I am trying to build a project that will allow me to use an iphone USB connected to a Mac as an audio output device. There are options to do this wirelessly like "AirFoil" but they all introduce latency during playback. When connected via USB, the iphone will appear in Audio Midi Setup as a device. Currently it is only selectable as an input device. I believe it can be used as an external microphone or a midi input device. My hope is that through code, the grayed output selection could be overridden. Is this even possible? From what I've read the AVAudioEngine might provide a solution to this? I have read through posts about listing all available AudioDevices by ID. Listing all available audio devices From here would I be able to set the audio output device as the iphone? Or is this something that would require a companion app running on the phone to route the audio as well? Any information would be helpful, thanks!

What is the best way to go about sharing data between an app running on mac and iphone connected through USB. I know of a few products like https://www.duetdisplay.com/ that route your Mac's video output through USB to an app window running on iPad. I want to do the same but instead route my Mac's audio output to the iPhone speaker output in realtime. I have asked Swift developers and no luck yet. There is a library called https://libimobiledevice.org/ that communicates with mobile devices. Could this be a possible route? Or is this a job for an Objective C developer? Any info helps.