On most iOS devices I’m testing on (e.g. iPhone S), if I request 2 input channels, I get 1…
On some later devices (e.g. iPhone X, iPad Air), if I request 2 input channels, I get 2…
If these 2 channels gave me different audio input (e.g. coming from different microphones, or somehow processed to make stereo effects), then I could understand and appreciate the feature. However, it looks as though both channels are giving me exactly identical live audio data.
This is a problem for me, because until I discovered this, I assumed that if I had access to 2 channels of audio, the audio must be coming from an external device with very different data on channels 0 and 1. Furthermore, even with an external device plugged in (via Camera Kit) that is not an iOS device, the audiodevicemanager’s current audio device is still an iOSAudioIODevice with the type name ‘iOS Audio’.
How can I differentiate between the two scenarios: 2 (identical) input channels from an iPhone X versus 2 input channels coming from an external device plugged in with a camera kit? I’m hoping the answer is not to do a sample-by-sample comparison of the data from each channel to see if they are equal or not.
What is the intended purpose of an iPhone giving me access to 2 identical channels of input audio?