Android application for audio interception during calls

Demand: Intercept the audio during a call on an Android device Goal: Modify the audio signal that is transmitted and received during a Call Requirement 1: Audio Signal Interception – The audio should be intercepted and the original audio should NOT be transmitted; only the transformed signal should be transmitted. Requirement 2: The same should be done in the incoming audio of the call; The received signal should be intercepted and transformed and only the transformed audio should be transmitted to the audio output. To fulfill this project both requirements must be FULLY achieved.