Convert 3GPP file to MP3

Hi All, I am looking for a sample code that shows how to extract the audio stream from a 3GP file and convert to mp3. I would prefer if the code is in Java so we can integrate within our android app. But we are open for objective-C code. The 3GP file created in java using myRecorder = new MediaRecorder(); [login to view URL]([login to view URL]); [login to view URL](MediaRecorder.OutputFormat.THREE_GPP); [login to view URL](MediaRecorder.OutputFormat.AMR_NB); [login to view URL](path); We will provide a sample file. The output file should play ok on iOS and android (mp3)