iPhone (iOS4): is it possible to play music/sound during an active call?

I want to allow user to switch to my app during a phone call and play some sound that th开发者_开发知识库e second person will hear.

I see here that it was possible even before iOS4 and here that no one knows how to do it.

I will really appreciate if someone will spread some light on this issue.

Thank you.

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If you would like to play a song and after launch a phone call, any iPhone OS will stop your song, just beacause phone call has privilege over audio playback. What you can do is play a song after the call has started, but in this case you can only use speakers.

I've tried the second, and with great audio tracks and some simple advises, you can reach the desired effect.

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You could achieve it using Twilio API