macos - 如何让音频设备 UID 传入 NSSound 的 setPlaybackDeviceIdentifier :

Question

如何让音频设备 UID(USB 扬声器)传入 NSSound 的 setPlaybackDeviceIdentifier: 方法

谢谢

Answer 1

为避免不推荐使用的 AudioHardwareGetProperty 和 AudioDeviceGetProperty 调用将它们替换为以下内容:

AudioObjectPropertyAddress  propertyAddress;
AudioObjectID               *deviceIDs;
UInt32                      propertySize;
NSInteger                   numDevices;

propertyAddress.mSelector = kAudioHardwarePropertyDevices;
propertyAddress.mScope = kAudioObjectPropertyScopeGlobal;
propertyAddress.mElement = kAudioObjectPropertyElementMaster;
if (AudioObjectGetPropertyDataSize(kAudioObjectSystemObject, &propertyAddress, 0, NULL, &propertySize) == noErr) {
    numDevices = propertySize / sizeof(AudioDeviceID);
    deviceIDs = (AudioDeviceID *)calloc(numDevices, sizeof(AudioDeviceID));

    if (AudioObjectGetPropertyData(kAudioObjectSystemObject, &propertyAddress, 0, NULL, &propertySize, deviceIDs) == noErr) {
        AudioObjectPropertyAddress      deviceAddress;
        char                            deviceName[64];
        char                            manufacturerName[64];

        for (NSInteger idx=0; idx<numDevices; idx++) {
            propertySize = sizeof(deviceName);
            deviceAddress.mSelector = kAudioDevicePropertyDeviceName;
            deviceAddress.mScope = kAudioObjectPropertyScopeGlobal;
            deviceAddress.mElement = kAudioObjectPropertyElementMaster;
            if (AudioObjectGetPropertyData(deviceIDs[idx], &deviceAddress, 0, NULL, &propertySize, deviceName) == noErr) {
                propertySize = sizeof(manufacturerName);
                deviceAddress.mSelector = kAudioDevicePropertyDeviceManufacturer;
                deviceAddress.mScope = kAudioObjectPropertyScopeGlobal;
                deviceAddress.mElement = kAudioObjectPropertyElementMaster;
                if (AudioObjectGetPropertyData(deviceIDs[idx], &deviceAddress, 0, NULL, &propertySize, manufacturerName) == noErr) {
                    CFStringRef     uidString;

                    propertySize = sizeof(uidString);
                    deviceAddress.mSelector = kAudioDevicePropertyDeviceUID;
                    deviceAddress.mScope = kAudioObjectPropertyScopeGlobal;
                    deviceAddress.mElement = kAudioObjectPropertyElementMaster;
                    if (AudioObjectGetPropertyData(deviceIDs[idx], &deviceAddress, 0, NULL, &propertySize, &uidString) == noErr) {
                        NSLog(@"device %s by %s id %@", deviceName, manufacturerName, uidString);

                        CFRelease(uidString);
                    }
                }
            }
        }
    }

    free(deviceIDs);
}