Can a third-party app capture microphone audio while a cellular call is active?

We're building a companion app that people use during a regular cellular call (VoIP isn't an option for this call). The user wants to briefly mute the call, speak a short question into our app, then unmute.

  1. Is there any supported way for a third-party app to record from the microphone during an active cellular call, even if the call is muted or on hold?
  2. Does Siri with App Intents accept voice input during an active call? If so, is Siri's spoken response heard by the other person on the call?
  3. Can a watchOS app record audio while the paired iPhone is on a call?
  4. If none of these work, what approach do you recommend?

Thanks for your question on the posts.

There is no public API that allows a third-party app to capture microphone input (AVAudioEngine, AVAudioRecorder, SFSpeechRecognizer, or AudioUnit input) while a regular cellular call is active, that'll be againt the privacy policy in all cases including audio input route for privacy.

Apple Watch has its own physical microphone and its own local AVAudioSession managed by watchOS. If you want to record audio in watchOS I think you can do that. Look into AVAudioSession (.record or .playAndRecord)

Hope this helps, good luck on your project.

Albert  WWDR