Force iPhone to output through the speaker, while recording from headphone mic

Question

As far as I've been able to tell, whenever you override an audio route in the iPhone, you have to change both the output AND input routes together. The only available routes I'm aware of are:

"Headset" "Headphone" "Speaker" "SpeakerAndMicrophone" "HeadphonesAndMicrophone" "HeadsetInOut" "ReceiverAndMicrophone" "Lineout"

Is there any way to record from the line input/headset in and play through the speaker?

Answer 1

After talking with Apple engineers on the Coreaudio mailing list, I've found it's not currently possible to do this with a single RemoteIO audio unit.

I'm going to try to instantiate two audio units, one for playing, the other for acquisition, but I'm not hopeful. We shall see.