I have spent a long time refactoring lots of older Swift code to compile without error in Swift 6. The app is a v3 audio unit host and audio unit. Having installed Sonoma and XCode 16 I compile the code using Swift 6 and it compiles and runs without any warnings or errors. My host will load my AU no problem. LOGIC PRO is still the ONLY audio unit host that will load native Mac V3 audio units and so I like to test my code using Logic. In Sonoma with XCode 16... My AU passes the most stringent AUVAL tests both in terminal and Logic pro. If I compile the AU source in Swift 5 Logic will see the AU, load it and run it without problems. But when I compile the AU in Swift 6 Logic sees the AU, will scan it and verify it passes the tests but will not load the AU. In XCode I see a log message that a "helper application failed to run" but the debugger never connects to the AU and I don't think Logic even gets as far as instantiating the AU. So... what is causing this? I'm stumped.. Developing AUv3 is a brain-aching maze of undocumented hurdles and I'm hoping someone might have found a solution for this one. Meanwhile I guess my only option is to continue using the Swift 5 compiler. (appending a little note just to mention that all the DSP code is written in C/C++, Swift is used mainly for the user interface and also does some offline thready work )

In our audio unit host, we're seeing the following error thrown when keypresses are dispatched to an audio unit view , does anyone know what it means and more importantly what might be causing it ? .... I can only guess that perhaps an object has been released or not retained properly somewhere but cannot find a solution. This is error message when caught in the debugger _Thread 1: "assertion failed: '<AUAudioUnitRemoteViewController: 0x600002b00c60> does not conform to AUAudioUnitViewControllerHostInterface' in -[NSRemoteView ensureClientExportedObject] on line 7080 of file /AppleInternal/Library/BuildRoots/66382bca-8bca-11ec-aade-6613bcf0e2ee/Library/Caches/com.apple.xbs/Sources/ViewBridge/NSRemoteView.m"

We have an audio app that utilises a custom internal audio unit attached to AVAudioEngine to do DSP processing. Currently: MIDI arrives at the input port for the app (created with MIDIDestinationCreateWithProtocol). For MIDI 1 we use AUScheduleMIDIEventBlock to pass the events from the midi input to the audio unit. All works well for MIDI 1. So while we ponder on it ourselves we have some questions to throw into the ether... a) For MIDI 2 there appears to be no equivalent method to AUScheduleMIDIEventBlock to send UMP to an audio unit? b) We initially chose the audio unit approach because MIDI and audio processing is all handled neatly, but is this approach essentially redundant? Would it be better to put a tap somewhere on the AVAudioEngine and pass MIDI 2 events directly from the input to the tap? I fear in that case synchronising MIDI to audio nicely would be a pain? c) perhaps we should wait until apple implement a UMP version of AUScheduleMIDIEventBlock?

Is it possible to get Thread Sanitizer to work when debugging an audio unit extension? For me XCode just waits forever after the host app is launched and before the AU debugging session starts. (Host and AU are part of the same project)

I have a situation where at any one time my AudioUnit can be represented by only a few parameters or literally many 100s.This dynamic situation is under the control of the user and the maximum number of parameters and their hierarchy cannot be predicted in advance. ( at least not accurately ).When the parameters are to change I am setting the parameterTree property by creating a new tree with the child nodes and posting KVC notifications ….. create childGroups … [self willChangeValueForKey:@"parameterTree"]; self.parameterTree = [AUParameterTree createTreeWithChildren: childGroups ]; [self didChangeValueForKey:@"parameterTree"];Most the of the app’s User Interface and AudioUnit is coded in Swift, the engine is in coded in C/C++ with an objectiveC AUAudioUnit class that acts as the go between hence the above.However there is a popular host app that crashes when I do this and it looks like the host is hanging on to the parameterTree object that’s it’s passed originally when the AU first launches but never updates it even after the KVC notifications are posted.So after that long explanation… Am I doing this correctly? OR Is there a solution that can create and rebuild a tree without making a new AUParameterTree object?If I can do that the host in question may not crash, ( although it might anyway because all the parameters have changed ).I have posted a code example to the host developer but sadly got a response which gave me the impression he was not prepared to work on a fix.Thanks!