| Hello,
I'm working with audio devices that have multiple streams, and I've noticed an inconsistency when I try to get the device name and stream names as displayed in Audio MIDI Setup.
For the first example, if I want to get the name of the overall audio device, I would use the following code:
stat = AudioDeviceGetPropertyInfo(deviceID, 0, 1, kAudioObjectPropertyName, &size, NULL); if (!stat) { stat = AudioDeviceGetProperty(deviceID, 0, 1, kAudioObjectPropertyName, &size, &srDeviceName); if (!stat) CFStringGetCStringPtr(srDeviceName, kCFStringEncodingMacRoman); }
However, the above code is completely ineffective when trying to get the name of a stream. In the second example, to get the name of a stream, I found that I must use the following code:
aopa.mSelector = kAudioObjectPropertyName; aopa.mScope = kAudioObjectPropertyScopeGlobal; aopa.mElement = kAudioObjectPropertyElementMaster; stat = AudioObjectGetPropertyDataSize(streamID, &aopa, 0, NULL, &size); if (!stat) { stat = AudioObjectGetPropertyData(streamID, &aopa, size, NULL, &size, &srStreamName); if (!stat) CFStringGetCStringPtr(srStreamName, kCFStringEncodingMacRoman); }
Is there any reason why AudioDeviceGetProperty is sufficient for getting the device name but not the stream name? I tried various different values for inChannel, assuming that would be how to select the stream within a device, and I also tried supplying the streamID instead of the deviceID, but nothing worked. Is there any reason why AudioObjectGetPropertyData is required to get the stream name? It seems like the shortcut API for one name should work for the other as well.
I'm working with CoreAudio 1.4.3 on Tiger 10.4.11 (since Leopard is still not stable). I thought of trying this again on Leopard, but I did not save examples of every code variation that I tried. I'm hoping it's something simple...
Brian Willoughby Sound Consulting
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