title: Why it is not possible to play an audio file on a voice call in android
body: <p>This question might seem to be a repetition of the questions such as following: 
  <br/><a href="https://stackoverflow.com/questions/8784221/how-to-play-an-audio-file-on-a-voice-call-in-android">How to play an audio file on a voice call in android</a>
  <br/><a href="https://stackoverflow.com/questions/15588009/background-audio-for-a-call-in-progress-possible">Background Audio for a Call in Progress - Possible?</a></p>
  
  <p>The answers of these questions suggests that it is not possible to play a pre-recorded audio on a voice call in android. I want to know why it is not possible? What is the limitation (hardware/software)? Is it really a limitation or done purposely? Can we alter the source code of android to make it possible? </p>