // Return a non-mutable copy of the array
    CFArrayRef copy = CFArrayCreateCopy(kCFAllocatorDefault, outputDeviceArray);
    CFRelease(outputDeviceArray), outputDeviceArray = NULL;

    return copy;
}