Audio Tempo/Pitch Changing App

I need an app that will achieve the following: - import a song from the device's music library - change tempo by a percentage value (5% to 250%), 5% increments - change pitch by semitone (-12 to +12), 1 semitone increments - toggle looping, create loop time points (millisecond accuracy), save any number of loop sets (2 points per loop) that can be restored at a later time, only one loop set active at any time - toggle multitasking for devices that support it (continue playback when closing app) Priority must be placed on very high quality audio, even at the most extreme settings, with the lowest impact on device performance. Audio format up-conversion may be required upon song import to achieve this level of audio quality. Two versions of the app are required: - unrestricted paid version - free ad-enabled lite version The free version must have provision for in-app purchase to remove ads. Both versions should prompt the user to rate the app after using it for a period of time.